Ultrasonic composite riveting method for continuous fiber reinforced thermoplastic composites and metals

Abstract

This invention discloses an ultrasonic composite riveting method for continuous fiber reinforced thermoplastic composite materials and metals. Before welding, the metal plate is subjected to surface laser additive and subtractive processing to form grooves and spikes on the metal surface, resulting in high processing efficiency. For the thermoplastic composite plate, thermal piercing technology is used, which has little impact on the woven fibers. Then, ultrasonic composite riveting is used to connect the two plates. This method combines the advantages of ultrasonic welding and self-fusion riveting, and has better comprehensive properties such as tensile shear resistance, peel resistance, and torsion resistance, which greatly improves the welding quality of composite materials and dissimilar metal materials. This method is efficient, fast, and low-cost, and solves the problem of the lack of a widely applicable connection technology in the field of metal-fiber reinforced thermoplastic composite material connection.

Description

Technical Field

[0001] This invention belongs to the field of dissimilar material joining technology, specifically relating to an ultrasonic composite riveting method for continuous fiber reinforced thermoplastic composite materials and metals. Background Technology

[0002] Fiber-reinforced thermoplastic composites are widely used in various structures of missiles, rockets, satellites, and spacecraft systems due to their advantages such as light weight, high modulus, high strength, designability, high temperature resistance, excellent thermal stability, fatigue resistance, corrosion resistance, and good processability. Among them, long fibers and continuous fibers have better mechanical and thermal conductivity properties. From an application perspective, due to the requirements of integrated manufacturing processes, high-performance composite materials are usually made of continuous carbon fibers.

[0003] While fiber-reinforced composites offer many advantages, their strength, durability, and stiffness at high temperatures are still somewhat weaker compared to traditional metal materials. Because metals possess advantages that fiber-reinforced composites lack, they cannot be completely replaced by composites. This suggests that further research is needed into the bonding technology of hybrid metal-composite structures.

[0004] The differences in the thermal, chemical, and mechanical properties of dissimilar materials make the joining of these dissimilar combinations complex. Traditionally, metals and fiber-reinforced composites are joined using adhesives, mechanical riveting (such as rivets and bolts), and hybrid bolt-bonded composite joints. However, bonded joints are prone to thermal degradation due to factors such as moisture, humidity, and high temperatures. Disassembly is difficult and, because it is an irreversible process, can lead to material damage. Bolting connections also have many drawbacks, such as stress concentration in fastener holes and delamination and micro-buckling caused by drilling, which reduce the strength and performance of the joint. Welding technology can solve both adhesive and mechanical joining problems. It facilitates the large-scale production of joints between metals and composites. However, the search for an optimal process for joining metals and composites remains to be explored. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing an ultrasonic composite riveting and welding method for continuous fiber reinforced thermoplastic composite materials and metals. This method combines the advantages of riveting and ultrasonic welding to achieve a dissimilar material joining technology that is efficient, energy-saving, fast, low-cost, with high strength and quality, excellent tensile and shear resistance, peel resistance, and torsional resistance, aesthetically pleasing joints, and easy to automate and control. This method is used to solve the technical problem of low applicability of metal-fiber reinforced thermoplastic composite material joining.

[0006] The present invention adopts the following technical solution:

[0007] An ultrasonic composite riveting method for continuous fiber-reinforced thermoplastic composites and metals includes the following steps:

[0008] S1. Perform hot puncture treatment on the thermoplastic composite board, perform surface laser metal addition and subtraction processing on the metal plate, and then drill a hole in the center of the welding area of ​​the metal plate.

[0009] S2. The thermoplastic composite material plate obtained in step S1 is ultrasonically composite welded to the metal plate. The composite welding is achieved by resin melting, spike protrusion nailing and rivet riveting.

[0010] Specifically, in step S1, the hot puncture of the thermoplastic composite plate is performed as follows:

[0011] The thermoplastic composite material board was cleaned with alcohol, air-dried, and then placed in a temperature-controlled chamber at 130–150°C for puncture.

[0012] Furthermore, the matrix of the thermoplastic composite sheet includes polyethylene, polyetheretherketone, polyphenylene sulfide, and polyethylene terephthalate.

[0013] Specifically, in step S1, the laser metal addition and subtraction processing is as follows:

[0014] Without powder coating, a laser beam is used to process grooves on the surface of a metal plate; then, with powder coating, spikes are printed onto the metal plate.

