A device and method for dismounting a local bonded patch of a thin-walled carbon fiber composite material

Abstract

The application provides a device and method for dismounting local bonding patch of thin-walled carbon fiber composite material, which comprises a laser impact module, a workpiece clamping module and an adaptive wave absorber. The laser impact module applies pulsed laser to the patch area to induce unloading wave to weaken the bonding strength. The adaptive wave absorber is composed of a plurality of pin units sharing one equal pressure cavity to form a pneumatic driving array, each unit having a retractable pin push rod and a flexible wave absorbing head. By applying air pressure to the equal pressure cavity, all wave absorbing heads are synchronously extended and adaptively attached to the back of the workpiece. The wave absorbing head is made of flexible material with acoustic impedance matched with carbon fiber composite material, which transmits and dissipates the shock wave energy through the substrate, avoiding damage from back reflection. The application realizes non-destructive and non-contact dismounting of the patch, is suitable for complex curved surfaces, and is simple, convenient and efficient to operate.

Description

Technical Field

[0001] This invention relates to the field of CFRP material repair, and in particular to an apparatus and method for disassembling locally bonded patches of thin-walled carbon fiber composite materials. Background Technology

[0002] Carbon fiber reinforced polymer (CFRP) composites, due to their high specific strength, high specific modulus, good fatigue resistance, and excellent corrosion resistance, have been widely used in thin-walled structural components in aerospace, rail transportation, shipbuilding, and high-end equipment industries. For example, CFRP materials are gradually replacing traditional metal materials as the mainstream choice in key components such as aircraft wing skins, fuselage panels, satellite antenna reflectors, and rocket fuel tanks. However, CFRP components inevitably encounter various localized damages during long-term service, such as delamination and microcracks caused by low-velocity impacts, and holes caused by foreign object penetration.

[0003] For the aforementioned localized damage, the most commonly used repair method in engineering is the adhesive patch method. This method involves bonding a pre-cured patch to the damaged area using a high-performance structural adhesive, followed by curing under heat and pressure to restore the structure's load-bearing capacity. Compared to bolted connections or mechanical fastening repairs, the adhesive patch method offers significant advantages such as uniform stress distribution, no stress concentration, preservation of original fiber continuity, and good aerodynamic shape maintenance. However, when the patch itself suffers secondary damage (e.g., aging and cracking), the repair quality is substandard requiring rework, or the original structure needs to be re-maintained, efficiently and non-destructively removing the firmly bonded patch from the thin-walled substrate becomes a major technical challenge in the field of composite material repair.

[0004] Currently, traditional methods for removing patches mainly include three types: mechanical peeling, chemical solvent peeling, and thermal peeling. Mechanical peeling uses tools such as scrapers and pry bars to forcibly insert into the adhesive layer from the patch edge and apply prying force to separate the patch from the substrate. This method is simple to operate, but it easily generates new microcracks, fiber fuzzing, or even large-area delamination on thin-walled CFRP substrates, especially when the substrate thickness is less than 2mm, where the secondary damage caused by mechanical force is often devastating. Chemical solvent peeling utilizes organic solvents (such as acetone and dichloromethane) that can dissolve or swell the adhesive to penetrate into the adhesive layer, thereby reducing the bond strength. Although this method causes less mechanical damage to the substrate, the penetration period is usually several hours or even days, making it inefficient; at the same time, organic solvents may corrode the CFRP matrix resin, leading to a decrease in the mechanical properties of the substrate itself. Thermal peeling uses heat sources such as hot air guns and infrared heaters to locally heat the patch area. When the adhesive layer temperature exceeds its glass transition temperature or thermal decomposition temperature, the adhesive softens or carbonizes, significantly reducing the bond strength. However, the thermal stability of CFRP matrix resin is usually comparable to or even lower than that of adhesives. Local high temperatures can easily cause the base resin to soften, carbonize, or even burn, resulting in irreversible damage.

