Polymer matrix composite joint, system and method for treating polymer matrix composite joint

Abstract

The invention relates to a polymer matrix composite joint, a system and a method for treating a polymer matrix composite joint. A polymer matrix composite joint includes a first contact region of a first polymer matrix composite structure, a second contact region of a second polymer matrix composite structure, and a resistive film heating element. The resistive film heating element includes a lignin-based carbonaceous material. The resistive film heating element defines a longitudinal form and is disposed between the first contact area and the second contact area. The resistive film heating element is sized and shaped based on the first contact area and the second contact area. And the resistive film heating element is used for jointing the first polymer matrix composite structure and the second polymer matrix composite structure at the first contact area and the second contact area by adopting a resistance welding process. A system for treating a polymer matrix composite joint and a method for treating a polymer matrix composite joint are also disclosed.

Description

Technical Field

[0001] This disclosure generally relates to polymer matrix composite joints, and more specifically to systems and methods for processing polymer matrix composite joints. The processing of polymer matrix composite joints involves joining polymer matrix composite structures using a resistance film heating element and a resistance welding process. The resistance film heating element comprises a lignin-based carbon-containing material. In one example, the polymer matrix composite structure is a thermoplastic composite structure. In another example, the polymer matrix composite structure comprises a thermoset composite structure. Systems and methods for de-welding polymer matrix composite structures are also disclosed. Background Technology

[0002] Other emerging thermal bonding technologies, such as ultrasonic welding and induction welding, require positioning welding equipment or devices at a certain distance from the joint interface. This makes these methods difficult to implement in practice for welding thick composite components and / or geometrically complex components, such as closed-form composite box sections. Although existing welding technologies use thermoplastic heating elements dispersed with nanomaterials, providing further weight reduction at the weld joint and potentially reducing process time and energy, the repeatability of process efficiency and consistent weld quality can be problematic. This is because nanomaterials dispersed in the polymer matrix create random electropercolation networks, which are often difficult to control during the process, resulting in heating element elements with different electrical and thermal conductivity parameters. Resistance welding tests on multi-walled carbon nanotubes dispersed in thermoplastic heating element elements including polyethyleneimine revealed uneven heating in the weld area. Existing resistance heating technologies primarily use fossil-based nanomaterials, which are relatively expensive and limited in availability. Furthermore, existing technologies for welding thermoset composites propose solutions using ultrasonic welding or induction welding, or electromagnetic excitation based on electromagnetic induction, or microwave heating.

[0003] Therefore, those skilled in the art continue to devote research and development efforts to improve resistance welding and de-welding techniques for joining polymer-based composite structures, such as thermoplastic composite structures or thermosetting composite structures, using resistance film heating elements, including lignin-based carbonaceous materials. Summary of the Invention

[0004] Examples of polymer-based composite joints, systems, and methods for treating polymer-based composite joints are disclosed. The following is a non-exhaustive list of examples based on the subject matter of this disclosure, which may or may not be claimed.

[0005] In one example, the polymer-based composite joint includes a first contact region of a first polymer-based composite structure, a second contact region of a second polymer-based composite structure, and a resistance film heating element. The resistance film heating element comprises a lignin-based carbonaceous material. The resistance film heating element defines a longitudinal shape and is disposed between the first and second contact regions. The size and shape of the resistance film heating element are determined based on the first and second contact regions. The resistance film heating element is used to join the first and second polymer-based composite structures at the first and second contact regions using a resistance welding process.

[0006] In one example, a system for processing a polymer-based composite connector includes a polymer-based composite workpiece and a power source. The polymer-based composite workpiece includes the polymer-based composite connector. The power source has a power line connected to a first electrical connection on the polymer-based composite connector and a return line connected to a second electrical connection on the polymer-based composite connector.

[0007] In another example, a system for processing polymer-based composite joints includes a polymer-based composite workpiece. The polymer-based composite workpiece includes a polymer-based composite joint.

[0008] In one example, a method for processing a polymer-based composite joint includes: (1) identifying a first polymer-based composite structure and a second polymer-based composite structure to be joined by resistance welding; (2) placing a resistance film heating element on the first polymer-based composite structure over a first contact area of ​​the first polymer-based composite structure, the resistance film heating element comprising a lignin-based carbon-containing material and defining a longitudinal shape; and (3) placing the second polymer-based composite structure on the resistance film heating element such that a second contact area of ​​the second polymer-based composite structure is aligned with the first contact area of ​​the first polymer-based composite structure, the first contact area, the resistance film heating element, and the second contact area defining a stack for performing the resistance welding at the polymer-based composite joint.

[0009] In another example, a method for processing a polymer-based composite joint includes: (1) identifying a polymer-based composite joint to be resistively welded, the polymer-based composite joint including a first contact area of ​​a first polymer-based composite structure, a second contact area of ​​a second polymer-based composite structure, and a resistive film heating element comprising a lignin-based carbon-containing material, the resistive film heating element defining a longitudinal form and disposed between the first contact area and the second contact area; (2) connecting an electric line from a power source to a first electrical connection at a proximal end of the resistive film heating element; and (3) connecting a return line from the power source to a second electrical connection at a distal end of the resistive film heating element.

[0010] Other examples of the disclosed polymer-based composite joints, systems, and methods for treating polymer-based composite joints will become apparent from the following detailed description, accompanying drawings, and appended claims. Attached Figure Description

[0011] Figure 1 A top view and exploded side view of an example polymer-based composite joint are provided; Figure 2A This is an exploded side view of another example of a polymer-based composite joint; Figure 2B yes Figure 2A A top view of a polymer-based composite joint; Figure 3 This is a side view of an example of a resistance film heating element; Figure 4A This is a top view of an example of a first polymer-based composite material structure, showing the first contact area; Figure 4B This is a bottom view of an example of a second polymer-based composite structure, showing the second contact area; Figure 5A This is an exploded side view of yet another example of a polymer-based composite joint; Figure 5B yes Figure 5A A top view of a polymer-based composite joint; Figure 6 This is a functional block diagram of an example system for processing polymer-based composite joints; Figure 7 yes Figure 6 A functional diagram of an example system, in which tools are used to weld polymer-based composite joints in conjunction with the system. Figure 8This is a functional diagram of another example of a system for processing polymer-based composite material joints; Figure 9 yes Figure 7 A functional diagram of an example system, in which tools are combined to weld polymer-based composite joints; Figure 10 This is a flowchart illustrating an example of a method for treating polymer-based composite material joints; Figure 11 Combination Figure 10 This is a flowchart of another example of a method for treating polymer-based composite material joints; Figure 12 Combination Figure 10 and Figure 11 This is a flowchart of yet another example of a method for treating polymer-based composite material joints; Figure 13 Combination Figure 10 and Figure 11 This is yet another example of a flowchart for a method used to treat polymer-based composite material joints; Figure 14 Combination Figure 10 and Figure 11 This is yet another example of a flowchart for a method used to treat polymer-based composite material joints; Figure 15 Combination Figure 10 This is a flowchart of another example of a method for treating polymer-based composite material joints; Figure 16 Combination Figure 10 and Figure 15 This is a flowchart of yet another example of a method for treating polymer-based composite material joints; Figure 17 Combination Figure 10 , Figure 15 and Figure 16 This is yet another example of a flowchart for a method used to treat polymer-based composite material joints; Figure 18 Combination Figure 10 , Figure 15 and Figure 16 This is yet another example of a flowchart for a method used to treat polymer-based composite material joints; Figure 19 Combination Figure 10 , Figure 15 and Figure 16 This is a flowchart of another example of a method for treating polymer-based composite material joints; Figure 20 This is a flowchart illustrating another example of a method for treating polymer-based composite joints; Figure 21 Combination Figure 20 This is a flowchart of yet another example of a method for treating polymer-based composite material joints; Figure 22 Combination Figure 20 This is yet another example of a flowchart for a method used to treat polymer-based composite material joints; Figure 23 Combination Figure 20 and Figure 22 This is a flowchart of another example of a method for treating polymer-based composite material joints; Figure 24 Combination Figure 20 This is a flowchart of yet another example of a method for treating polymer-based composite material joints; Figure 25 Combination Figure 20 This is a flowchart of yet another example of a method for treating polymer-based composite material joints; Figure 26 Combination Figure 20 and Figure 25 This is yet another example of a flowchart for a method used to treat polymer-based composite material joints; Figure 27 This is a block diagram illustrating an aircraft production and service method for manufacturing polymer-based composite joints using one or more examples of the systems and methods disclosed herein for processing polymer-based composite joints; and Figure 28 This is a schematic diagram of an aircraft that incorporates one or more examples of the systems and methods disclosed herein for processing polymer-based composite joints. Detailed Implementation

[0012] Various examples of the polymer-based composite joint 200, systems 600 and 800 for processing the polymer-based composite joint 200, and methods 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, and 2600 disclosed herein provide techniques for welding and de-welding a first contact region 202 of a first polymer-based composite structure 204 to a second contact region of a second polymer-based composite structure 208 using a resistance film heating element 210. The resistance film heating element 210 comprises a lignin-based carbon-containing material 212. In one example, the first and second polymer-based composite structures 204 and 208 comprise thermoplastic composite structures 226 and 228. In another example, the first polymer-based composite structure 204 and the second polymer-based composite structure 208 include thermosetting composite structures 502 and 505.

[0013] The reversible assembly / disassembly methods for thermosetting and thermoplastic composites disclosed herein utilize lignin-based graphite or graphene films as heating elements for resistance welding and desoldering processes. These methods aim to improve upon certain existing features and / or reduce some of the drawbacks of previous methods. For example, the methods disclosed herein can provide superior weld quality through relatively more uniform heat dissipation, while reducing the operating costs and power input of welding and desoldering processes. Due to their superior electrical and thermal conductivity compared to conventional resistance welding heating elements such as metal mesh, carbon fiber fabric, or fossil-based nanomaterials, lignin-based graphite or graphene films offer higher energy efficiency and in-plane heat dissipation.

[0014] Compared to existing nanomaterial-based heating element solutions (such as conventional graphene and carbon nanotubes), this method, using, for example, lignin-based graphene or graphite resistance heating elements, offers a greater cost reduction in the initial investment in welding. For instance, lignin may be less expensive and readily available in large quantities from the paper industry. The reversible method disclosed herein enables the disassembly of end-of-life composite structures, reducing logistics and recycling costs, particularly for large welded structures that are typically difficult to transport or handle for recycling. Furthermore, the method causes minimal damage to the disassembled end-of-life composite structure, which can then be further used in recycling processes to obtain intact reinforcing fibers.

[0015] This method provides reversible assembly / disassembly for both thermoplastic and thermoset composites, expanding the applicability of resistance welding and de-welding techniques. For reversible assembly / disassembly of thermoset composite joints, a lignin-based film heater is sandwiched between thermoplastic films and integrated with the thermoset joint, allowing for welding and de-welding of the thermoset composite based on separating the joint at the thermoplastic film. The assembly / disassembly method disclosed herein facilitates the recycling process of composites and reduces the carbon footprint of each indirectly related industrial step by leveraging further sustainable solutions. Furthermore, the use of bio-derived materials as heating element elements for welding can also have a positive impact on the carbon footprint of product development. This could be a contributing factor to the aerospace industry's goal of achieving net-zero carbon emissions by 2050.

[0016] The technical objectives and characteristics of assembly and disassembly processes fall into two categories: (1) assembling, for example, thermosetting or thermoplastic composite materials via resistance welding, and (2) disassembling, for example, thermosetting or thermoplastic composite materials via resistance welding.

[0017] Case 1 – Assembling thermosetting or thermoplastic composite materials via resistance welding.

[0018] Resistance welding is a type of thermal bonding method that, due to its molecular structure, provides a physical fusion bond between thermoplastic parts. At the joint interface of two thermoplastic parts, heat is generated using a so-called heating element or resistance heater, where a power source is connected to the heating element via electrodes so that heat is generated when current flows through the conductive network of the heating element. In the welding process, uniform pressure is typically applied simultaneously to ensure bonding between the surfaces at the welding interface by achieving close contact and promoting self-adhesion or molecular diffusion of polymer chains between the parts to be joined.

[0019] refer to Figure 1 An example of an assembly method for the ω-shaped fuselage stiffener 100 and fuselage skin 101 is described using resistance welding. Figure 1 The upper part provides a top view of the connector. Figure 1The lower part provides an exploded side view of the joint. The assembly method incorporates the ω-shaped stiffener 100 and the fuselage skin 101, both made of fiber-reinforced polymer composites (e.g., unidirectional carbon fiber reinforced composites). Two lignin-based graphite or graphene resistance film heaters 102 are positioned between the fuselage skin 101 and the flange of the ω-shaped stiffener 100. The resistance film heaters 102 may be made of a blend of thermoplastic polymers and lignin-based graphite or graphene sheets (e.g., a blend of lignin-based graphene and polyvinyl alcohol) to increase the flexibility of the film heaters, thereby adapting them to any geometry according to the shape and size requirements of the joint interface. The type of polymer blend and the weight ratio of polymer to graphene or graphite sheets in the resistance film heaters 102 may vary depending on the process temperature required for welding. A lignin-based graphite or graphene resistance film heater 102 can also be sandwiched between thermoplastic films 103 (e.g., with a thickness between 20 and 100 μm) for resistance welding of thermoplastic and / or thermosetting composites. Adding an additional thermoplastic layer at the interface may increase the joint thickness. Adding a thermoplastic film (up to 100 μm) at the joint interface can help improve the interlaminar mechanical properties of the joint by introducing a resin-rich layer at the interface. In the case of assembling carbon fiber reinforced composites, an additional resin-rich layer can help avoid a common problem in resistance welding, namely so-called current leakage—which may occur due to excessive lateral extrusion of the molten thermoplastic flow under pressure, causing the conductive carbon fibers to come into direct contact with the graphene. Therefore, this method adds an additional thermoplastic film 103 to sandwich the heating element 102, although the additional thermoplastic film 103 may be omitted for successful resistance welding of thermoplastic composites. For assembling thermosetting composites via resistance welding, the heating element 102 needs to be sandwiched between thermoplastic films 103 to ensure optimal bonding at the joint. Prior to the resistance welding process, the heating element 102 may be sandwiched between thermoplastic films 103 and solidified in a separate step (e.g., via pressure solidification). This allows the heating element to be shaped to the desired geometry associated with the geometric complexity of the joint interface, reducing entrained volatile gases and moisture in the resin-rich polymer, and controlling the thickness of the sandwiched heating element 102, which is subsequently used in the assembly step via resistance welding.