[0015] Furthermore, the groove has an S-shaped structure.

[0016] Furthermore, before laser metal additive and subtractive processing, the metal plate is first pickled or alkali-washed.

[0017] Specifically, in step S1, the surface of the metal plate is provided with phosphate or graphite.

[0018] Specifically, in step S1, the hole drilled in the center of the metal plate welding area is a stepped hole.

[0019] Specifically, in step S2, the thermoplastic composite material plate is placed on top of the metal plate, and then the thermoplastic composite material plate and the metal plate are fixed so that the holes on the thermoplastic composite material plate and the metal plate coincide. The rivet is placed between the welding head and the upper surface of the workpiece to be welded and is placed in the coincided hole. Then the ultrasonic welding head is started. After the vibration is completed, the workpiece is cooled under the action of welding pressure to complete the welding.

[0020] Furthermore, in the rivet area, ultrasonic vibration and welding pressure melt the composite rivet, which then undergoes self-fusion welding upon cooling. Outside the rivet area, the thermoplastic composite material plate and the metal plate experience interfacial friction under ultrasonic vibration, causing the interfacial resin to melt and flow into the grooves on the surface of the metal plate under welding pressure. After cooling, mechanical interlocking is achieved. Simultaneously, the spikes formed on the metal surface are inserted into the woven carbon fiber structure of the thermoplastic composite material plate, achieving mechanical anchoring upon cooling.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] This invention relates to an ultrasonic composite riveting method for continuous fiber reinforced thermoplastic composite materials and metals. The method utilizes a combination of continuous fiber reinforced thermoplastic composite materials and metals, both of which possess excellent mechanical properties, offering inherent advantages over short fiber reinforced or non-fiber reinforced composite material joining processes. During metal plate processing, surface laser metal additive and subtractive processing is employed, simultaneously creating grooves and spikes in a single operation. This results in high processing efficiency, cost savings, and combines the advantages of ultrasonic welding and self-fusion riveting. The method is highly efficient, fast, low-cost, produces high-strength and high-quality joints, and facilitates automated production and control. Compared to individual joining processes, it exhibits superior tensile, shear, peel, and torsional resistance.

[0023] Furthermore, during the piercing process of the thermoplastic composite board, the overall heating and needle piercing technology is adopted. The braided fibers are separated during the piercing process, which reduces the damage to the fiber structure in the thermoplastic composite board and minimizes the impact of ultrasonic composite riveting on the performance of the fiber-reinforced thermoplastic composite board itself.

[0024] Furthermore, the matrix is ​​a thermoplastic polymer material that can be repeatedly heated and melted, and can flow after softening at high temperatures. The volume fraction of carbon fiber is 20% to 60%, including but not limited to polymers such as polyethylene, polyetheretherketone, polyphenylene sulfide, and polyethylene terephthalate. This is to meet the requirement that the matrix can melt and fuse during ultrasonic welding. At the same time, the fiber-reinforced composite material plates made from these matrices have excellent physical properties, such as good corrosion resistance and aging resistance.

[0025] Furthermore, a surface laser metal additive and subtractive processing method is adopted when treating the metal surface. Through program design, grooves are processed on the surface of the metal plate using a laser beam without powder spreading. Then, with powder spreading, spikes are printed on the metal plate. Grooves and spikes are processed simultaneously in one process, which is highly efficient and saves costs.

[0026] Furthermore, the grooves processed on the metal surface by the laser beam without powder spreading are arranged in an S-shape, which occupies more area than straight microgrooves and can adhere more resin during welding, aiming to increase mechanical interlocking.

[0027] Furthermore, acid or alkali washing can remove the surface oxide layer, making subsequent processing easier.

[0028] Furthermore, coatings such as phosphates and graphite are applied to the surface of the metal plate to improve its absorption rate of laser light, thereby reducing the difficulty of metal additive and subtractive processing.

[0029] Furthermore, when drilling, stepped holes are used to prevent rivets from loosening, taking into account that the metal plate is located in the lower position during the welding process.

[0030] Furthermore, the welding process employs a composite material plate on top and a metal plate below, which avoids direct contact between the ultrasonic welding head and the metal plate during vibration, protecting the welding equipment and extending the machine's lifespan. During fixing, aligning the holes in the thermoplastic composite plate and the metal plate helps with rivet positioning and prevents excessive vibration from causing the rivets to dislodge. After vibration, the workpiece needs to cool under welding pressure. This allows the molten rivet / thermoplastic composite matrix to completely fill the overlapping holes / grooves on the metal surface, facilitating better insertion of the metal surface's sharp protrusions into the woven fibers, resulting in a better welding effect.