[0005] In recent years, laser shockwave technology has been increasingly adopted in the field of interfacial debonding due to its high energy density, ultrafast action time, and non-contact operation. The basic principle of this technology is that a high-energy pulsed laser irradiates the absorber layer through a confinement layer, causing the absorber layer material to vaporize and ionize instantaneously, forming plasma. Under the confinement of the confinement layer, the plasma generates a high-pressure shockwave. After propagating to the adhesive layer interface, the elastic recovery of the material forms an unloading wave, and the tensile stress generated by the unloading wave causes the adhesive layer to peel off. However, directly applying laser shockwave technology to the disassembly of thin-walled CFRP patches faces significant technical challenges. When the compressive component of the shockwave passes through the patch, adhesive layer, and CFRP substrate, and reaches the free back side of the substrate, the acoustic impedance changes abruptly (the acoustic impedance of the air on the back side is much smaller than that of the solid material), causing the compressive wave to reflect and transform into a tensile wave. This reflected tensile wave, propagating within the CFRP, easily causes delamination damage at the weakest point of interlayer bonding (i.e., between the fiber layer and the resin layer). Since the thickness of thin-walled CFRP structures is usually only 1~3mm, the reflected waves return to the adhesive layer area in a very short time. Often, before the patch is completely detached, the substrate has already shown invisible internal delamination or visible fiber peeling, resulting in the scrapping of the entire repair.

[0006] Therefore, how to efficiently remove patches using laser shock waves while effectively eliminating or reducing damage caused by reflected waves from the back of the substrate is a pressing technical problem in this field. In other words, there is a need for a device and method that can both utilize laser-induced unloading waves to achieve patch debonding and protect the thin-walled CFRP substrate from damage caused by reflected waves. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an apparatus and method for disassembling locally bonded patches of thin-walled carbon fiber composite materials. It utilizes a high-energy nanosecond pulsed laser to induce a shock wave, creating an unloading wave that damages the interlayer interfaces of the material. By planning the impact area and the laser spot's path, the bonding strength of the CFRP material in the repair area is weakened. Furthermore, the apparatus uses a material with acoustic impedance similar to CFRP as a backing absorber to reduce the reflection of the laser-induced shock wave on the free surface, preventing damage to the CFRP interface under the shock wave.

[0008] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0009] A device for disassembling locally bonded patches of thin-walled carbon fiber composite materials includes a laser shock module, a workpiece clamping module, and an adaptive wave absorber.

[0010] The workpiece clamping module is used to clamp the workpiece to be repaired.

[0011] The laser shock module is used to apply pulsed laser to the patch removal area of ​​the part to be repaired, inducing shock waves to weaken the adhesive strength between the patch and the substrate.

[0012] The adaptive absorber is located on the back side of the part to be repaired and is used to absorb the shock wave energy passing through the substrate during laser shock to reduce back reflection.

[0013] The adaptive absorber is a pneumatically driven array consisting of multiple pin units. Each pin unit includes an axially extendable pin push rod and an absorber head fixed to the end of the pin push rod. All pin units share a pressure equalization chamber. By applying air pressure to the pressure equalization chamber, all pin push rods are driven to extend synchronously, so that each absorber head adaptively fits the corresponding position on the back of the part to be repaired. The absorber head is used to transmit and dissipate the shock wave energy passing through the substrate.

[0014] Furthermore, each pin unit also includes a return spring, a unit cavity, and a piston; the return spring is sleeved on the pin push rod and is used to automatically retract the pin push rod after the pressure equalization chamber is depressurized; the piston is installed in the unit cavity, and one end of the pin push rod is connected to the piston; the unit cavity is provided with a pressure equalization chamber, and the pressure equalization chambers of all pin units are interconnected.

[0015] Furthermore, the adaptive absorber also includes a pressure regulating valve and a pressure sensor connected to the isobaric chamber. The pressure sensor provides feedback to regulate the air pressure in the isobaric chamber, so that the contact pressure between the absorber head and the back of the part to be repaired is maintained within the range of 0.1MPa to 0.5MPa, avoiding air gap residue and reducing sound transmission efficiency.

[0016] Furthermore, the absorber head is made of a composite material with polyurethane elastomer as the matrix and tungsten powder added, and the acoustic impedance of the composite material is matched with that of the carbon fiber composite material.

[0017] Furthermore, the area of ​​the mating surface formed by all the absorbing heads in the adaptive absorber is at least 1.5 times the area of ​​the laser shock scanning area.