[0020] On the other hand, it is to ensure uniform in-plane heating in the welding area without causing polymer degradation in the polymer matrix of the components 100, 101 to be welded, in the graphene or graphite-based heating element 102 (in the case of blending with thermoplastics), and in the thermoplastic film 103. Degradation and / or chemical decomposition in the polymer matrix of any component at the joint can reduce the joint strength. Therefore, the thermoplastic film 103 and the thermoplastic polymer that can be blended into the resistance film heater 102 can be selected for the melt temperature of the composite components 100, 101 to be welded. More specifically, the melt temperature of the added thermoplastic can be equal to or lower than the melt and / or processing temperature of the composite components 100, 101 to be welded. For example, for welding thermosetting composites, the thermoplastic film 103 can be made of linear low-density polyethylene, polypropylene, or polyvinyl alcohol, whose melt temperature is generally equal to or lower than the processing temperature of advanced thermosetting composites (e.g., generally lower than 200°C).

[0021] like Figure 1 As shown in the side view, the length of the heating element 102 may be slightly shorter than that of the thermoplastic film 103 (e.g., a few millimeters) to prevent any direct contact between the heating element and the composite material parts 100, 101, thereby avoiding any potential current leakage in the case that at least one of the composite material parts 100, 101 contains conductive fibers (e.g., carbon fibers). Figure 1 The top view shows an example where the length of the heating element 102 is slightly longer than the length of the stiffener 100 (represented as "L" in the figure) (e.g., a few millimeters) to ensure the accessibility of the conductive electrode 104. The conductive electrode 104 may be made of copper (e.g., copper mesh). A DC power supply can be connected to the heating element 102 using a cable or wire 105 and the conductive electrodes 104 attached to both ends of each resistive film heating element 104. In the event of high electrical contact resistance between the electrode 104 and the heating element 102, a conductive adhesive (e.g., conductive silver adhesive) may be applied between the heating element 102 and the electrode 104. The maximum operating temperature of the conductive adhesive is compatible with the expected operating temperature of the heating element 102.

[0022] In a resistance heating welding process, heating element 102 can heat the joint interface to a desired temperature, thereby allowing the joint surfaces to begin close contact and the diffusion of thermoplastic molecules. A uniform and constant pressure (denoted as "P (bar)") can also be applied simultaneously to the flange region of the ω-shaped stiffener. The pressure can be applied using automated equipment (e.g., a robot head) or rigid tools (e.g., metal tools).

[0023] Scenario 2 – Disassembly of thermosetting or thermoplastic composite materials via resistance welding.

[0024] The technical objectives and concerns of disassembly methods for thermoset and / or thermoplastic composites can differ from those of assembly methods. One of the main concerns of the disassembly methods presented here is to separate welded, end-of-service structures without damaging welded components. This can ultimately enable the recovery of a larger quantity of intact fibers through recycling processes. Furthermore, this can also lead to better valuation of components that can be recycled and / or directly used in other industries.

[0025] In Case 2, the disassembly method is described as disassembling the welded components assembled in the assembly method of Case 1. Since the same configuration as in Case 1 is assumed, only the exploded side view of the welded composite material components, namely the ω-shaped fuselage stiffener 100 and the fuselage skin 101, needs to be referenced. Similar to the assembly method shown in Case 1, the heating element 102 softens the weld interface through resistance heating. A thin thermocouple can be used to monitor the weld surface temperature to minimize interference with temperature uniformity at the weld surface. Once the desired temperature is reached at the weld surface, [the process is as follows]. Figure 1 The tensile force (“N (kN)”) shown can be applied across the entire cross-section of stiffener 100. The tensile force (“N (kN)”) is... Figure 1 The “P (bar)” force is shown as the reverse force. The fuselage skin 101 can be positioned (e.g., using a clamp or tool) to facilitate the disassembly process. Successful disassembly relies on precise temperature measurements at the weld interface, as this can be a key guiding parameter for separating the surfaces with minimal pulling force.

[0026] Overall reference Figures 2A-2B , Figure 3 , Figures 4A-4B , Figures 5A-5B and Figure 6 As an example, this disclosure relates to a polymer-based composite joint 200. Figure 2A This is an exploded side view of an example of a polymer-based composite joint 200. Figure 2B yes Figure 2A Top view of polymer-based composite joint 200. Figure 3 This is a side view of an example of a resistance film heating element 210. Figure 4A This is a top view of an example of a first polymer-based composite structure 204, showing the first contact region 202. Figure 4B This is a bottom view of an example of the second polymer-based composite structure 208, showing the second contact area 206. Figure 5A This is an exploded side view of yet another example of a polymer-based composite joint 200. Figure 5B yes Figure 5A Top view of polymer-based composite joint 200. Figure 6 This is a functional block diagram of an example of a system 600 for processing polymer-based composite material joints 200.

[0027] See again Figures 2A-2B , Figure 3 , Figures 4A-4B , Figures 5A-5B and Figure 6 In one or more examples, the polymer-based composite joint 200 includes a first contact region 202 of a first polymer-based composite structure 204, a second contact region 206 of a second polymer-based composite structure 208, and a resistance film heating element 210. The size and shape of the second contact region 206 are defined based on the first contact region 202. The resistance film heating element 210 includes a lignin-based carbonaceous material 212. The resistance film heating element 210 defines a longitudinal form and is disposed between the first contact region 202 and the second contact region 206. The size and shape of the resistance film heating element 210 are defined based on the first contact region 202 and the second contact region 206. The resistance film heating element 210 is used to join the first polymer-based composite structure 204 and the second polymer-based composite structure 208 at the first contact region 202 and the second contact region 206 using a resistance welding process.

[0028] In another example of the polymer-based composite connector 200, the first polymer-based composite structure 204 and the second polymer-based composite structure 208 comprise thermoplastic materials. In yet another example of the polymer-based composite connector 200, the lignin-based carbon-containing material 212 comprises any suitable combination of lignin-based graphene material, lignin-based graphite material, lignin-based graphene sheets, lignin-based graphite sheets, or any other suitable lignin-based carbon-containing material. In yet another example of the polymer-based composite connector 200, the resistance film heating element 210 further comprises a thickness of approximately 1 nm to approximately 10 nm, approximately 10 nm to approximately 100 nm, approximately 100 nm to approximately 1 μm, approximately 1 μm to approximately 10 μm, approximately 10 μm to approximately 100 μm, approximately 100 μm to approximately 1 mm, or any other suitable thickness. In yet another example of the polymer-based composite connector 200, the length of the resistance film heating element 210 comprises the maximum length determined by the conductivity of the resistance film heating element 210 and the desired current flowing through it. In a further example, where the lengths of the first polymer-based composite structure 204 and the second polymer-based composite structure 208 exceed the maximum length of the resistance film heating element 210, an additional resistance film heating element 210 is used to form an additional polymer-based composite joint 200 to fully bond the first polymer-based composite structure 204 and the second polymer-based composite structure 208.

[0029] In another example of the polymer-based composite joint 200, the resistance film heating element 210 further includes a composite material 302 having a polymer matrix 304. A lignin-based carbonaceous material 212 is blended with the polymer matrix 304. In a further example, the polymer matrix 304 comprises any suitable combination of polypropylene, polybutadiene, polyvinyl alcohol, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, or any other suitable polymer material. In yet another further example, the composite material 302 of the resistance film heating element 210 has a thickness of approximately 1 nm to approximately 10 nm, approximately 10 nm to approximately 100 nm, approximately 100 nm to approximately 1 μm, approximately 1 μm to approximately 10 μm, approximately 10 μm to approximately 100 μm, approximately 100 μm to approximately 1 mm, or any other suitable thickness. In yet another example of the polymer-based composite joint 200, the first contact region 202, the resistance film heating element 210, and the second contact region 206 are in close and continuous contact. In another example of the polymer-based composite joint 200, a resistance welding process is used to self-adhere the first contact area 202, the resistance film heating element 210, and the second contact area 206.

[0030] In yet another example of the polymer-based composite joint 200, incorporating a resistance welding process, the first contact region 202, the resistance film heating element 210, and the second contact region 206 are joined by entanglement between the polymer chains of the first contact region 202 and the second contact region 206. In another example of the polymer-based composite joint 200, incorporating a resistance welding process, the first contact region 202, the resistance film heating element 210, and the second contact region 206 are joined by molecular diffusion of the polymer chains of the first contact region 202 and the second contact region 206. In yet another example, the polymer-based composite joint 200 also includes at least one temperature sensor 214 embedded in the polymer-based composite joint 200 near the resistance film heating element 210, with one or more leads 216 of each temperature sensor 214 exposed externally for connection to a temperature controller 610. In a further example, at least one temperature sensor 214 includes any suitable combination of one or more thermocouples, one or more resistance temperature detectors, one or more thermistors, or any other suitable temperature sensor.

[0031] In another example of the polymer-based composite joint 200, a first polymer-based composite structure 204 includes a first thermosetting composite structure 502 having a first contact region 202, while a second polymer-based composite structure 208 includes a second thermosetting composite structure 504 having a second contact region 206. In this example, the polymer-based composite joint 200 also includes a first thermoplastic film 506 and a second thermoplastic film 508. The first thermoplastic film 506 is disposed between the first contact region 202 of the first thermosetting composite structure 502 and the resistance film heating element 210. The size and shape of the first thermoplastic film 506 are determined based on the first contact region 202 and the resistance film heating element 210. The second thermoplastic film 508 is disposed between the resistance film heating element 210 and the second contact region 206 of the second thermosetting composite structure 504. The size and shape of the second thermoplastic film 508 are determined based on the resistance film heating element 210 and the second contact region 206.

[0032] In a further example, the first thermoplastic film 506 and the second thermoplastic film 508 have a thickness of approximately 20 μm to approximately 100 μm. In another further example, the first thermoplastic film 506 and the second thermoplastic film 508 comprise any suitable combination of linear low-density polyethylene, polypropylene, polyvinyl alcohol, or any other suitable polymer material. In yet another further example, the resistance film heating element 210, the first thermoplastic film 506, and the second thermoplastic film 508 are used to join the first thermosetting composite structure 502 and the second thermosetting composite structure 504 at the first contact area 202 and the second contact area 206 using a resistance welding process. In yet another further example, the first contact area 202, the first thermoplastic film 506, the resistance film heating element 210, the second thermoplastic film 508, and the second contact area 206 are in close and continuous contact.

[0033] In yet another further example, incorporating resistance welding, the first contact region 202, the first thermoplastic film 506, the resistance film heating element 210, the second thermoplastic film 508, and the second contact region 206 are joined by self-adhesive bonding. In yet another further example, incorporating resistance welding, the first contact region 202, the first thermoplastic film 506, the resistance film heating element 210, the second thermoplastic film 508, and the second contact region 206 are joined by entanglement between the polymer chains of the first contact region 202 and the first thermoplastic film 506, and by entanglement between the polymer chains of the second thermoplastic film 508 and the second contact region 206. In yet another further example, incorporating resistance welding, the first contact region 202, the first thermoplastic film 506, the resistance film heating element 210, the second thermoplastic film 508, and the second contact region 206 are joined by molecular diffusion of the polymer chains of the first contact region 202, the first thermoplastic film 506, the second thermoplastic film 508, and the second contact region 206.

[0034] In another example of the polymer-based composite connector 200, the longitudinal configuration of the resistance film heating element 210 defines a proximal end 218 and a distal end 220. In this example, the polymer-based composite connector 200 also includes a first electrical connection 222 and a second electrical connection 224. The first electrical connection 222, located at the proximal end 218 of the resistance film heating element 210, is for receiving a power line 606 from a power source 604. The second electrical connection 224, located at the distal end 220 of the resistance film heating element 210, is for receiving a return line 608 from a power source 604. In a further example, the first electrical connection 222 and the second electrical connection 224 comprise any suitable combination of copper, copper alloy, copper mesh, aluminum, aluminum alloy, or any other suitable conductive material. In yet another further example, the power source 604 comprises a DC power source.

[0035] Overall reference Figures 2A-2B , Figures 5A-5B , Figure 6 and Figure 7 As an example, this disclosure relates to a system 600 for processing a polymer-based composite joint 200. Figure 2A This is an exploded side view of an example of a polymer-based composite joint 200. Figure 2B yes Figure 2A Top view of polymer-based composite joint 200. Figure 5A This is an exploded side view of yet another example of a polymer-based composite joint 200. Figure 5B yes Figure 5A Top view of polymer-based composite joint 200. Figure 6 This is a functional block diagram of an example of a system 600 for processing polymer-based composite material joints 200. Figure 7 yes Figure 6 A functional diagram of an example of system 600, in which tool 702 is used in conjunction with de-welding of polymer-based composite joint 200.

[0036] See again Figures 2A-2B , Figures 5A-5B , Figure 6 and Figure 7 In one or more examples, a system 600 for processing a polymer-based composite connector 200 includes a polymer-based composite workpiece 602 and a power supply 604. The polymer-based composite workpiece 602 includes the polymer-based composite connector 200. The power supply 604 includes a power line 606 connected to a first electrical connection 222 and a return line 608 connected to a second electrical connection 224.