[0031] Furthermore, in the rivet engagement area, self-fusion riveting is achieved by melting and re-solidifying the rivet. In the non-rivet engagement area, the thermoplastic composite matrix is ​​melted, and the resin melting and re-solidification achieve mechanical locking. The insertion of the spike protrusions into the braided fibers achieves mechanical anchoring. This combines the advantages of ultrasonic welding and self-fusion riveting, and compared with the individual connection processes, it has better tensile shear resistance, peel resistance, and torsional resistance.

[0032] In summary, the method of the present invention has better tensile, shear, peel, and torsional resistance, significantly improves the welding quality of composite materials and dissimilar metal materials, and is characterized by high efficiency, speed, and low cost. It solves the problem of the lack of a widely applicable joining technology in the field of metal-fiber reinforced thermoplastic composite material joining.

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall process of the present invention;

[0035] Figure 2 This is a schematic diagram of laser metal additive and subtractive processing on the surface of a metal plate.

[0036] Figure 3 This is a schematic diagram of the thermal puncture treatment for composite material plates;

[0037] Figure 4 This is a schematic diagram of the self-fusion riveting, mechanical interlocking, and mechanical anchoring formed during ultrasonic riveting.

[0038] Figure 5 This is a schematic diagram showing the morphology of the aluminum plate and the thermoplastic composite plate after pretreatment and the completed connection.

[0039] Among them: 21. Groove; 22. Spiked protrusion; 23. Stepped hole; 31. Hot piercing punch; 32. Needle; 33. Clamping bolt; 34. Upper clamp; 35. Thermoplastic composite material plate; 36. Anvil; 37. Environmental chamber; 41. Self-melting riveting; 42. Mechanical anchoring; 43. Mechanical interlock. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0042] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0043] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0044] Unless otherwise specified, the components or preferred components involved in this invention can be combined with each other to form new technical solutions.

[0045] In this invention, unless otherwise specified, the numerical range "a~b" represents an abbreviation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "6~22" means that all real numbers between "6~22" have been listed in this document, and "6~22" is simply an abbreviation of these numerical combinations.

[0046] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0047] In this invention, the term "and / or" as used herein refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0048] In this invention, unless otherwise stated, the various reactions or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0049] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0050] This invention provides an ultrasonic composite riveting method for continuous fiber-reinforced thermoplastic composite materials and metals. For the metal plate, surface laser additive / subtractive processing is used to form grooves and spikes on the metal surface, resulting in high processing efficiency. For the thermoplastic composite plate, thermal piercing technology is employed, minimizing the impact on the woven fibers. The two plates are joined through ultrasonic composite riveting, combining the advantages of ultrasonic welding and self-fusion riveting. This method exhibits superior comprehensive properties such as tensile and shear resistance, peel resistance, and torsional resistance, significantly improving the welding quality of dissimilar materials like composites and metals. This process is efficient, rapid, and low-cost, solving the problem of the lack of a widely applicable joining technology in the field of metal-fiber reinforced thermoplastic composite material joining.

[0051] Please see Figure 1 This invention discloses an ultrasonic composite riveting method for continuous fiber reinforced thermoplastic composite materials and metals, comprising the following steps:

[0052] S1. Before ultrasonic riveting, the metal plate is surface treated and drilled to form a central circular hole, surface spikes 22 and grooves 21 on the metal plate; the thermoplastic composite material plate 35 is surface cleaned and hot-punctured to remove oil stains from the plate surface and form a central circular hole.

[0053] S101, thermoplastic composite plate undergoes hot puncture;

[0054] Please see Figure 3 The surface cleaning and thermal puncture 11 of the thermoplastic composite plate 35 are specifically as follows:

[0055] Clean the thermoplastic composite material board 35 with alcohol, air dry it, and then place it in a temperature-controlled chamber with a stable temperature of 130-150°C for puncture using a puncture machine.