[0018] Furthermore, the pulsed laser applied by the laser shock module is a nanosecond pulsed laser beam with a wavelength of 1064nm or 532nm, a pulse width of 10ns~20ns, a pulse energy of 5J~10J, and a laser spot diameter of not less than 3mm.

[0019] Furthermore, it also includes a machine vision module and a computer control module.

[0020] The machine vision module is used to acquire images of the debonding state of the patch edge of the part to be repaired in real time; the computer control module is connected to the laser shock module, the machine vision module and the adaptive absorber respectively, to coordinate the work of each module.

[0021] A method for disassembling a partially bonded patch of thin-walled carbon fiber composite material, comprising the following steps:

[0022] The workpiece to be repaired is fixed by the workpiece clamping module, so that the patch removal area is facing the laser impact module.

[0023] Apply air pressure into the equal pressure chamber to drive all pin push rods to extend synchronously, so that each absorber head adaptively fits into the position corresponding to the back of the part to be repaired and the patch removal area.

[0024] A pulsed laser is applied to the patch removal area to induce a shock wave that weakens the adhesive strength between the patch and the substrate. At the same time, the energy of the shock wave that passes through the substrate is transmitted and dissipated by the absorber.

[0025] Continue until the edge of the patch is significantly raised or the adhesive layer cracks through, then release the pressure in the equal pressure chamber, causing the pin push rod to retract and remove the detached patch.

[0026] Furthermore, before applying pulsed laser to the patch removal area, a continuous water curtain with a thickness of 2mm to 3mm is first formed on the patch surface as a constraint layer.

[0027] The beneficial effects of this invention are as follows:

[0028] 1. The apparatus and method for disassembling locally bonded patches of thin-walled carbon fiber composite materials, as described in this invention, utilizes an adaptive absorber on the back of the component to be repaired. A flexible absorber material (a composite material with a polyurethane elastomer matrix and tungsten powder added) with acoustic impedance matching the CFRP substrate is employed. This ensures that when the shock wave energy passing through the substrate reaches the back of the substrate, due to the minimal difference in acoustic impedance between the absorber and the substrate, most of the energy is transmitted into the absorber and absorbed by its internal viscoelastic dissipation mechanism, preventing strong reflection on the back side. This combination of acoustic impedance matching and energy absorption effectively avoids the CFRP interlayer delamination and fiber peeling damage caused by reflected tensile waves in traditional laser shock peening processes, achieving complete debonding of the patch while maintaining the integrity of the substrate structure.

[0029] 2. The device and method for disassembling locally bonded patches of thin-walled carbon fiber composite materials according to the present invention employs a pneumatically driven multi-pin array design for the adaptive absorber. All pin units share a single isobaric chamber, and applying air pressure into the isobaric chamber drives all pins to extend synchronously. Due to the isotropic transmission characteristics of fluid pressure within the closed chamber, each pin push rod can automatically adjust its extension length according to the actual shape of the back of the workpiece to be repaired (including curved surfaces, wrinkles, steps, or irregular concavities and convexities), ensuring that each flexible absorber head adheres to the workpiece surface with appropriate pressure. This eliminates the need for custom-made absorber pads for different workpiece shapes, ensuring a continuous, gapless acoustic transmission interface between the absorber head and the back of the workpiece under various complex curved surface conditions, thereby achieving a stable and reliable absorption effect.

[0030] 3. The device and method for disassembling locally bonded patches of thin-walled carbon fiber composite materials according to the present invention also integrate a machine vision module and a computer control module. A CCD camera acquires images of the patch edge in real time, and the computer analyzes the images to determine the debonding progress (such as edge lifting height and whether adhesive layer cracks penetrate), and decides whether repeated laser impact is necessary. This real-time monitoring and closed-loop control method avoids incomplete debonding due to insufficient impact cycles, and also avoids unnecessary energy waste or cumulative impact on the substrate due to excessive impact cycles, thus achieving precise control. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For those skilled in the art, it is obvious that other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1This is a schematic diagram of the device for disassembling locally bonded patches of thin-walled carbon fiber composite materials according to the present invention.