[0037] In another example of system 600, the polymer-based composite connector 200 also includes at least one temperature sensor 214 embedded in the polymer-based composite connector 200 near the resistance film heating element 210, with one or more leads 216 of each temperature sensor 214 exposed externally. In this example, system 600 also includes a temperature controller 610, wherein one or more control lines 612 are connected to one or more leads 216 of at least one temperature sensor 214 to determine the current temperature of the resistance film heating element 210, while at least one additional line 614 is connected to a power supply 604 to control the current flowing through the resistance film heating element 210 in response to the current temperature. In a further example, after a third predetermined temperature of the resistance film heating element 210 is reached, the first contact area 202 of the first polymer-based composite structure 204 is de-welded from the second contact area 206 of the second polymer-based composite structure 208. In another further example, system 600 also includes at least one tool 702 to selectively separate the first contact area 202 from the second contact area 206 after the first contact area 202 of the first polymer matrix composite structure 204 and the second contact area 206 of the second polymer matrix composite structure 208 have been de-welded. In an even further example, at least one tool 702 includes any suitable combination of one or more robotic end effectors, one or more hoists, one or more cranes, or any other suitable tools.

[0038] In another example of system 600, a first polymer-based composite structure 204 includes a first thermosetting composite structure 502 having a first contact region 202, while a second polymer-based composite structure 208 includes a second thermosetting composite structure 504 having a second contact region 206. In this example, the polymer-based composite joint 200 also includes a first thermoplastic film 506 and a second thermoplastic film 508. The first thermoplastic film 506 is disposed between the first contact region 202 of the first thermosetting composite structure 502 and the resistance film heating element 210. The size and shape of the first thermoplastic film 506 are determined based on the first contact region 202 and the resistance film heating element 210. The second thermoplastic film 508 is disposed between the resistance film heating element 210 and the second contact region 206 of the second thermosetting composite structure 504. The size and shape of the second thermoplastic film 508 are determined based on the resistance film heating element 210 and the second contact region 206.

[0039] In a further example, the polymer-based composite joint 200 also includes at least one temperature sensor 214 embedded in the polymer-based composite joint 200 near the resistance film heating element 210, with one or more leads 216 of each temperature sensor 214 exposed externally. In this example, the system 600 also includes a temperature controller 610, wherein one or more control lines 612 are connected to one or more leads 216 of at least one temperature sensor 214 to determine the current temperature of the resistance film heating element 210, while at least one additional line 614 is connected to a power supply 604 to control the current flowing through the resistance film heating element 210 in response to the current temperature. In an even further example, after a third predetermined temperature of the resistance film heating element 210 is reached, the first contact area 202 of the first thermosetting composite structure 502 is de-welded from the second contact area 206 of the second thermosetting composite structure 504. In another further example, system 600 also includes at least one tool 702 to selectively separate the first contact area 202 from the second contact area 206 after the first contact area 202 of the first thermoset composite structure 502 and the second contact area 206 of the second thermoset composite structure 504 have been de-welded.

[0040] Overall reference Figures 2A-2B , Figures 5A-5B and Figures 6-9 As an example, this disclosure relates to a system 800 for processing polymer-based composite material joints 200. Figure 2A This is an exploded side view of an example of a polymer-based composite joint 200. Figure 2B yes Figure 2A A top view of a polymer-based composite joint 200. Figure 5AThis is an exploded side view of yet another example of a polymer-based composite joint 200. Figure 5B yes Figure 5A A top view of a polymer-based composite joint 200. Figure 6 This is a functional block diagram of an example of a system 600 for processing polymer-based composite material joints 200. Figure 7 yes Figure 6 A functional diagram of an example of system 600, in which tool 702 is used in conjunction with de-welding of polymer-based composite joint 200. Figure 8 This is a functional diagram of an example of a system 800 for processing polymer-based composite material joints 200. Figure 9 yes Figure 7 A functional diagram of an example of system 800, in which tool 902 is used in conjunction with welding of polymer-based composite joint 200.

[0041] See again Figures 2A-2B , Figures 5A-5B and Figures 6-9 In one or more examples, a system 800 for processing a polymer-based composite joint 200 includes a polymer-based composite workpiece 802. The polymer-based composite workpiece 802 includes the polymer-based composite joint 200. In another example, the system 800 further includes at least one tool 902 to selectively apply pressure to the polymer-based composite joint 200, thereby holding a stack of a first contact area 202 of a first polymer-based composite structure 204, a resistance film heating element 210, and a second contact area 206 of a second polymer-based composite structure 208 in place for a resistance welding process. In a further example, at least one tool 902 includes any suitable combination of one or more clamps, one or more locking clamps, one or more robotic end effectors, or other suitable tools.

[0042] In another example of system 800, the longitudinal configuration of the resistance film heating element 210 defines a proximal end 218 and a distal end 220. In this example, the polymer-based composite connector 200 further includes a first electrical connection 222 and a second electrical connection 224. The first electrical connection 222 is located at the proximal end 218 of the resistance film heating element 210. The second electrical connection 224 is located at the distal end 220 of the resistance film heating element 210. In this example, system 800 also includes a power supply 604, wherein a power line 606 is connected to the first electrical connection 222, and a return line 608 is connected to the second electrical connection 224. In a further example, the polymer-based composite connector 200 also includes at least one temperature sensor 214 embedded in the polymer-based composite connector 200 near the resistance film heating element 210, with one or more leads 216 of each temperature sensor 214 exposed externally. In this example, system 800 also includes a temperature controller 610, wherein one or more control lines 612 are connected to one or more leads 216 of at least one temperature sensor 214 to determine the current temperature of the resistive film heating element 210, and at least one additional line 614 is connected to a power supply 604 to control the current flowing through the resistive film heating element 210 in response to the current temperature.

[0043] In a further example, system 800 also includes at least one tool 902 to selectively apply a consolidation force to the polymer matrix composite joint 200 after a first predetermined temperature of the resistive film heating element 210 is reached, thereby consolidating the stack of the first contact area 202 of the first polymer matrix composite structure 204, the second contact area 206 of the resistive film heating element 210 and the second polymer matrix composite structure 208. In yet another further example, at least one tool 902 includes any suitable combination of one or more clamps, one or more locking clamps, one or more robotic end effectors, or any other suitable tools. In yet another further example, after the second predetermined temperature of the resistive film heating element 210 is reached, the first contact area 202 is welded to the second contact area 206 using the resistive film heating element 210 between the first contact area 202 of the first polymer matrix composite structure 204 and the second contact area 206 of the second polymer matrix composite structure 208.

[0044] In another example of system 800, a first polymer-based composite structure 204 includes a first thermosetting composite structure 502 having a first contact region 202, while a second polymer-based composite structure 208 includes a second thermosetting composite structure 504 having a second contact region 206. In this example, the polymer-based composite joint 200 also includes a first thermoplastic film 506 and a second thermoplastic film 508. The first thermoplastic film 506 is disposed between the first contact region 202 of the first thermosetting composite structure 502 and the resistance film heating element 210. The size and shape of the first thermoplastic film 506 are determined based on the first contact region 202 and the resistance film heating element 210. The second thermoplastic film 508 is disposed between the resistance film heating element 210 and the second contact region 206 of the second thermosetting composite structure 504. The size and shape of the second thermoplastic film 508 are determined based on the resistance film heating element 210 and the second contact region 206. In a further example, system 800 also includes at least one tool 902 to selectively apply pressure to polymer-based composite joint 200 to hold in place a stack of a first contact area 202 of a first thermosetting composite structure 502, a first thermoplastic film 506, a resistance film heating element 210, a second thermoplastic film 508, and a second contact area 206 of a second thermosetting composite structure 504 for a resistance welding process.

[0045] In another further example, the longitudinal configuration of the resistance film heating element 210 defines a proximal end 218 and a distal end 220. In this example, the polymer-based composite connector 200 also includes a first electrical connection 222 and a second electrical connection 224. The first electrical connection 222 is located at the proximal end 218 of the resistance film heating element 210. The second electrical connection 224 is located at the distal end 220 of the resistance film heating element 210. In this example, the system 800 also includes a power supply 604, wherein a power line 606 is connected to the first electrical connection 222, and a return line 608 is connected to the second electrical connection 224. In an even further example, the polymer-based composite connector 200 also includes at least one temperature sensor 214 embedded in the polymer-based composite connector 200 near the resistance film heating element 210, with one or more leads 216 of each temperature sensor 214 exposed externally. In this example, system 800 also includes a temperature controller 610, wherein one or more control lines 612 are connected to one or more leads 216 of at least one temperature sensor 214 to determine the current temperature of the resistive film heating element 210, and at least one additional line 614 is connected to a power supply 604 to control the current flowing through the resistive film heating element 210 in response to the current temperature.

[0046] In a further example, system 800 also includes at least one tool 902 to selectively apply a consolidation force to polymer-based composite joint 200 after a first predetermined temperature of the resistance film heating element 210 is reached, thereby consolidating a stack of a first contact area 202 of a first thermosetting composite structure 502, a first thermoplastic film 506, the resistance film heating element 210, a second thermoplastic film 508, and a second contact area 206 of a second thermosetting composite structure 504. In yet another further example, after a second predetermined temperature of the resistance film heating element 210 is reached, the first contact area 202 is welded to the second contact area 206 using the first thermoplastic film 506, the resistance film heating element 210, and the second thermoplastic film 508 between the first contact area 202 of the first thermosetting composite structure 502 and the second contact area 206 of the second thermosetting composite structure 504.

[0047] Overall reference Figures 2A-2B , Figure 3 , Figures 5A-5B , Figure 6 , Figure 9 and Figures 10-19 As an example, this disclosure relates to methods 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, and 1900 for treating polymer-based composite joints 200. Figure 2A This is an exploded side view of an example of a polymer-based composite joint 200. Figure 2B yes Figure 2A Top view of polymer-based composite joint 200. Figure 3 This is a side view of an example of a resistance film heating element 210. Figure 5A This is an exploded side view of yet another example of a polymer-based composite joint 200. Figure 5B yes Figure 5A Top view of polymer-based composite joint 200. Figure 6 This is a functional block diagram of an example of a system 600 for processing polymer-based composite material joints 200. Figure 9 yes Figure 7 A functional diagram of an example of system 800, in which tool 902 is used in conjunction with welding of polymer-based composite joint 200. Figure 10 An example of a method 1000 for treating a polymer-based composite joint 200 is provided. Figure 11 Combination Figure 10 An example of a method 1100 for treating a polymer-based composite joint 200 is provided.

[0048] Figure 12 Combination Figure 10 and Figure 11An example of a method 1200 for treating a polymer-based composite joint 200 is provided. Figure 13 Combination Figure 10 and Figure 11 An example of a method 1300 for treating a polymer-based composite joint 200 is provided. Figure 14 Combination Figure 10 and Figure 11 An example of a method 1400 for treating a polymer-based composite joint 200 is provided. Figure 15 Combination Figure 10 An example of a method 1500 for treating a polymer-based composite joint 200 is provided. Figure 16 Combination Figure 10 and Figure 15 An example of a method 1600 for treating a polymer-based composite joint 200 is provided. Figure 17 Combination Figure 10 , Figure 15 and Figure 16 An example of a method 1700 for treating a polymer-based composite joint 200 is provided. Figure 18 Combination Figure 10 , Figure 15 and Figure 16 An example of a method 1800 for treating a polymer-based composite joint 200 is provided. Figure 19 Combination Figure 10 , Figure 15 and Figure 16 An example of a method 1900 for treating a polymer-based composite joint 200 is provided.

[0049] See again Figures 2A-2B and Figure 10 In one or more examples, method 1000 for treating polymer-based composite joint 200 (see...) Figure 10 The process includes identifying a first polymer-based composite structure 204 and a second polymer-based composite structure 208 to be resistance welded together at 1002. At 1004, a resistance film heating element 210 is placed on the first polymer-based composite structure 204 above a first contact region 202 of the first polymer-based composite structure 204. The resistance film heating element 210 comprises a lignin-based carbonaceous material 212 and defines a longitudinal shape. At 1006, the second polymer-based composite structure 208 is placed on the resistance film heating element 210 such that a second contact region 206 of the second polymer-based composite structure 208 is aligned with the first contact region 202 of the first polymer-based composite structure 204. The first contact region 202, the resistance film heating element 210, and the second contact region 206 define a stack for resistance welding at the polymer-based composite joint 200.

[0050] In another example of method 1000, the first polymer-based composite structure 204 and the second polymer-based composite structure 208 comprise thermoplastic materials. In yet another example of method 1000, the lignin-based carbon-containing material 212 comprises any suitable combination of lignin-based graphene material, lignin-based graphite material, lignin-based graphene sheets, lignin-based graphite sheets, or any other suitable lignin-based carbon-containing material. In yet another example of method 1000, the resistance film heating element 210 further comprises a composite material 302 having a polymer matrix 304. In this example, the lignin-based carbon-containing material 212 is blended with the polymer matrix 304. In yet another example, method 1000 further comprises selectively applying pressure 1008 to the polymer-based composite joint 200 using at least one tool 902 to hold the stack of the first contact area 202 of the first polymer-based composite structure 204, the resistance film heating element 210, and the second contact area 206 of the second polymer-based composite structure 208 in place for resistance welding. In a further example, the first contact area 202, the resistive film heating element 210, and the second contact area 206 are in close and continuous contact.

[0051] See again Figures 2A-2B , Figure 6 , Figure 10 and Figure 11 In one or more examples, method 1100 for treating polymer-based composite joint 200 (see...) Figure 11 )include Figure 10 Method 1000 continues from 1006 to 1102. In this example, the first polymer-based composite structure 204 includes a first thermoplastic composite structure 226 having a first contact region 202, while the second polymer-based composite structure 208 includes a second thermoplastic composite structure 228 having a second contact region 206. At 1102, an electric line 606 is connected from a power source 604 to a first electrical connection 222 at the proximal end 218 of the resistance film heating element 210. At 1104, a return line 608 is connected from the power source 604 to a second electrical connection 224 at the distal end 220 of the resistance film heating element 210. At 1106, the power source 604 is activated to provide electrical energy to the resistance film heating element 210, thereby allowing current to flow through the resistance film heating element 210. At 1108, in response to the current, heat is generated at the resistive film heating element 210, and thermal radiation is distributed through the polymer-based composite joint 200 to weld the first contact area 202 of the first thermoplastic composite structure 226 to the second contact area 206 of the second thermoplastic composite structure 228.