[0056] The matrix of the thermoplastic composite plate 35 is a thermoplastic polymer material that can be repeatedly heated and melted, and can flow after softening at high temperature. It includes, but is not limited to, polymers such as polyethylene, polyether ether ketone, polyphenylene sulfide, and polyethylene terephthalate. This is to meet the requirement that the matrix can melt and fuse during ultrasonic welding. The reinforcing fiber is high-performance carbon fiber, which is used to enhance the physical properties of the composite plate and improve its corrosion resistance, aging resistance, etc.

[0057] The purpose of cleaning with alcohol is to remove oil stains from the surface of the board.

[0058] Inside the environmental chamber 37, a thermoplastic composite material plate 35 is placed on an anvil 36. Upper clamps 34 are respectively provided at both ends of the upper side of the thermoplastic composite material plate 35. The two ends of the upper clamps 34 are fastened together by clamping bolts 33. A hot piercing punch 31 is set above the thermoplastic composite material plate 35. The piercing mold of the hot piercing punch 31 is a needle 32 with a diameter of 3mm. Due to the piercing effect, the formed through hole forms a funnel-shaped depression on the thermoplastic composite material plate 35 away from the welding interface. Compared with the traditional mechanical processing method of opening holes, this piercing method heats and softens the resin matrix material. The piercing is carried out by using a specially designed piercing device and clamping device. During the piercing process, the braided fibers are separated to minimize damage to the carbon fiber.

[0059] S102, Additive and Subtractive Material Treatment of Metal Plate Surface

[0060] The specific steps for surface treatment and drilling of the metal plate are as follows:

[0061] The contact surface between the metal plate and the thermoplastic composite plate 35 is pickled or alkali-washed, and then the surface of the contact surface is subjected to surface laser metal addition and subtraction processing 12. Finally, a hole is drilled in the center of the welding area using a drilling machine.

[0062] Metal plates are metals with high laser absorption efficiency, such as stainless steel and aluminum. At the same time, coating materials such as phosphate and graphite can be applied to the surface of the metal plate to improve its laser absorption rate, thereby reducing the difficulty of metal additive and subtractive processing.

[0063] The purpose of pickling or alkaline washing is to remove the surface oxide layer, making subsequent processing easier.

[0064] Please see Figure 2 The specific process of laser metal addition and subtraction processing on the surface of a metal plate is as follows:

[0065] The sequence of laser etching and selective laser additive manufacturing in a metal 3D printer is controlled. An "S-shaped" groove 21 is processed on the metal surface using a laser beam without powder spreading. Then, with powder spreading, a metal laser 3D printing process is used to form spikes 22 on the metal plate, aiming to achieve anchoring in the composite material by utilizing the convex shape of the pin.

[0066] When drilling, considering that the metal plate is located at the bottom during the welding process, a stepped hole 23 is adopted to prevent the rivets from loosening.

[0067] S2. The thermoplastic composite material plate obtained in step S1 is ultrasonically composite welded to the metal plate, and mechanical interlocking is achieved by resin melting.

[0068] The thermoplastic composite material plate 35 obtained in step S1 is placed on top of the metal plate. Then, the thermoplastic composite material plate 35 and the metal plate are fixed on the welding table of the ultrasonic welding machine, so that the holes on the thermoplastic composite material plate 35 and the metal plate coincide. The rivet is placed between the welding head and the upper surface of the workpiece to be welded and is placed in the coincided hole. The self-fusion welding 41 of the composite material rivet is achieved by ultrasonic vibration and welding pressure.

[0069] Please see Figure 4 and Figure 5 During the welding process, in the riveting area, high-frequency ultrasonic vibration and welding pressure are applied to the composite material rivet, causing its temperature to rise and melt. Under the action of welding pressure, the rivet completely fills the holes between the composite material plate and the metal plate, realizing the self-fusion welding of the composite material rivet 41.

[0070] In the non-welding area, the thermoplastic composite material plate 35 and the metal plate undergo interfacial friction under the action of ultrasonic vibration, the local temperature rises, the interfacial resin melts, and flows into the groove 21 on the surface of the metal plate under the action of welding pressure, realizing mechanical interlocking 43; at the same time, the spike protrusions 22 formed on the metal surface are inserted into the woven carbon fiber structure of the thermoplastic composite material plate 35, realizing mechanical anchoring 42.

[0071] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0072] In both Embodiment 1 and Embodiment 2 of the present invention, a continuous carbon fiber reinforced polycarbonate composite plate with a length of 101.6 mm, a width of 25.4 mm, and a thickness of 2 mm is used, wherein the volume fraction of carbon fiber is 40%; the metal plate material used in Embodiment 1 is 7Cr17, and the metal plate material used in Embodiment 2 is Al6061.