[0033] Figure 2 This is a schematic diagram of the laser-induced shock wave disassembly process described in this invention.

[0034] Figure 3 This is a schematic diagram of the laser scanning path and spot coverage described in this invention.

[0035] Figure 4 This is a diagram showing the relative positional relationship between the visual judgment device and the repair area described in this invention.

[0036] Figure 5 This is a schematic diagram of the adaptive absorber described in this invention.

[0037] Figure 6 This is a structural diagram of the pin unit described in this invention.

[0038] In the picture:

[0039] 1-Part to be repaired; 101-Patch removal area; 102-Laser scanning path; 103-Laser spot; 2-Robot arm; 3-Computer; 4-Laser; 5-Laser beam; 6-Reflector; 7-Adaptive absorber; 701-Absorber head; 702-Reset spring; 703-Pin push rod; 704-Gasket; 705-Unit cavity; 706-Air outlet; 707-Piston; 710-Fixing nut; 711-Isobaric chamber; 8-Clamping platform; 9-Controller; 10-Supply light; 11-CCD camera; 12-Miniature water pump; 13-Nozzle; 14-Water supply tank; 15-Water pipe; 16-Laser head. Detailed Implementation

[0040] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0041] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] like Figure 1 As shown, the device for disassembling locally bonded patches of thin-walled carbon fiber reinforced polymer (CFRP) composite materials according to the present invention includes a laser shock module, a workpiece clamping module, and an adaptive wave absorber 7.

[0044] The laser shock module is used to apply pulsed laser light to the patch removal area 101 of the part to be repaired 1, inducing a shock wave to weaken the adhesive strength between the patch and the substrate. The laser shock module includes a nanosecond pulsed laser 4, several reflectors 6 for changing the optical path, an adjustable laser head 16, and a water supply unit for forming a constraint layer. The water supply unit includes a water tank 14, a micro water pump 12, a water pipe 15, and a nozzle 13. The micro water pump 12 is located inside the water tank 14 and is connected to the nozzle 13 through the water pipe 15. During operation, the micro water pump 12 draws deionized water from the water tank 14 and delivers it to the nozzle 13 through the water pipe 15. The nozzle 13 sprays water evenly onto the surface of the patch to be removed, forming a continuous water curtain with a thickness of about 2-3 mm. The water curtain has a dual function: on the one hand, it constrains the laser-induced plasma expansion and enhances the shock wave pressure; on the other hand, it absorbs residual laser energy and prevents thermal damage. The parameters of the nanosecond pulsed laser 4 can be selected within a certain range according to actual needs. This embodiment employs a nanosecond pulsed laser with an output wavelength of 1064nm or 532nm, a pulse width of 10ns~20ns, a pulse energy of 5J~10J, and a laser spot diameter of not less than 3mm. These parameters ensure sufficient impact pressure while avoiding thermal damage or excessive mechanical impact to the thin-walled CFRP substrate.

[0045] The workpiece clamping module is used to fix the part to be repaired 1 in a predetermined position, ensuring that the laser beam can be incident on the patch removal area 101 at a suitable angle (usually vertical) and can continuously scan the entire patch area according to the planned path. The workpiece clamping module can use conventional mechanical clamps or vacuum suction cups, the specific form depending on the shape and size of the workpiece, as long as it does not interfere with the operation of other modules. In this embodiment, the part to be repaired 1 is gripped by the robotic arm 2 and fixed on the clamping platform 8.

[0046] The adaptive absorber 7 is disposed on the back side of the component 1 to be repaired, and is used to absorb the shock wave energy passing through the substrate during laser shock to reduce back-side reflection; Figure 5 and Figure 6As shown, the adaptive absorber 7 is a pneumatically driven array composed of multiple pin units. Each pin unit includes an axially extendable pin push rod 703, an absorber head 701 fixed to the end of the pin push rod, a return spring 702, a unit cavity 705, and a piston 707. The piston 707 is installed inside the unit cavity 705, and one end of the pin push rod 703 is connected to the piston 707. The return spring 702 is sleeved on the pin push rod 703 and is used to automatically retract the pin push rod 703 after the pressure in the equal pressure chamber 711 is depressurized. The unit cavity 705 is provided with an equal pressure chamber 711, and the equal pressure chambers 711 of all pin units are interconnected to form a common pressure space. By applying air pressure into the equal pressure chamber 711, utilizing the isotropic transmission characteristics of fluid pressure, all pin push rods 703 are driven to extend outward synchronously, so that each absorber head 701 adaptively fits the corresponding position on the back of the part 1 to be repaired. Because each pin unit moves independently, even if the back of the part to be repaired 1 has a curved surface, wrinkles or local unevenness, each absorber head 701 can adjust its extension length individually, ultimately achieving good conformal fit.