[0052] See again Figures 2A-2B , Figure 6 and Figures 9-12 In one or more examples, method 1200 for treating polymer-based composite joint 200 (see...) Figure 12 )include Figure 10 Method 1000 and Figure 11 Method 1100, and continuing from 1108 to 1202, at 1202, after reaching a first predetermined temperature of the resistance film heating element 210, selectively applies a consolidation force to the polymer-based composite joint 200 using at least one tool 902 to consolidate the stack of the first contact area 202 of the first thermoplastic composite structure 226, the resistance film heating element 210, and the second contact area 206 of the second thermoplastic composite structure 228. In another example, method 1200 again continues from 1108 to 1204, at 1204, after reaching a second predetermined temperature of the resistance film heating element 210, welding the first contact area 202 to the second contact area 206 using the resistance film heating element 210 between the first contact area 202 of the first thermoplastic composite structure 226 and the second contact area 206 of the second thermoplastic composite structure 228. In a further example, the method continues from 1204 to 1206, where heat is generated at the resistance film heating element 210 to spread thermal radiation through the polymer-based composite joint 200 to de-weld the polymer-based composite joint 200, thereby separating the first contact area 202 of the first thermoplastic composite structure 226 from the second contact area 206 of the second thermoplastic composite structure 228.

[0053] See again Figures 2A-2B , Figure 6 , Figure 10 , Figure 11 and Figure 13 In one or more examples, method 1300 for treating polymer-based composite joint 200 (see...) Figure 13 )include Figure 10 Method 1000 and Figure 11Method 1100, and continuing from 1106 to 1302, at 1302, at least one temperature sensor 214 is placed near the resistive film heating element 210, with one or more leads 216 of each temperature sensor 214 exposed externally. At 1304, one or more control lines 612 are connected from the temperature controller 610 to one or more leads 216 of each temperature sensor 214. At 1306, at least one additional line 614 is connected from the temperature controller 610 to the power supply 604. At 1308, the temperature controller 610 is enabled in conjunction with the activation of the power supply 604. At 1310, the current temperature of the resistive film heating element 210 is determined at the temperature controller 610 based at least in part on one or more signals from at least one temperature sensor 214. At 1312, the current temperature of the resistive film heating element 210 is compared with a predetermined temperature profile of the resistive film heating element 210. At 1314, the current flowing from power supply 604 through resistive film heating element 210 is controlled based on this comparison. Method 1300 continues from 1314, to... Figure 11 1108.

[0054] See again Figures 2A-2B , Figure 9 , Figure 10 , Figure 11 and Figure 14 In one or more examples, method 1400 for treating polymer-based composite joint 200 (see...) Figure 14 )include Figure 10 Method 1000 and Figure 11 Method 1100, and continuing from 1108 to 1402, at 1402, after the current temperature of the resistance film heating element 210 reaches the desired temperature, selectively applies a consolidation force to the polymer-based composite joint 200 using at least one tool 902 to consolidate the stack of the first contact area 202 of the first thermoplastic composite structure 226, the resistance film heating element 210, and the second contact area 206 of the second thermoplastic composite structure 228. In another example, the method continues from 1108 to 1404, at 1404, after the current temperature of the resistance film heating element 210 reaches the desired temperature, welding the first contact area 202 to the second contact area 206 using the resistance film heating element 210 between the first contact area 202 of the first thermoplastic composite structure 226 and the second contact area 206 of the second thermoplastic composite structure 228.

[0055] See again Figures 2A-2B , Figures 5A-5B , Figure 10 and Figure 15In one or more examples, method 1500 for treating polymer-based composite joint 200 (see...) Figure 15 )include Figure 10 Method 1000, and continuing from 1006 to 1502. In this example, the first polymer-based composite structure 204 includes a first thermosetting composite structure 502 having a first contact region 202, while the second polymer-based composite structure 208 includes a second thermosetting composite structure 504 having a second contact region 206. At 1502, a first thermoplastic film 506 is placed on the first thermosetting composite structure 502 above the first contact region 202. A resistance film heating element 210 is placed on the first thermoplastic film 506. At 1504, a second thermoplastic film 508 is placed on the resistance film heating element 210. The second thermosetting composite structure 504 is placed on the second thermoplastic film 508 such that the second contact region 206 of the second thermosetting composite structure 504 is above the second thermoplastic film 508. In another example, method 1500 further includes selectively applying pressure 1506 to polymer-based composite joint 200 to hold a stack of a first contact area 202 of a first thermosetting composite structure 502, a first thermoplastic film 506, a resistance film heating element 210, a second thermoplastic film 508, and a second contact area 206 of a second thermosetting composite structure 504 in place for resistance welding.

[0056] See again Figures 2A-2B , Figures 5A-5B , Figure 6 , Figure 10 , Figure 15 and Figure 16 In one or more examples, method 1600 for treating polymer-based composite joint 200 (see...) Figure 16 )include Figure 10 Method 1000 and Figure 15Method 1500 continues from 1504 to 1602. In this example, the longitudinal form of the resistance film heating element 210 defines a proximal end 218 and a distal end 220. At 1602, an electric line 606 connects from a power source 604 to a first electrical connection 222 at the proximal end 218 of the resistance film heating element 210. At 1604, a return line 608 connects from the power source 604 to a second electrical connection 224 at the distal end 220 of the resistance film heating element 210. At 1606, the power source 604 is activated to provide electrical energy to the resistance film heating element 210, thereby allowing current to flow through the resistance film heating element 210. At 1608, in response to the current, heat is generated at the resistance film heating element 210, and heat radiation is distributed through the polymer-based composite joint 200 to weld the first contact area 202 of the first thermosetting composite structure 502 to the second contact area 206 of the second thermosetting composite structure 504.

[0057] See again Figures 2A-2B , Figures 5A-5B , Figure 10 and Figures 15-17 In one or more examples, method 1700 for treating polymer-based composite joint 200 (see...) Figure 17 )include Figure 10 Method 1000 Figure 15 Method 1500 and Figure 16 Method 1600 continues from 1608 to 1702, where, after reaching a first predetermined temperature of the resistance film heating element, a consolidation force is selectively applied to the polymer-based composite joint 200 to consolidate the stack of the first contact area 202 of the first thermosetting composite structure 502, the first thermoplastic film 506, the resistance film heating element 210, the second thermoplastic film 508, and the second contact area 206 of the second thermosetting composite structure 504. In another example, method 1700 continues from 1608 to 1704, where, after reaching a second predetermined temperature of the resistance film heating element 210, the first contact area 202 is welded to the second contact area 206 using the first thermoplastic film 506, the resistance film heating element 210, and the second thermoplastic film 508 between the first contact area 202 of the first thermosetting composite structure 502 and the second contact area 206 of the second thermosetting composite structure 504. In a further example, method 1700 continues from 1704 to 1706, where, by generating heat at the resistance film heating element 210 to radiate thermal radiation through the polymer-based composite joint 200, the polymer-based composite joint 200 is de-welded, thereby separating the first contact area 202 of the first thermosetting composite structure 502 from the second contact area 206 of the second thermosetting composite structure 504.

[0058] See again Figures 2A-2B , Figure 6 , Figure 10 , Figure 15 , Figure 16 and Figure 18 In one or more examples, method 1800 for treating polymer-based composite joint 200 (see...) Figure 18 )include Figure 10 Method 1000 Figure 15 Method 1500 and Figure 16 Method 1600, and continuing from 1606 to 1802, at 1802, at least one temperature sensor 214 is placed near the resistance film heating element 210, with one or more leads 216 of each temperature sensor 214 exposed externally. At 1804, one or more control lines 612 are connected from the temperature controller 610 to one or more leads 216 of each temperature sensor 214. At 1806, at least one additional line 614 is connected from the temperature controller 610 to the power supply 604. At 1808, the temperature controller 610 is enabled in conjunction with the activation of the power supply 604. At 1810, the current temperature of the resistance film heating element 210 is determined at the temperature controller 610 based at least in part on one or more signals from at least one temperature sensor 214. At 1812, the current temperature of the resistance film heating element 210 is compared with a predetermined temperature distribution of the resistance film heating element 210. At 1814, the current flowing from power supply 604 through resistive film heating element 210 is controlled based on this comparison. Method 1800 continues from 1814, to... Figure 16 1608.

[0059] See again Figures 2A-2B , Figures 5A-5B , Figure 10 , Figure 15 , Figure 16 and Figure 19 In one or more examples, method 1900 for treating polymer-based composite joint 200 (see Figure 19 )include Figure 10 Method 1000 Figure 15 Method 1500 and Figure 16 Method 1600, and continuing from 1608 to 1802, at 1802, after reaching a first predetermined temperature of the resistance film heating element, selectively applies a consolidation force to the polymer-based composite joint 200 to consolidate the stack of the first contact area 202 of the first thermosetting composite structure 502, the first thermoplastic film 506, the resistance film heating element 210, the second thermoplastic film 508, and the second contact area 206 of the second thermosetting composite structure 504. In another example, method 1900 still starts from... Figure 16Continuing from 1608, at 1904, after the second predetermined temperature of the resistance film heating element 210 is reached, the first contact area 202 is welded to the second contact area 206 using a first thermoplastic film 506, a resistance film heating element 210, and a second thermoplastic film 508 between the first contact area 202 of the first thermosetting composite structure 502 and the second contact area 206 of the second thermosetting composite structure 504.

[0060] Overall reference Figures 2A-2B , Figures 5A-5B , Figure 6 , Figure 7 and Figures 20-26 As an example, this disclosure relates to methods 2000, 2100, 2200, 2300, 2400, 2500, and 2600 for treating polymer-based composite joints 200. Figure 2A This is an exploded side view of an example of a polymer-based composite joint 200. Figure 2B yes Figure 2A Top view of polymer-based composite joint 200. Figure 5A This is an exploded side view of yet another example of a polymer-based composite joint 200. Figure 5B yes Figure 5A Top view of polymer-based composite joint 200. Figure 6 This is a functional block diagram of an example of a system 600 for processing polymer-based composite material joints 200. Figure 7 yes Figure 6 A functional diagram of an example of system 600, in which tool 702 is used in conjunction with de-welding of polymer-based composite joints. Figure 20 An example of a method 2000 for treating a polymer-based composite joint 200 is provided. Figure 21 Combination Figure 20 An example of a method 2100 for treating a polymer-based composite joint 200 is provided. Figure 22 Combination Figure 20 An example of a method 2200 for treating a polymer-based composite joint 200 is provided. Figure 23 Combination Figure 20 and Figure 22 An example of a method 2300 for treating a polymer-based composite joint 200 is provided. Figure 24 Combination Figure 20 An example of a method 2400 for treating a polymer-based composite joint 200 is provided. Figure 25 Combination Figure 20 An example of a method 2500 for treating a polymer-based composite joint 200 is provided. Figure 26 Combination Figure 20 and Figure 25 An example of a method 2600 for treating a polymer-based composite joint 200 is provided.

[0061] See again Figures 2A-2B , Figure 6 and Figure 20 In one or more examples, a method 2000 for processing a polymer-based composite joint 200 includes identifying polymer-based composite joints 200 separated by resistance welding 2002. In this embodiment, the polymer-based composite joint 200 includes a first contact region 202 of a first polymer-based composite structure 204, a second contact region 206 of a second polymer-based composite structure 208, and a resistance film heating element 210. The resistance film heating element 210 includes a lignin-based carbonaceous material 212. The resistance film heating element 210 defines a longitudinal shape and is disposed between the first contact region 202 and the second contact region 206. At 2004, a power line 606 is connected from a power source 604 to a first electrical connection 222 at a proximal end 218 of the resistance film heating element 210. At 2006, a return line 608 is connected from the power source 604 to a second electrical connection 224 at a distal end 220 of the resistance film heating element 210. In another example of method 2000, the first polymer-based composite structure 204 includes a first thermoplastic composite structure 226 having a first contact region 202, while the second polymer-based composite structure 208 includes a second thermoplastic composite structure 228 having a second contact region 206. In this example, method 2000 further includes enabling power supply 604 2008 to provide power to resistance film heating element 210, thereby allowing current to flow through resistance film heating element 210. At 2010, in response to the current, heat is generated at resistance film heating element 210, and heat radiation is diffused through polymer-based composite joint (200) to de-weld the first contact region (202) of the first thermoplastic composite structure (226) from the second contact region (206) of the second thermoplastic composite structure (228).

[0062] See again Figures 2A-2B , Figure 7 , Figure 20 and Figure 21 In one or more examples, method 2100 for treating polymer-based composite joint 200 (see...) Figure 21 )include Figure 20Method 2000, and continuing from 2010 to 2102, at 2102, heat is generated at the resistive film heating element 210 to radiate thermal radiation through the polymer-based composite joint 200 to de-weld the polymer-based composite joint 200, thereby separating the first contact area 202 of the first thermoplastic composite structure 226 from the second contact area 206 of the second thermoplastic composite structure 228. In another example, method 2100 further includes separating the first thermoplastic composite structure 226 from the second thermoplastic composite structure 228 2104 using at least one tool 702 to initiate the recycling of the first thermoplastic composite structure 226 and the second thermoplastic composite structure 228.