[0073] Example 1

[0074] This invention discloses an ultrasonic composite riveting process for continuous fiber-reinforced thermoplastic composite materials and metals:

[0075] The metal selected in this embodiment is

[0076] Before ultrasonic riveting, the stainless steel plate undergoes surface treatment and drilling. The side that will contact the thermoplastic composite plate is acid-washed or alkali-washed to remove the surface oxide layer, making subsequent processing easier. After surface treatment, the stainless steel plate is fixed in a UN250M model SLM selective laser sintering 3D printer, which is based on selective laser melting and uses a high-density laser to melt and bond metal powder together. Through programming design, the surface of the stainless steel plate is first laser-etched using a laser beam without powder spread, forming a shape such as... Figure 2 The S-shaped microgrooves shown are then 3D printed using a laser beam on the surface of a stainless steel plate, with powder spread, to form a shape resembling... Figure 2 The spiked protrusions are shown. Then, a drill press is used to drill holes in the stainless steel plate to obtain... Figure 2 The stepped hole shown.

[0077] Clean the composite material board with alcohol, allow it to air dry completely, and then fix it to... Figure 3 On the base of the environmental chamber shown, the temperature of the temperature control chamber needs to be stabilized at 130-150℃. At this temperature, the composite material substrate softens due to heat. The piercing die of the piercing machine is a long needle with a diameter of 3mm. Under the action of piercing pressure, the hot piercing needle pierces into the composite material plate, and during the piercing process, it separates the braided fibers to form a funnel-shaped through hole.

[0078] The composite material plate and stainless steel plate obtained from the first two steps are fixed on the welding table in an upward and downward order, ensuring that the holes formed during the pretreatment coincide. Short fiber reinforced thermoplastic composite rivets are placed in these coinciding holes. In the riveting area, self-fusion riveting of the composite rivets is achieved through ultrasonic vibration and welding pressure. During welding, in the riveting area, high-frequency ultrasonic vibration and high welding pressure act on the composite rivets, causing them to heat up and melt. Under the welding pressure, they completely fill the holes in the composite material plate and stainless steel plate, achieving self-fusion riveting. In the non-welding area, the composite material plate and stainless steel plate experience interfacial friction under ultrasonic vibration, resulting in a localized temperature increase and melting of the interfacial resin. Under the welding pressure, this resin flows into the grooves on the surface of the stainless steel plate, achieving mechanical interlocking. Simultaneously, the spikes formed on the stainless steel surface insert into the woven carbon fiber structure of the composite material plate, achieving an anchoring effect.

[0079] Example 2

[0080] This invention discloses an ultrasonic composite riveting process for continuous fiber-reinforced thermoplastic composite materials and metals:

[0081] The metal selected in this embodiment is Al6061. Compared with stainless steel, Al6061 has a lower utilization rate of laser energy, and the power of the laser generator needs to be increased during the laser additive and subtractive processing of metal surfaces.

[0082] Before ultrasonic riveting, the aluminum plate undergoes surface treatment and drilling. The side that will contact the thermoplastic composite plate is acid-washed or alkali-washed to remove the surface oxide layer, making subsequent processing easier. After surface treatment, the aluminum plate is fixed in a UN250M model SLM selective laser sintering 3D printer, which is based on selective laser melting and uses a high-density laser to melt and bond metal powder together. Through programming design, the surface of the aluminum plate is first laser-etched using a laser beam without powder spreading, forming a shape such as... Figure 2 The S-shaped microgrooves shown are then 3D printed using a laser beam on the aluminum plate surface under powder-spread conditions, forming a shape as shown. Figure 2 The pointed protrusions are shown. Then, a drill press is used to drill holes in the aluminum plate to obtain... Figure 5 The countersunk hole shown.

[0083] Clean the composite material board with alcohol, allow it to air dry completely, and then fix it to... Figure 3 On the base of the environmental chamber shown, the temperature of the temperature control chamber needs to be stabilized at 130-150℃. At this temperature, the composite material substrate softens due to heat. The puncture machine uses a 3mm diameter long needle as its puncture die. Under puncture pressure, the heated puncture needle penetrates the composite material board, separating the woven fibers during the puncture process to form... Figure 5The funnel-shaped through-hole is shown.