[0047] The adaptive absorber 7 also includes a pressure regulating valve and a pressure sensor connected to the isobaric chamber 711. The pressure sensor provides feedback to regulate the air pressure in the isobaric chamber, so that the contact pressure between the absorber head 701 and the back of the workpiece 1 to be repaired is maintained within the range of 0.1MPa to 0.5MPa. This ensures that there is no air gap between the absorber head and the substrate, and also prevents additional compression damage to the thin-walled CFRP.

[0048] The absorber head 701 is used to transmit and dissipate the energy of shock waves passing through the substrate. In this embodiment, the absorber head 701 is made of a composite material with polyurethane elastomer as the matrix and tungsten powder added. In this embodiment, by adding 75% by mass of tungsten powder, the acoustic impedance of the absorber head 701 is adjusted to 4.5 M ayls to match the acoustic impedance of CFRP, which can effectively reduce shock wave reflection; Figure 2 As shown, when the compression component of the shock wave passing through the substrate reaches the back side of the substrate, due to the extremely small difference in acoustic impedance between the absorber head 701 and the substrate, most of the shock wave energy will be transmitted into the absorber head 701 and absorbed by its internal viscoelastic dissipation mechanism, without strong reflection on the back side. This avoids the risk of CFRP layer delamination caused by tensile stress from reflected waves in traditional laser shock absorbing processes. Furthermore, to ensure effective coverage of the back side of the entire patch removal area, the area of ​​the mating surface formed by all the absorbers 701 in the adaptive absorber 7 should be at least 1.5 times the area of ​​the laser shock scanning area, thus providing sufficient absorption protection even at the edges.

[0049] To achieve automated closed-loop control, the present invention may further include a machine vision module and a computer 3. The machine vision module includes a supplementary light 10 and a CCD camera 11, used to acquire real-time images of the debonding state of the edge of the patch to be repaired 1. Figure 4 As shown, the CCD camera 11 can be installed near the end of the laser scanning path, with its optical axis coinciding as closely as possible with the extension direction of the laser scanning path's end. The fill light 10 and the optical axis of the CCD camera 11 form an angle of approximately 120° to create good edge illumination. The computer 3 is connected to the laser shock module, the machine vision module, and the adaptive absorber 7 to coordinate the operation of each module. The computer 3 receives the image from the CCD camera 11, uses an edge detection algorithm to determine whether the patch is warped or whether the adhesive layer crack is penetrating, and decides whether to continue with the next round of laser scanning based on this information.

[0050] The method for disassembling a partially bonded thin-walled carbon fiber composite patch according to the present invention includes the following steps:

[0051] Step S01: Surface pretreatment of the patch and workpiece clamping, as detailed below:

[0052] Lightly sand the entire surface of the patch to be removed using 400# sandpaper to remove surface contaminants and create micro-roughness, which will enhance laser energy absorption when applying black tape later. After sanding, wipe the surface with an alcohol swab to remove dust. After the alcohol evaporates, apply a layer of black tape to the patch surface. The purpose of the black tape is to increase the absorption rate of the patch surface for 1064nm wavelength laser, thus enabling stable plasma generation even at lower laser energies. Subsequently, place the patch to be repaired 1 with the tape applied onto the workpiece clamping module, adjust its position so that the patch removal area 101 is directly opposite the laser head 16, and lock the clamp.