[0063] See again Figures 2A-2B , Figure 6 , Figure 20 and Figure 22 In one or more examples, method 2200 for treating polymer-based composite joint 200 (see...) Figure 22 )include Figure 20 Method 2000, and continuing from 2006 to 2202. In this example, the first polymer-based composite structure 204 includes a first thermoplastic composite structure 226 having a first contact region 202, while the second polymer-based composite structure 208 includes a second thermoplastic composite structure 228 having a second contact region 206. The polymer-based composite connector 200 also includes at least one temperature sensor 214 embedded in the polymer-based composite connector 200 near the resistance film heating element 210, with one or more leads 216 of each temperature sensor 214 exposed externally. At 2202, one or more control lines 612 are connected from the temperature controller 610 to one or more leads 216 of each temperature sensor 214. At 2204, at least one additional line 614 is connected from the temperature controller 610 to a power supply 604. At 2206, the power supply 604 is enabled to provide electrical energy to the resistance film heating element 210, thereby allowing current to flow through the resistance film heating element 210. At 2208, the temperature controller 610 is activated in conjunction with the activation of the power supply 604. At 2210, in response to the current, heat is generated at the resistance film heating element 210 to radiate heat through the polymer-based composite joint 200, thereby desoldering the first contact area 202 of the first thermoplastic composite structure 226 from the second contact area 206 of the second thermoplastic composite structure 228.

[0064] See again Figures 2A-2B , Figure 6 , Figure 20 , Figure 22 and Figure 23In one or more examples, method 2300 for treating polymer-based composite joint 200 (see...) Figure 23 )include Figure 20 Method 2000 and Figure 22 Method 2200 continues from 2208 to 2302, where at 2302, the current temperature of the resistance film heating element 210 is determined at the temperature controller 610 based at least in part on one or more signals from at least one temperature sensor 214. At 2304, the current temperature of the resistance film heating element 210 is compared with a predetermined temperature distribution of the resistance film heating element 210. At 2306, the current flowing through the resistance film heating element 210 from the power supply 604 is controlled based on this comparison. Method 2300 continues from 2306 to 2210. In another example, method 2300 continues from 2210 to 2308, where at 2308, heat is generated at the resistance film heating element 210 to radiate thermal radiation through the polymer-based composite joint 200 to de-weld the polymer-based composite joint 200, thereby separating the first contact area 202 of the first thermoplastic composite structure 226 from the second contact area 206 of the second thermoplastic composite structure 228.

[0065] See again Figures 2A-2B , Figures 5A-5B , Figure 6 , Figure 7 , Figure 20 and Figure 24 In one or more examples, method 2400 for treating polymer-based composite joint 200 (see...) Figure 24 )include Figure 20Method 2000, and continuing from 2006, up to 2402. In this example, the first polymer-based composite structure 204 includes a first thermosetting composite structure 502 having a first contact region 202, while the second polymer-based composite structure 208 includes a second thermosetting composite structure 504 having a second contact region 206. The polymer-based composite joint 200 also includes a first thermoplastic film 506 disposed between the first contact region 202 of the first thermosetting composite structure 502 and the resistance film heating element 210, and a second thermoplastic film 508 disposed between the second contact region 206 of the resistance film heating element 210 and the second thermosetting composite structure 504. At 2402, a power supply 604 is activated to provide electrical energy to the resistance film heating element 210, thereby allowing current to flow through the resistance film heating element 210. At 2404, in response to an electric current, heat is generated at the resistance film heating element 210 to radiate thermal radiation through the polymer-based composite joint 200, thereby de-welding the first contact area 202 of the first thermosetting composite structure 502 from the second contact area 206 of the second thermosetting composite structure 504. In another example, method 2400 further includes de-welding the polymer-based composite joint 200 2406 by generating heat at the resistance film heating element 210 to radiate thermal radiation through the polymer-based composite joint 200, thereby separating the first contact area 202 of the first thermosetting composite structure 502 from the second contact area 206 of the second thermosetting composite structure 504. In a further example, method 2400 further includes separating the first thermosetting composite structure 502 from the second thermosetting composite structure 504 2408 using at least one tool 702 to initiate the recycling of the first thermosetting composite structure 502 and the second thermosetting composite structure 504.

[0066] See again Figures 2A-2B , Figures 5A-5B , Figure 6 , Figure 20 and Figure 25 In one or more examples, method 2500 for treating polymer-based composite joint 200 (see...) Figure 25 )include Figure 20Method 2000, and continuing from 2006, up to 2502. In this example, the polymer-based composite connector 200 also includes at least one temperature sensor 214 embedded in the polymer-based composite connector 200 near the resistance film heating element 210, with one or more leads 216 of each temperature sensor 214 exposed externally. At 2502, one or more control lines 612 are connected from the temperature controller 610 to one or more leads 216 of each temperature sensor 214. At 2504, at least one additional line 614 is connected from the temperature controller 610 to a power supply 604. At 2506, the power supply 604 is activated to provide electrical energy to the resistance film heating element 210, thereby allowing current to flow through the resistance film heating element 210. At 2508, the temperature controller 610 is activated in conjunction with the activation of the power supply 604. At 2510, in response to the current, heat is generated at the resistive film heating element 210 to radiate heat through the polymer-based composite joint 200, thereby welding the first contact area 202 of the first thermosetting composite structure 502 away from the second contact area 206 of the second thermosetting composite structure 504.

[0067] See again Figures 2A-2B , Figures 5A-5B , Figure 6 , Figure 20 , Figure 25 and Figure 26 In one or more examples, method 2600 for treating polymer-based composite joint 200 (see...) Figure 26 )include Figure 20 Method 2000 and Figure 25 Method 2500 continues from 2508 to 2602, where at 2602, the current temperature of the resistance film heating element 210 is determined at the temperature controller 610 based at least in part on one or more signals from at least one temperature sensor 214. At 2604, the current temperature of the resistance film heating element 210 is compared with a predetermined temperature distribution of the resistance film heating element 210. At 2606, the current flowing through the resistance film heating element 210 from the power supply 604 is controlled based on this comparison. Method 2600 continues from 2606 to... Figure 25 2510. In another example, method 2600 continues from 2510 to 2608, where, by generating heat at the resistive film heating element 210 to radiate thermal radiation through the polymer-based composite joint 200, the polymer-based composite joint 200 is de-welded, thereby separating the first contact area 202 of the first thermosetting composite structure 502 from the second contact area 206 of the second thermosetting composite structure 504.

[0068] Examples of polymer-based composite material joints 200, systems 600 and 800 for processing polymer-based composite material joints 200, and methods 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, and 2600 for processing polymer-based composite material joints 200 may relate to or be used in aircraft manufacturing environments. Although aircraft examples are described, the examples and principles disclosed herein are applicable to other products in the aerospace industry and other industries such as the automotive industry, space industry, construction industry, and other design and manufacturing industries. Therefore, in addition to aircraft, the examples and principles disclosed herein are applicable to the use of various products in the manufacture of various types of vehicles and the construction of various types of buildings.

[0069] The foregoing detailed description refers to the accompanying drawings, which illustrate specific examples described in this disclosure. Other examples with different structures and operations do not depart from the scope of this disclosure. In the different drawings, the same reference numerals may refer to the same features, elements, or components. Throughout this disclosure, any one of a plurality of items may be referred to individually as an item, while a plurality of items may be collectively referred to as an item and may be referred to by the same reference numerals. Furthermore, as used herein, features, elements, components, or steps beginning with the words “a” or “an” should be understood to not exclude multiple features, elements, components, or steps, unless such exclusion is expressly stated.

[0070] The foregoing provides illustrative, non-exhaustive examples of the subject matter of this disclosure, which may, but are not necessarily, claimed. The reference to "example" herein means that one or more features, structures, elements, components, characteristics, and / or operating steps described in connection with that example are included in at least one aspect, implementation, and / or embodiment of the subject matter of this disclosure. Therefore, the phrases "an example," "another example," "one or more examples," and similar terms used throughout this disclosure may, but do not necessarily, refer to the same example. Furthermore, the subject matter characterizing any example may, but does not necessarily include, the subject matter characterizing any other example. Moreover, the subject matter characterizing any example may, but does not necessarily, combine with the subject matter characterizing any other example.

[0071] As used herein, a system, device, apparatus, structure, article, element, component, or hardware "configured to" perform a specified function is indeed capable of performing that specified function without any changes, rather than merely having the potential to perform that specified function only after further modifications. In other words, a system, device, apparatus, structure, article, element, component, or hardware "configured to" perform a specified function is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing that specified function. As used herein, "configured to" indicates existing characteristics of the system, device, structure, article, element, component, or hardware that enable the system, device, structure, article, element, component, or hardware to perform the specified function without further modifications. For the purposes of this disclosure, a system, device, apparatus, structure, article, element, component, or hardware described as "configured to" perform a particular function may additionally or optionally be described as "suitable" and / or "operable to" perform that function.

[0072] Unless otherwise indicated, the terms “first,” “second,” “third,” etc., are used merely as markers and are not intended to impose any order, position, or hierarchy requirements on the items they refer to. Furthermore, references to items such as “second” do not require or exclude the existence of items such as “first” or lower numbered items and / or items such as “third” or higher numbered items.

[0073] As used herein, when used with an item list, the phrase “at least one of…” means that different combinations of one or more of the listed items may be used, and that only one of each item in the list may be required. For example, “at least one of item A, item B, and item C” may include, but is not limited to, item A or item A and item B. This example may also include item A, item B, and item C or item B and item C. In other examples, “at least one of…” may be, for example, non-limitingly, two of item A, one of item B, and ten of item C; four of item B and seven of item C; and other suitable combinations. As used herein, the terms “and / or” and the “ / ” symbol include any and all combinations of one or more related listed items.

[0074] As used herein, the terms “connected,” “linked,” and similar terms refer to two or more elements that are joined, linked, fastened, attached, connected, connected, or otherwise associated with each other (e.g., mechanically, electrically, fluidly, optically, electromagnetically). In various examples, these elements may be directly or indirectly associated. As one example, element A may be directly associated with element B. As another example, element A may be indirectly associated with element B, for example, via another element C. It will be understood that not all associations between the various disclosed elements are necessarily represented. Therefore, links may exist in addition to those shown in the figures.

[0075] As used herein, the term "approximately / approximately" refers to or indicates a condition that is close to, but not exactly, the stated condition, yet still performs the desired function or achieves the desired result. As an example, the term "approximately / approximately" refers to a condition within acceptable predetermined tolerances or precision, such as within 10% of the stated condition. However, the term "approximately" does not exclude a condition that is exactly the stated condition. As used herein, the term "substantially" refers to a condition that is essentially the stated condition that performs the desired function or achieves the desired result.

[0076] As mentioned above Figure 1 , Figures 2A-2B , Figure 3 , Figures 4A-4B , Figures 5A-5B and Figures 6-9 In this context, the terms may represent functional elements, features, or components, but do not necessarily imply any specific structure. Therefore, the illustrated structures may be modified, added to, and / or omitted. Furthermore, those skilled in the art will understand that the terms mentioned above... Figure 1 , Figures 2A-2B , Figure 3 , Figures 4A-4B , Figures 5A-5B and Figures 6-9 Not all elements, features, and / or components described and illustrated herein need to be included in every example, and not all elements, features, and / or components described herein need to be depicted in every illustrative example. Therefore, in Figure 1 , Figures 2A-2B , Figure 3 , Figures 4A-4B , Figures 5A-5B and Figures 6-9 Some of the elements, features, and / or components described and shown herein can be combined in various ways without including Figure 1 , Figures 2A-2B , Figure 3 , Figures 4A-4B , Figures 5A-5B and Figures 6-9 Other features described and illustrated in other accompanying drawings and / or the accompanying disclosure, even if such combinations or combinations are not explicitly stated herein. Similarly, other features, not limited to the examples presented, may be combined with some or all of the features shown and described herein. Unless otherwise expressly stated, the features mentioned above... Figure 1 , Figures 2A-2B , Figure 3 , Figures 4A-4B , Figures 5A-5B and Figures 6-9The illustrative examples shown are not intended to imply any structural limitations on the illustrative examples. Specifically, while an illustrative structure is indicated, it should be understood that this structure can be modified as appropriate. Therefore, modifications, additions, and / or omissions can be made to the illustrated structures. Furthermore, in Figure 1 , Figures 2A-2B , Figure 3 , Figures 4A-4B , Figures 5A-5B and Figures 6-9 In each of these, elements, features, and / or components that serve similar or at least substantially similar purposes are labeled with similar numerals, and such elements, features, and / or components may not be referenced herein. Figure 1 , Figures 2A-2B , Figure 3 , Figures 4A-4B , Figures 5A-5B and Figures 6-9 Each of these will be discussed in detail. Similarly, in Figure 1 , Figures 2A-2B , Figure 3 , Figures 4A-4B , Figures 5A-5B and Figures 6-9 In each of these, not all elements, features and / or parts may be labeled, but for consistency, the reference numbers associated with them may be used herein.

[0077] As mentioned above Figures 10-26 In this context, boxes may represent operations, steps, and / or parts thereof, and the lines connecting the boxes do not imply any particular order or dependency between the operations or their parts. It will be understood that not all dependencies between the various publicly disclosed operations need to be represented. Figures 10-26 The accompanying disclosure describing the operations of the disclosed methods set forth herein should not be construed as requiring a determination of the order in which the operations are to be performed. Rather, while an illustrative order is indicated, it should be understood that the order of operations can be modified as appropriate. Therefore, the operations shown may be modified, added to, and / or omitted, and some operations may be performed in a different order or simultaneously. Furthermore, those skilled in the art will understand that not all described operations need to be performed.

[0078] Furthermore, references to features, advantages, or similar terms used throughout this specification do not imply that all features and advantages achievable with the examples disclosed herein should be or exist in any single example. Rather, terms relating to features and advantages should be understood to mean that a specific feature, advantage, or characteristic described in connection with an example is included in at least one example. Therefore, discussions of features, advantages, and similar terms used throughout this disclosure may, but do not necessarily, refer to the same example.