[0084] The composite material plate and metal plate obtained from the first two steps are fixed on the welding table in an upward and downward order, ensuring that the holes formed during the pretreatment coincide. Short fiber reinforced thermoplastic composite rivets are placed in these coinciding holes. In the riveting area, self-fusion riveting of the composite material rivets is achieved through ultrasonic vibration and welding pressure. During welding, in the riveting area, high-frequency ultrasonic vibration and high welding pressure act on the composite material rivets, causing them to heat up and melt. Under the welding pressure, they completely fill the holes in the composite material plate and metal plate, achieving self-fusion riveting. In the non-welding area, the composite material plate and metal plate experience interfacial friction under ultrasonic vibration, resulting in a localized temperature increase and melting of the interfacial resin. Under the welding pressure, this resin flows into the grooves on the surface of the metal plate, achieving mechanical interlocking. Simultaneously, the spikes formed on the metal surface insert into the woven carbon fiber structure of the composite material plate, achieving an anchoring effect.

[0085] In summary, this invention provides an ultrasonic composite riveting method for continuous fiber reinforced thermoplastic composite materials and metals. The method involves pre-treating both the composite material plate and the metal plate separately, forming unique structures on each type of plate, and finally connecting the two plates using ultrasonic composite riveting. This invention proposes two different material combinations and pre-treatment methods to achieve the connection between continuous fiber reinforced thermoplastic composite material plates and metal plates. It offers advantages such as high efficiency, energy saving, speed, low cost, high strength and quality, excellent tensile and shear resistance, peel resistance, torsional resistance, aesthetically pleasing joints, and ease of automated production and control. It solves the problem of the lack of a widely applicable connection technology in the field of metal-fiber reinforced thermoplastic composite material joining.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultrasonic composite riveting method for continuous fiber reinforced thermoplastic composite materials and metals, characterized in that, Includes the following steps: S1. Perform hot piercing treatment on the thermoplastic composite sheet, perform surface laser metal addition and subtraction processing on the metal sheet, and then drill a hole in the center of the welding area of ​​the metal sheet. The specific laser metal addition and subtraction processing is as follows: Without powder coating, a laser beam is used to process an S-shaped groove on the surface of a metal plate; then, with powder coating, spikes are printed on the metal plate. The specific steps for hot puncture of thermoplastic composite plates are as follows: The thermoplastic composite board is cleaned with alcohol, air-dried, and then placed in a temperature-controlled chamber at 130~150℃ for puncture. The matrix of the thermoplastic composite board includes polyethylene, polyetheretherketone, polyphenylene sulfide, and polyethylene terephthalate. S2. The thermoplastic composite material plate obtained in step S1 is ultrasonically composite-welded to the metal plate. The composite welding is achieved through resin melting, spiked protrusions, and composite material rivets. Specifically, the thermoplastic composite material plate is placed on top of the metal plate, and then the thermoplastic composite material plate and the metal plate are fixed so that the holes on the thermoplastic composite material plate and the metal plate coincide. The rivet is placed between the welding head and the upper surface of the workpiece to be welded and is placed in the coincided hole. Then the ultrasonic welding head is started. After vibration, the workpiece cools under the action of welding pressure to complete the welding. In the rivet area, ultrasonic vibration and welding pressure melt the composite material rivet, and after cooling, self-fusion riveting is completed. Outside the rivet area, the thermoplastic composite material plate and the metal plate undergo interfacial friction under the action of ultrasonic vibration. The interfacial resin melts and flows into the S-shaped groove on the surface of the metal plate under the action of welding pressure. After cooling, mechanical interlocking is achieved. At the same time, the spiked protrusions formed on the metal surface are inserted into the woven carbon fiber structure of the thermoplastic composite material plate and mechanical anchoring is achieved after cooling.

2. The ultrasonic composite riveting method for continuous fiber reinforced thermoplastic composite material and metal according to claim 1, characterized in that, Before laser metal addition and subtraction processing, the metal plate is first pickled or alkali-washed.

3. The ultrasonic composite riveting method for continuous fiber reinforced thermoplastic composite material and metal according to claim 1, characterized in that, In step S1, the surface of the metal plate is provided with phosphate or graphite.

4. The ultrasonic composite riveting method for continuous fiber reinforced thermoplastic composite material and metal according to claim 1, characterized in that, In step S1, the center hole of the metal plate welding area is a stepped hole.

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