[0079] Examples of the topics disclosed in this article can be found in, for example... Figure 27 The aircraft manufacturing and service method 2700 shown, and as such Figure 28 The environment of the illustrated aircraft 2800 is described. In one or more examples, the disclosed polymer-based composite joint 200, systems 600 and 800 for processing the polymer-based composite joint 200, and methods 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, and 2600 for processing the polymer-based composite joint 200 can be used in aircraft manufacturing. During pre-production, service method 2700 may include the specifications and design of aircraft 2800 (box 2702) and material procurement (box 2704). During production, the manufacturing of components and sub-assemblies of aircraft 2800 (box 2706) and system integration (box 2708) may be performed. Thereafter, aircraft 2800 may be certified and delivered (box 2710) to be scheduled for service (box 2712). During service, aircraft 2800 may be scheduled for routine maintenance and upkeep (box 2714). Routine maintenance and upkeep may include modifications, reconfigurations, refurbishments, etc., of one or more systems of aircraft 2800.

[0080] Each process of Service Method 2700 may be performed or implemented by a systems integrator, a third party, and / or an operator (e.g., a customer). For the purposes of this description, a systems integrator may include, but is not limited to, any number of aircraft manufacturers and main system subcontractors; a third party may include, but is not limited to, any number of dealers, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, etc.

[0081] like Figure 28 As shown, the aircraft 2800 produced by service method 2700 may include a fuselage 2802 having multiple advanced systems 2804 and an interior 2806. Examples of advanced systems 2804 include one or more propulsion systems 2808, electrical systems 2810, hydraulic systems 2812, and environmental systems 2814. Any number of other systems may be included. Although an aerospace example is shown, the principles disclosed herein are applicable to other industries, such as the automotive industry. Therefore, in addition to aircraft 2800, the principles disclosed herein are also applicable to other vehicles, such as land vehicles, sea vehicles, space vehicles, etc.

[0082] The disclosed polymer-based composite joint 200, systems 600 and 800 for processing the polymer-based composite joint 200, and methods 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, and 2600 for processing the polymer-based composite joint 200 can be used in any one or more of the various stages of manufacturing and servicing method 2700. For example, a component or sub-assembly corresponding to the manufacturing of parts and sub-assemblies (box 2706) can be made or manufactured in a manner similar to that of the components or sub-assemblies produced when the aircraft 2800 enters service (box 2712). Furthermore, one or more examples of systems (one or more), methods (one or more), or combinations thereof can be utilized in the production stages (boxes 2706 and 2708), resulting in, for example, significantly accelerating the assembly of the aircraft 2800 or reducing its cost. Similarly, for example, but not limited to, one or more examples, or combinations thereof, of the systems or methods that can be implemented during the service of the aircraft 2800 (box 2712) and / or during maintenance and upkeep (box 2714).

[0083] The features, advantages, and characteristics of one example described can be combined in any suitable manner in one or more other examples. Those skilled in the art will recognize that the examples described herein can be practiced even where one or more specific features or advantages of a particular example are absent. In other cases, additional features and advantages that may not be present in all examples may be recognized in certain examples. Furthermore, various examples of polymer-based composite joints 200, systems 600 and 800 for processing polymer-based composite joints 200, and methods 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, and 2600 for processing polymer-based composite joints 200 have been shown, but modifications will be apparent to those skilled in the art upon reading the specification. This application includes these modifications and is limited only by the scope of the claims.

[0084] Specifically, the present invention includes the following embodiments: Embodiment 1. A polymer-based composite material joint (200), comprising: The first contact region (202) of the first polymer-based composite material structure (204); The second contact region (206) of the second polymer-based composite structure (208) has a size and shape based on the first contact region (202); and A resistance film heating element (210) comprising a lignin-based carbonaceous material (212) is provided, the resistance film heating element (210) being defined in a longitudinal form and disposed between a first contact area (202) and a second contact area (206), the size and shape of the resistance film heating element (210) being defined based on the first contact area (202) and the second contact area (206), the resistance film heating element (210) being used to join the first polymer-based composite material structure (204) and the second polymer-based composite material structure (208) at the first contact area (202) and the second contact area (206) using a resistance welding process.

[0085] Embodiment 2. The polymer-based composite joint according to Embodiment 1, wherein the first polymer-based composite structure (204) and the second polymer-based composite structure (208) comprise thermoplastic materials.

[0086] Embodiment 3. The polymer-based composite material joint according to Embodiment 1, wherein the lignin-based carbon-containing material (212) includes at least one of lignin-based graphene material, lignin-based graphite material, lignin-based graphene sheet and lignin-based graphite sheet.

[0087] Embodiment 4. The polymer-based composite connector according to Embodiment 1, wherein the resistive film heating element (210) further comprises at least one of the following thicknesses: about 1 nm to about 10 nm, about 10 nm to about 100 nm, about 100 nm to about 1 μm, about 1 μm to about 10 μm, about 10 μm to about 100 μm, and about 100 μm to about 1 mm.

[0088] Embodiment 5. The polymer-based composite connector according to Embodiment 1, wherein the length of the resistive film heating element (210) includes the maximum length based on the conductivity of the resistive film heating element (210) and the desired current through the resistive film heating element (210).

[0089] Embodiment 6. The polymer-based composite joint according to Embodiment 5, wherein when the lengths of the first polymer-based composite structure (204) and the second polymer-based composite structure (208) exceed the maximum length of the resistive film heating element (210), an additional polymer-based composite joint (200) is formed using an additional resistive film heating element (210), thereby completely joining the first polymer-based composite structure (204) and the second polymer-based composite structure (208).

[0090] Embodiment 7. The polymer-based composite material connector according to Embodiment 1, wherein the resistive film heating element (210) further comprises a composite material (302) having a polymer matrix (304), wherein the lignin-based carbon-containing material (212) is blended with the polymer matrix (304).

[0091] Embodiment 8. The polymer-based composite joint according to Embodiment 7, wherein the polymer matrix (304) comprises at least one of the following: polypropylene material, polybutadiene material, polyvinyl alcohol material, high-density polyethylene material, low-density polyethylene material, and linear low-density polyethylene material.

[0092] Embodiment 9. The polymer-based composite material connector according to Embodiment 7, wherein the composite material (302) of the resistive film heating element (210) comprises at least one of the following thicknesses: about 1 nm to about 10 nm, about 10 nm to about 100 nm, about 100 nm to about 1 μm, about 1 μm to about 10 μm, about 10 μm to about 100 μm, and about 100 μm to about 1 mm.

[0093] Embodiment 10. The polymer-based composite material joint according to Embodiment 1, wherein the first contact area (202), the resistive film heating element (210), and the second contact area (206) are in close and continuous contact.

[0094] Embodiment 11. The polymer-based composite joint according to Embodiment 1, wherein the first contact area (202), the resistance film heating element (210) and the second contact area (206) are self-adhesively joined by the resistance welding process.

[0095] Embodiment 12. A polymer-based composite joint according to Embodiment 1, wherein the resistance welding process is used to join the first contact region (202), the resistance film heating element (210), and the second contact region (206) by creating entanglement between polymer chains in the first contact region (202) and the second contact region (206).

[0096] Embodiment 13. A polymer-based composite joint according to Embodiment 1, wherein, in conjunction with the resistance welding process, the first contact region (202), the resistance film heating element (210), and the second contact region (206) are joined by molecular diffusion of polymer chains in the first contact region (202) and the second contact region (206).

[0097] Embodiment 14. The polymer-based composite joint according to Embodiment 1 further comprises: At least one temperature sensor (214) is embedded in the polymer-based composite connector (200) near the resistive film heating element (210), and one or more leads (216) of each temperature sensor (214) are exposed to the outside for connection to the temperature controller (610).

[0098] Embodiment 15. The polymer-based composite joint according to Embodiment 14, wherein the at least one temperature sensor (214) comprises at least one of the following: one or more thermocouples, one or more resistance temperature detectors, and one or more thermistors.

[0099] Embodiment 16. A polymer-based composite material joint according to Embodiment 1, wherein the first polymer-based composite material structure (204) includes a first thermosetting composite material structure (502) having the first contact region (202), and the second polymer-based composite material structure (208) includes a second thermosetting composite material structure (504) having the second contact region (206), the polymer-based composite material joint (200) further includes: A first thermoplastic film (506) is disposed between the first contact area (202) of the first thermosetting composite material structure (502) and the resistance film heating element (210), the size and shape of the first thermoplastic film (506) being determined based on the first contact area (202) and the resistance film heating element (210); and A second thermoplastic film (508) is disposed between the resistance film heating element (210) and the second contact area (206) of the second thermosetting composite material structure (504), the size and shape of the second thermoplastic film (508) being set based on the resistance film heating element (210) and the second contact area (206).

[0100] Embodiment 17. The polymer-based composite joint according to Embodiment 16, wherein the first thermoplastic film (506) and the second thermoplastic film (508) have a thickness of about 20 μm to about 100 μm.

[0101] Embodiment 18. The polymer-based composite joint according to Embodiment 16, wherein the first thermoplastic film (506) and the second thermoplastic film (508) comprise at least one of linear low-density polyethylene, polypropylene, and polyvinyl alcohol.

[0102] Embodiment 19. A polymer-based composite joint according to Embodiment 16, wherein the resistance film heating element (210), the first thermoplastic film (506) and the second thermoplastic film (508) are used to join the first thermosetting composite structure (502) and the second thermosetting composite structure (504) at the first contact area (202) and the second contact area (206) using the resistance welding process.

[0103] Embodiment 20. The polymer-based composite joint according to Embodiment 16, wherein the first contact area (202), the first thermoplastic film (506), the resistance film heating element (210), the second thermoplastic film (508) and the second contact area (206) are in close and continuous contact.

[0104] Embodiment 21. A polymer-based composite material joint according to Embodiment 16, wherein the first contact area (202), the first thermoplastic film (506), the resistance film heating element (210), the second thermoplastic film (508) and the second contact area (206) are self-adhesively joined by the resistance welding process.

[0105] Embodiment 22. A polymer-based composite joint according to Embodiment 16, wherein, in conjunction with the resistance welding process, the first contact area (202), the first thermoplastic film (506), the resistance film heating element (210), the second thermoplastic film (508), and the second contact area (206) are joined by entanglement between the polymer chains of the first contact area (202) and the first thermoplastic film (506) and by entanglement between the polymer chains of the second thermoplastic film (508) and the second contact area (206).

[0106] Embodiment 23. A polymer-based composite joint according to Embodiment 16, wherein, in conjunction with the resistance welding process, the first contact area (202), the first thermoplastic film (506), the second thermoplastic film (508), and the second contact area (206) are joined by molecular diffusion of polymer chains of the first contact area (202), the first thermoplastic film (506), the second thermoplastic film (508), and the second contact area (206).

[0107] Embodiment 24. The polymer-based composite connector according to Embodiment 1, wherein the longitudinal configuration of the resistive film heating element (210) defines a proximal end (218) and a distal end (220), the polymer-based composite connector (200) further comprising: A first electrical connection (222), located at the proximal end (218) of the resistive film heating element (210), is used to receive an electric field line (606) from a power source (604); and The second electrical connection (224), located at the distal end (220) of the resistive film heating element (210), is used to receive a return line (608) from the power source (604).

[0108] Embodiment 25. The polymer-based composite material connector according to Embodiment 24, wherein the first electrical connection (222) and the second electrical connection (224) are composed of at least one of the following: copper material, copper alloy material, copper mesh material, aluminum material, and aluminum alloy material.

[0109] Embodiment 26. The polymer-based composite connector according to Embodiment 24, wherein the power supply (604) comprises a DC power supply.

[0110] Implementation 27. A system (600) for processing polymer-based composite material joints (200), comprising: Polymer-based composite workpiece (602), comprising the polymer-based composite joint (200) as described in embodiment 24; and Power supply (604), wherein power line (606) is connected to the first electrical connection (222) and return line (608) is connected to the second electrical connection (224).

[0111] Embodiment 28. According to the system of Embodiment 27, the polymer-based composite joint (200) further comprises: At least one temperature sensor (214) is embedded in the polymer-based composite connector (200) near the resistive film heating element (210), and one or more leads (216) of each temperature sensor (214) are exposed to the outside; and The system (600) further includes: A temperature controller (610) wherein one or more control lines (612) are connected to one or more leads (216) of the at least one temperature sensor (214) to determine the current temperature of the resistive film heating element (210), and at least one additional line (614) is connected to the power supply (604) to control the current flowing through the resistive film heating element (210) in response to the current temperature.

[0112] Embodiment 29. The system according to Embodiment 28, wherein after the third predetermined temperature of the resistive film heating element (210) is reached, the first contact area (202) of the first polymer-based composite material structure (204) is de-welded from the second contact area (206) of the second polymer-based composite material structure (208).

[0113] Implementation 30. The system according to implementation 28 further includes: At least one tool (702) is used to selectively separate the first contact area (202) of the first polymer-based composite structure (204) from the second contact area (206) of the second polymer-based composite structure (208) after the first contact area (202) and the second contact area (206) have been de-welded.

[0114] Implementation 31. The system according to implementation 30, wherein the at least one tool (702) includes at least one of the following: one or more robot end effectors, one or more elevators, and one or more cranes.

[0115] Embodiment 32. The system according to Embodiment 27, wherein the first polymer-based composite material structure (204) comprises a first thermosetting composite material structure (502) having the first contact region (202), and the second polymer-based composite material structure (208) comprises a second thermosetting composite material structure (504) having the second contact region (206), and the polymer-based composite material joint (200) further comprises: A first thermoplastic film (506) is disposed between the first contact area (202) of the first thermosetting composite material structure (502) and the resistance film heating element (210), the size and shape of the first thermoplastic film (506) being determined based on the first contact area (202) and the resistance film heating element (210); and A second thermoplastic film (508) is disposed between the resistance film heating element (210) and the second contact area (206) of the second thermosetting composite material structure (504), the size and shape of the second thermoplastic film (508) being set based on the resistance film heating element (210) and the second contact area (206).

[0116] Embodiment 33. According to the system of Embodiment 32, the polymer-based composite joint (200) further comprises: At least one temperature sensor (214) is embedded in the polymer-based composite connector (200) near the resistive film heating element (210), and one or more leads (216) of each temperature sensor (214) are exposed to the outside; and The system (600) further includes: A temperature controller (610) wherein one or more control lines (612) are connected to one or more leads (216) of the at least one temperature sensor (214) to determine the current temperature of the resistive film heating element (210), and at least one additional line (614) is connected to the power supply (604) to control the current flowing through the resistive film heating element (210) in response to the current temperature.

[0117] Implementation 34. According to the system of Implementation 33, after the third predetermined temperature of the resistance film heating element (210) is reached, the first contact area (202) of the first thermosetting composite material structure (502) is de-welded from the second contact area (206) of the second thermosetting composite material structure (504).

[0118] Implementation method 35. The system according to implementation method 33 further includes: At least one tool (702) is used to selectively separate the first contact area (202) of the first thermosetting composite structure (502) from the second contact area (206) of the second thermosetting composite structure (504) after the first contact area (202) and the second contact area (206) have been de-welded.

[0119] Implementation 36. A system (800) for processing polymer-based composite material joints (200), comprising: A polymer-based composite workpiece (802) comprising the polymer-based composite joint (200) described in Embodiment 1.

[0120] Implementation method 37. The system according to implementation method 36 further includes: At least one tool (902) is used to selectively apply pressure to the polymer-based composite joint (200) to hold the stack of the first contact area (202) of the first polymer-based composite structure (204), the resistance film heating element (210), and the second contact area (206) of the second polymer-based composite structure (208) in place for the resistance welding process.

[0121] Embodiment 38. The system according to Embodiment 37, wherein the at least one tool (902) includes at least one of the following: one or more grippers, one or more locking clamps, and one or more robot end effectors.

[0122] Embodiment 39. The system according to Embodiment 36, wherein the longitudinal configuration of the resistive film heating element (210) defines a proximal end (218) and a distal end (220), and the polymer-based composite connector (200) further comprises: The first electrical connection (222) at the proximal end (218) of the resistive film heating element (210); and The second electrical connection (224) at the distal end (220) of the resistive film heating element (210); and The system (800) further includes: Power supply (604), wherein the power line (606) is connected to the first electrical connection (222) and the return line (608) is connected to the second electrical connection (224).

[0123] Embodiment 40. According to the system of Embodiment 39, the polymer-based composite joint (200) further comprises: At least one temperature sensor (214) is embedded in the polymer-based composite connector (200) near the resistive film heating element (210), and one or more leads (216) of each temperature sensor (214) are exposed to the outside; and The system (800) further includes: A temperature controller (610) wherein one or more control lines (612) are connected to one or more leads (216) of the at least one temperature sensor (214) to determine the current temperature of the resistive film heating element (210), and at least one additional line (614) is connected to the power supply (604) to control the current flowing through the resistive film heating element (210) in response to the current temperature.

[0124] Implementation 41. The system according to implementation 40 further includes: At least one tool (902) is used to selectively apply a consolidation force to the polymer-based composite joint (200) after a first predetermined temperature of the resistive film heating element (210) is reached, to consolidate the stack of the first contact area (202) of the first polymer-based composite structure (204), the resistive film heating element (210), and the second contact area (206) of the second polymer-based composite structure (208).

[0125] Embodiment 42. The system according to Embodiment 41, wherein the at least one tool (902) includes at least one of the following: one or more grippers, one or more locking clamps, and one or more robot end effectors.

[0126] Embodiment 43. The system according to Embodiment 40, wherein after the second predetermined temperature of the resistive film heating element (210) is reached, the first contact area (202) is welded to the second contact area (206) using the resistive film heating element (210) between the first contact area (202) of the first polymer-based composite structure (204) and the second contact area (206) of the second polymer-based composite structure (208).

[0127] Embodiment 44. The system according to Embodiment 36, wherein the first polymer-based composite material structure (204) comprises a first thermosetting composite material structure (502) having the first contact region (202), and the second polymer-based composite material structure (208) comprises a second thermosetting composite material structure (504) having a second contact region (206), and the polymer-based composite material joint (200) further comprises: A first thermoplastic film (506) is disposed between the first contact area (202) of the first thermosetting composite material structure (502) and the resistance film heating element (210), the size and shape of the first thermoplastic film (506) being determined based on the first contact area (202) and the resistance film heating element (210); and A second thermoplastic film (508) is disposed between the resistance film heating element (210) and the second contact area (206) of the second thermosetting composite material structure (504), the size and shape of the second thermoplastic film (508) being set based on the resistance film heating element (210) and the second contact area (206).

[0128] Implementation method 45. The system according to implementation method 44 further includes: At least one tool (902) is used to selectively apply pressure to the polymer-based composite joint (200) to hold in place a stack of the first contact area (202) of the first thermosetting composite structure (502), the first thermoplastic film (506), the resistance film heating element (210), the second thermoplastic film (508), and the second contact area (206) of the second thermosetting composite structure (504) for the resistance welding process.

[0129] Embodiment 46. The system according to Embodiment 44, wherein the longitudinal configuration of the resistive film heating element (210) defines a proximal end (218) and a distal end (220), and the polymer-based composite connector (200) further comprises: The first electrical connection (222) at the proximal end (218) of the resistive film heating element (210); and The second electrical connection (224) at the distal end (220) of the resistive film heating element (210); and The system (800) further includes: Power supply (604), wherein the power line (606) is connected to the first electrical connection (222) and the return line (608) is connected to the second electrical connection (224).

[0130] Embodiment 47. According to the system of Embodiment 46, the polymer-based composite joint (200) further comprises: At least one temperature sensor (214) is embedded in the polymer-based composite connector (200) near the resistive film heating element (210), and one or more leads (216) of each temperature sensor (214) are exposed externally; and The system (800) further includes: A temperature controller (610) wherein one or more control lines (612) are connected to one or more leads (216) of the at least one temperature sensor (214) to determine the current temperature of the resistive film heating element (210), and at least one additional line (614) is connected to the power supply (604) to control the current flowing through the resistive film heating element (210) in response to the current temperature.

[0131] Implementation 48. The system according to implementation 47 further includes: At least one tool (902) is used to selectively apply a consolidation force to the polymer-based composite joint (200) after the first predetermined temperature of the resistive film heating element (210) is reached, to consolidate the stack of the first contact area (202) of the first thermosetting composite structure (502), the first thermoplastic film (506), the resistive film heating element (210), the second thermoplastic film (508), and the second contact area (206) of the second thermosetting composite structure (504).

[0132] Embodiment 49. The system according to Embodiment 47, wherein after the second predetermined temperature of the resistance film heating element (210) is reached, the first contact area (202) is welded to the second contact area (206) using the first thermoplastic film (506) between the first contact area (202) of the first thermosetting composite material structure (502) and the second contact area (206) of the second thermosetting composite material structure (504), the resistance film heating element (210) and the second thermoplastic film (508).

[0133] Embodiment 50. A method (1000) for treating a polymer-based composite joint (200), comprising: Identify (1002) the first polymer-based composite structure (204) and the second polymer-based composite structure (208) to be joined by resistance welding. A resistance film heating element (210) is placed (1004) on the first polymer-based composite material structure (204) above a first contact area (202) of the first polymer-based composite material structure (204), the resistance film heating element (210) comprising a lignin-based carbon-containing material (212) and defined in a longitudinal shape; and The second polymer-based composite structure (208) is placed (1006) on the resistance film heating element (210) such that the second contact area (206) of the second polymer-based composite structure (208) is aligned with the first contact area (202) of the first polymer-based composite structure (204), the first contact area (202), the resistance film heating element (210) and the second contact area (206) defining a stack for resistance welding at the polymer-based composite joint (200).

[0134] Embodiment 51. The method according to Embodiment 50, wherein the first polymer-based composite material structure (204) and the second polymer-based composite material structure (208) comprise thermoplastic materials.

[0135] Embodiment 52. According to the method of Embodiment 50, the lignin-based carbon-containing material (212) includes at least one of the following: lignin-based graphene material, lignin-based graphite material, lignin-based graphene sheet, and lignin-based graphite sheet.

[0136] Embodiment 53. According to the method of Embodiment 50, wherein the resistive film heating element (210) further comprises a composite material (302) having a polymer matrix (304), wherein the lignin-based carbon-containing material (212) is blended with the polymer matrix (304).

[0137] Implementation 54. The method (1000) according to implementation 50 further includes: Using at least one tool (902), pressure (1008) is selectively applied to the polymer-based composite joint (200) to hold the stack of the first contact area (202) of the first polymer-based composite structure (204), the resistance film heating element (210), and the second contact area (206) of the second polymer-based composite structure (208) in place for resistance welding.

[0138] Embodiment 55. According to the method of Embodiment 54, wherein the first contact area (202), the resistive film heating element (210) and the second contact area (206) are in close and continuous contact.

[0139] Embodiment 56. The method (1100) according to Embodiment 50, wherein the first polymer-based composite material structure (204) comprises a first thermoplastic composite material structure (226) having the first contact region (202), and the second polymer-based composite material structure (208) comprises a second thermoplastic composite material structure (228) having the second contact region (206), the method further comprising: A power line (606) is connected (1102) from a power source (604) to a first electrical connection (222) at the proximal end (218) of the resistive film heating element (210). The return line (608) is connected (1104) from the power source (604) to the second electrical connection (224) at the far end (220) of the resistive film heating element (210). Enable (1106) the power supply (604) to provide power to the resistive film heating element (210), thereby allowing current to flow through the resistive film heating element (210); and In response to the current, heat (1108) is generated at the resistive film heating element (210) to radiate heat through the polymer-based composite joint (200), thereby welding the first contact area (202) of the first thermoplastic composite structure (226) to the second contact area (206) of the second thermoplastic composite structure (228).

[0140] Implementation 57. The method (1200) according to implementation 56 further includes: After the first predetermined temperature of the resistive film heating element (210) is reached, a (1202) consolidation force is selectively applied to the polymer-based composite joint (200) using at least one tool (902) to consolidate the stack of the first contact area (202) of the first thermoplastic composite structure (226), the resistive film heating element (210), and the second contact area (206) of the second thermoplastic composite structure (228).

[0141] Implementation 58. The method (1200) according to implementation 56 further includes: After the second predetermined temperature of the resistance film heating element (210) is reached, the first contact area (202) is welded (1204) to the second contact area (206) using the resistance film heating element (210) between the first contact area (202) of the first thermoplastic composite structure (226) and the second contact area (206) of the second thermoplastic composite structure (228).

[0142] Implementation method 59. The method according to implementation method 58 further includes: By generating heat at the resistive film heating element (210) to radiate heat radiation through the polymer-based composite joint (200) to de-weld (1206), the first contact area (202) of the first thermoplastic composite structure (226) is separated from the second contact area (206) of the second thermoplastic composite structure (228).

[0143] Implementation 60. The method (1300) according to implementation 56 further includes: At least one temperature sensor (214) is placed (1302) near the resistive film heating element (210), with one or more leads (216) of each temperature sensor (214) exposed to the outside; Connect one or more control lines (612) from the temperature controller (610) (1304) to the one or more leads (216) of each temperature sensor (214). Connect at least one additional wire (614) from the temperature controller (610) (1306) to the power supply (604). The temperature controller (610) is enabled (1308) in conjunction with the activation of the power supply (604). The current temperature of the resistive film heating element (210) is determined (1310) at the temperature controller (610) based at least in part on one or more signals from the at least one temperature sensor (214); The current temperature of the resistive film heating element (210) is compared with the predetermined temperature distribution of the resistive film heating element (210) (1312); and The current flowing from the power source (604) through the resistive film heating element (210) is based on the comparison control (1314).

[0144] Implementation method 61. The method (1400) according to implementation method 60 further includes: After the current temperature of the resistive film heating element (210) reaches the desired temperature, a (1402) consolidation force is selectively applied to the polymer-based composite joint (200) using at least one tool (902) to consolidate the stack of the first contact area (202) of the first thermoplastic composite structure (226), the resistive film heating element (210), and the second contact area (206) of the second thermoplastic composite structure (228).

[0145] Implementation method 62. The method (1400) according to implementation method 60 further includes: After the current temperature of the resistance film heating element (210) reaches the desired temperature, the first contact area (202) is welded (1404) to the second contact area (206) using the resistance film heating element (210) between the first contact area (202) of the first thermoplastic composite structure (226) and the second contact area (206) of the second thermoplastic composite structure (228).

[0146] Embodiment 63. The method (1500) according to Embodiment 50, wherein the first polymer-based composite material structure (204) comprises a first thermosetting composite material structure (502) having the first contact region (202), and the second polymer-based composite material structure (208) comprises a second thermosetting composite material structure (504) having the second contact region (206), the method further comprising: A first thermoplastic film (506) is placed (1502) on the first thermosetting composite material structure (502) above the first contact area (202), and the resistive film heating element (210) is placed on the first thermoplastic film (506); and The second thermoplastic film (508) is placed (1504) on the resistance film heating element (210), and the second thermosetting composite material structure (504) is placed on the second thermoplastic film (508) such that the second contact area (206) of the second thermosetting composite material structure (504) is above the second thermoplastic film (508).

[0147] Implementation method 64. The method (1500) according to implementation method 63 further includes: Selectively apply (1506) pressure to the polymer-based composite joint (200) to hold the stack of the first contact area (202) of the first thermosetting composite structure (502), the first thermoplastic film (506), the resistance film heating element (210), the second thermoplastic film (508), and the second contact area (206) of the second thermosetting composite structure (504) in place for resistance welding.

[0148] Embodiment 65. The method (1600) according to Embodiment 63, wherein the longitudinal configuration of the resistive film heating element (210) defines a proximal end (218) and a distal end (220), the method further comprising: A power line (606) is connected (1602) from a power source (604) to a first electrical connection (222) at the proximal end (218) of the resistive film heating element (210). The return line (608) is connected (1604) from the power source (604) to the second electrical connection (224) at the distal end (220) of the resistive film heating element (210). Enable (1606) the power supply (604) to provide power to the resistive film heating element (210), thereby allowing current to flow through the resistive film heating element (210); and In response to the current, heat (1608) is generated at the resistive film heating element (210) to radiate heat through the polymer-based composite joint (200), thereby welding the first contact area (202) of the first thermosetting composite structure (502) to the second contact area (206) of the second thermosetting composite structure (504).

[0149] Implementation 66. The method (1700) according to implementation 65 further includes: After the first predetermined temperature of the resistive film heating element (210) is reached, a (1702) consolidation force is selectively applied to the polymer-based composite material joint (200) to consolidate the stack of the first contact area (202) of the first thermosetting composite material structure (502), the first thermoplastic film (506), the resistive film heating element (210), the second thermoplastic film (508), and the second contact area (206) of the second thermosetting composite material structure (504).

[0150] Implementation 67. The method (1700) according to implementation 65 further includes: After the second predetermined temperature of the resistance film heating element (210) is reached, the first contact area (202) is welded (1704) to the second contact area (206) using the first thermoplastic film (506) between the first contact area (202) of the first thermosetting composite material structure (502) and the second contact area (206) of the second thermosetting composite material structure (504), the resistance film heating element (210) and the second thermoplastic film (508).

[0151] Implementation method 68. The method (1700) according to implementation method 67 further includes: Heat is generated at the resistive film heating element (210) to spread thermal radiation through the polymer-based composite joint (200) to de-weld (1706), thereby separating the first contact area (202) of the first thermosetting composite structure (502) from the second contact area (206) of the second thermosetting composite structure (504).

[0152] Implementation method 69. The method (1800) according to implementation method 65 further includes: At least one temperature sensor (214) is placed (1802) near the resistive film heating element (210), with one or more leads (216) of each temperature sensor (214) exposed to the outside; Connect one or more control lines (612) from the temperature controller (610) (1804) to the one or more leads (216) of each temperature sensor (214). Connect at least one additional wire (614) from the temperature controller (610) (1806) to the power supply (604). The temperature controller (610) is enabled (1808) in conjunction with the activation of the power supply (604). The current temperature of the resistive film heating element (210) is determined (1810) at the temperature controller (610) based at least in part on one or more signals from the at least one temperature sensor (214); The current temperature of the resistive film heating element (210) is compared with the predetermined temperature distribution of the resistive film heating element (210) (1812); and The current flowing from the power source (604) through the resistive film heating element (210) is based on the comparison control (1814).

[0153] Implementation 70. The method (1900) according to implementation 69 further includes: After the first predetermined temperature of the resistive film heating element (210) is reached, a (1902) consolidation force is selectively applied to the polymer-based composite material joint (200) to consolidate the stack of the first contact area (202) of the first thermosetting composite material structure (502), the first thermoplastic film (506), the resistive film heating element (210), the second thermoplastic film (508), and the second contact area (206) of the second thermosetting composite material structure (504).

[0154] Implementation method 71. The method (1900) according to implementation method 69 further includes: After the second predetermined temperature of the resistance film heating element (210) is reached, the first contact area (202) is welded (1904) to the second contact area (206) using the first thermoplastic film (506) between the first contact area (202) of the first thermosetting composite material structure (502) and the second contact area (206) of the second thermosetting composite material structure (504), the resistance film heating element (210) and the second thermoplastic film (508).

[0155] Implementation 72. A method (2000) for treating a polymer-based composite joint (200), comprising: Identify (2002) a polymer-based composite joint (200) to be separated by resistance welding, the polymer-based composite joint (200) comprising a first contact area (202) of a first polymer-based composite structure (204), a second contact area (206) of a second polymer-based composite structure (208), and a resistance film heating element (210) comprising a lignin-based carbon-containing material (212), the resistance film heating element (210) defining a longitudinal form and disposed between the first contact area (204) and the second contact area (206); Connect the power line (606) from the power source (604) to the first electrical connection (222) at the proximal end (218) of the resistive film heating element (210); and The return line (608) is connected (2006) from the power source (604) to the second electrical connection (224) at the far end (220) of the resistive film heating element (210).

[0156] Embodiment 73. The method (2000) according to Embodiment 72, wherein the first polymer-based composite material structure (204) comprises a first thermoplastic composite material structure (226) having the first contact region (202), and the second polymer-based composite material structure (208) comprises a second thermoplastic composite material structure (228) having the second contact region (206), the method further comprising: Enable (2008) the power supply (604) to provide power to the resistive film heating element (210), thereby allowing current to flow through the resistive film heating element (210); and In response to the current, heat is generated (2010) at the resistive film heating element (210) to radiate heat through the polymer-based composite joint (200), thereby desoldering the first contact area (202) of the first thermoplastic composite structure (226) from the second contact area (206) of the second thermoplastic composite structure (228).

[0157] Implementation 74. The method (2100) according to implementation 73 further includes: By generating heat at the resistive film heating element (210) to radiate heat radiation through the polymer-based composite joint (200) to de-weld (2102), the first contact area (202) of the first thermoplastic composite structure (226) is separated from the second contact area (206) of the second thermoplastic composite structure (228).

[0158] Implementation 75. The method (2100) according to implementation 74 further includes: Using at least one tool (702), the first thermoplastic composite structure (226) is separated from the second thermoplastic composite structure (228) (2104) to initiate the recycling of the first thermoplastic composite structure (226) and the second thermoplastic composite structure (228).

[0159] Embodiment 76. The method (2200) according to Embodiment 72, wherein the first polymer-based composite material structure (204) comprises a first thermoplastic composite material structure (226) having the first contact region (202), and the second polymer-based composite material structure (208) comprises a second thermoplastic composite material structure (228) having the second contact region (206), wherein the polymer-based composite material joint (200) further comprises at least one temperature sensor (214), the at least one temperature sensor (214) being embedded in the polymer-based composite material joint (200) near the resistive film heating element (210), wherein one or more leads (216) of each temperature sensor (214) are exposed externally, the method further comprising: Connect one or more control lines (612) from the temperature controller (610) (2202) to the one or more leads (216) of each temperature sensor (214). Connect at least one additional wire (614) from the temperature controller (610) (2204) to the power supply (604). The power supply (604) is activated (2206) to provide power to the resistive film heating element (210), thereby allowing current to flow through the resistive film heating element (210). The temperature controller (610) is enabled (2208) in conjunction with the activation of the power supply (604); and In response to the current, heat is generated at the resistive film heating element (210) to radiate heat through the polymer-based composite joint (200), thereby desoldering the first contact area (202) of the first thermoplastic composite structure (226) from the second contact area (206) of the second thermoplastic composite structure (228).

[0160] Implementation 77. The method (2300) according to implementation 76 further includes: The current temperature of the resistive film heating element (210) is determined (2302) at the temperature controller (610) based at least in part on one or more signals from the at least one temperature sensor (214); Compare the current temperature of the resistive film heating element (210) with the predetermined temperature distribution of the resistive film heating element (210) (2304); and The current flowing from the power source (604) through the resistive film heating element (210) is based on the comparison control (2306).

[0161] Implementation 78. The method (2300) according to implementation 76 further includes: By generating heat at the resistive film heating element (210) to radiate heat radiation through the polymer-based composite joint (200) to de-weld (2308), the first contact area (202) of the first thermoplastic composite structure (226) is separated from the second contact area (206) of the second thermoplastic composite structure (228).

[0162] Embodiment 79. According to the method of Embodiment 72, wherein the first polymer-based composite material structure (204) includes a first thermosetting composite material structure (502) having the first contact area (202), and the second polymer-based composite material structure (208) includes a second thermosetting composite material structure (504) having the second contact area (206), and the polymer-based composite material joint (200) further includes a first thermoplastic film (506) disposed between the first contact area (202) of the first thermosetting composite material structure (502) and the resistance film heating element (210), and a second thermoplastic film (508) disposed between the resistance film heating element (210) and the second contact area (206) of the second thermosetting composite material structure (504).

[0163] Implementation method 80. The method (2400) according to implementation method 79 further includes: Enable (2402) the power supply (604) to provide power to the resistive film heating element (210), thereby allowing current to flow through the resistive film heating element (210); and In response to the current, heat (2404) is generated at the resistive film heating element (210) to radiate heat through the polymer-based composite joint (200), thereby desoldering the first contact area (202) of the first thermosetting composite structure (502) from the second contact area (206) of the second thermosetting composite structure (504).

[0164] Implementation method 81. The method (2400) according to implementation method 80 further includes: By generating heat at the resistive film heating element (210) to radiate heat radiation through the polymer-based composite joint (200) to de-weld (2406), the first contact area (202) of the first thermosetting composite structure (502) is separated from the second contact area (206) of the second thermosetting composite structure (504).

[0165] Implementation method 82. The method (2400) according to implementation method 81 further includes: Using at least one tool (702), the first thermoset composite structure (502) is separated (2408) from the second thermoset composite structure (504) to initiate the recycling of the first thermoset composite structure (502) and the second thermoset composite structure (504).

[0166] Embodiment 83. The method (2500) according to Embodiment 79, wherein the polymer-based composite connector (200) further comprises at least one temperature sensor (214), the at least one temperature sensor (214) being embedded in the polymer-based composite connector (200) near the resistive film heating element (210), one or more leads (216) of each temperature sensor (214) being exposed externally, the method further comprising: Connect one or more control lines (612) from the temperature controller (610) (2502) to the one or more leads (216) of each temperature sensor (214). Connect at least one additional wire (614) from the temperature controller (610) (2504) to the power supply (604). Enable (2506) the power supply (604) to provide power to the resistive film heating element (210), thereby allowing current to flow through the resistive film heating element (210). The temperature controller (610) is enabled (2508) in conjunction with the activation of the power supply (604); and In response to the current, heat (2510) is generated at the resistive film heating element (210) to radiate heat through the polymer-based composite joint (200), thereby desoldering the first contact area (202) of the first thermosetting composite structure (502) from the second contact area (206) of the second thermosetting composite structure (504).

[0167] Implementation method 84. The method (2600) according to implementation method 83 further includes: The current temperature of the resistive film heating element (210) is determined (2602) at the temperature controller (610) based at least in part on one or more signals from the at least one temperature sensor (214); Compare the current temperature of the resistive film heating element (210) with the predetermined temperature distribution of the resistive film heating element (210) (2604); and The current flowing from the power source (604) through the resistive film heating element (210) is based on the comparison control (2606).

[0168] Implementation method 85. The method (2600) according to implementation method 83 further includes: By generating heat at the resistive film heating element (210) to radiate heat radiation through the polymer-based composite joint (200) to de-weld (2608), the first contact area (202) of the first thermosetting composite structure (502) is separated from the second contact area (206) of the second thermosetting composite structure (504).

Claims

1. A polymer-based composite material joint (200), comprising: The first contact region (202) of the first polymer-based composite material structure (204); The second contact region (206) of the second polymer-based composite material structure (208) has a size and shape based on the first contact region (202); and A resistance film heating element (210) comprising a lignin-based carbonaceous material (212) is provided, the resistance film heating element (210) being defined in a longitudinal form and disposed between a first contact area (202) and a second contact area (206), the size and shape of the resistance film heating element (210) being defined based on the first contact area (202) and the second contact area (206), the resistance film heating element (210) being used to join the first polymer-based composite material structure (204) and the second polymer-based composite material structure (208) at the first contact area (202) and the second contact area (206) using a resistance welding process.

2. The polymer-based composite material joint according to claim 1, wherein the first polymer-based composite material structure (204) and the second polymer-based composite material structure (208) comprise thermoplastic materials.

3. The polymer-based composite material joint according to claim 1, wherein the lignin-based carbon-containing material (212) includes at least one of lignin-based graphene material, lignin-based graphite material, lignin-based graphene sheet and lignin-based graphite sheet.

4. The polymer-based composite connector according to claim 1, wherein the resistive film heating element (210) further comprises at least one of the following thicknesses: about 1 nm to about 10 nm, about 10 nm to about 100 nm, about 100 nm to about 1 μm, about 1 μm to about 10 μm, about 10 μm to about 100 μm, and about 100 μm to about 1 mm.

5. The polymer-based composite connector according to claim 1, wherein the length of the resistive film heating element (210) includes the maximum length based on the conductivity of the resistive film heating element (210) and the desired current through the resistive film heating element (210).

6. The polymer-based composite joint according to claim 5, wherein when the lengths of the first polymer-based composite structure (204) and the second polymer-based composite structure (208) exceed the maximum length of the resistive film heating element (210), an additional polymer-based composite joint (200) is formed using an additional resistive film heating element (210), thereby completely joining the first polymer-based composite structure (204) and the second polymer-based composite structure (208).

7. The polymer-based composite material connector according to claim 1, wherein the resistive film heating element (210) further comprises a composite material (302) having a polymer matrix (304), wherein the lignin-based carbon-containing material (212) is blended with the polymer matrix (304).

8. The polymer-based composite joint according to claim 7, wherein the polymer matrix (304) comprises at least one of the following: polypropylene, polybutadiene, polyvinyl alcohol, high-density polyethylene, low-density polyethylene and linear low-density polyethylene.

9. The polymer-based composite material connector according to claim 7, wherein the composite material (302) of the resistive film heating element (210) comprises at least one of the following thicknesses: about 1 nm to about 10 nm, about 10 nm to about 100 nm, about 100 nm to about 1 μm, about 1 μm to about 10 μm, about 10 μm to about 100 μm, and about 100 μm to about 1 mm.

10. The polymer-based composite material joint according to claim 1, wherein the first contact area (202), the resistive film heating element (210), and the second contact area (206) are in close and continuous contact.

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