[0053] Step S02: Activate the air pressure regulating valve connected to the equal pressure chamber 711 to slowly inject compressed air into the equal pressure chamber. Observe the pressure sensor reading and simultaneously check whether the absorber head 701 has contacted the back side of the workpiece 1 to be repaired. When the absorber head 701 just contacts the back side, continue to pressurize until it reaches between 0.1 and 0.5 MPa. Maintain this pressure for several seconds to allow the absorber head 701 to fully deform and squeeze out any air bubbles that may exist on the interface, achieving a conformal and seamless fit with the back side of the workpiece. For workpieces with particularly complex curved surfaces, the pressure can be appropriately increased to the upper limit of 0.5 MPa, but it should not be exceeded to avoid damaging the thin-walled substrate.

[0054] Step S03: Position the CCD camera 11 and the fill light 10 according to... Figure 4The CCD camera 11 should be positioned according to the indicated relationship. Specifically, the CCD camera 11 should be installed near the end of the laser scanning path, with its optical axis coinciding as closely as possible with the extension direction of the laser scanning path. The supplementary light 10 should be positioned to the side of the CCD camera 11, with an angle of approximately 120° between their optical axes. This creates a contrast between light and dark at the edge of the patch, facilitating observation of the warping height. Adjust the brightness and illumination angle of the supplementary light 10 so that the edge of the patch is clearly visible in the image captured by the CCD camera 11.

[0055] Step S04: Based on the actual dimensions of the patch to be removed (e.g., the diameter of a circular patch or the side length of a rectangular patch), input the scanning path into computer 3. For example... Figure 3 As shown, an S-shaped path is used to cover the entire patch area, with an overlap of approximately 10% to 20% between adjacent laser spots to ensure uniform impact. The outermost laser spot 103 should be tangent to the edge of the patch removal area 101, ensuring that the adhesive layer of the entire patch area is impacted while avoiding unnecessary surface damage to the substrate material outside the patch. The basic parameters of the laser are set as follows: wavelength of 1064nm or 532nm, pulse width of 10~20ns, pulse energy of 5~10J, and spot diameter of 3mm. The scanning speed is calculated based on the spot diameter and laser repetition frequency to ensure that each location receives approximately 1~2 impacts.

[0056] Step S05: Check if the water supply tank 14 has sufficient water and if the airtightness of each joint of the water supply pipe 15 is good. After confirming that everything is in order, start the micro water pump 12 and open the valve of the nozzle 13. Adjust the flow rate and spray angle of the nozzle 13 so that the water curtain evenly covers the entire area to be impacted, and the thickness of the water curtain is stable at 2~3mm.

[0057] Step S06: After checking that the optical surface of the reflector 6 is free from contamination or damage, the laser 4, CCD camera 11, and supplementary light 10 are activated sequentially. The scanning path and speed set in step S04 are loaded into the computer 2, and then a command to start the impact is issued. The laser 4 emits a pulsed laser beam 5 along the predetermined path, which is guided by the reflector 6 to the laser head 16 and finally passes through the water curtain and focuses on the black adhesive tape on the surface of the patch. Each pulse vaporizes and ionizes the surface material to form plasma within nanoseconds, generating a shock wave towards the interior of the patch under the constraint of the water curtain. During the propagation of the shock wave, the compression wave first reaches the patch / adhesive layer interface and then continues to propagate towards the substrate and the absorber head; then, due to the elastic recovery of the material, an unloading wave is formed on the patch / adhesive layer interface. This unloading wave manifests as tensile stress, which, under repeated action, gradually causes microcracks to form in the adhesive layer and propagate. At the same time, the compression wave passing through the substrate enters the acoustic impedance-matched flexible absorber head 701, where its energy is absorbed and dissipated, and it is no longer reflected back from the back of the substrate.

[0058] Step S07: The laser beam scans along the laser scanning path 102 once, and all the light spots 103 are covered in the predetermined positions, thus completing one layer of impact. At this time, the edge of the patch can be observed through the image captured by the CCD camera 11 to see if there are any tiny cracks or slight lifting. Usually, a single layer of impact is not enough to completely detach the patch, but local damage may have occurred inside the adhesive layer.

[0059] Step S08: Keeping all parameters unchanged, repeat the path scanning in step S07. After each layer of scanning is completed, computer 2 performs a rapid analysis of the image acquired by CCD camera 11 (or the operator observes it visually) to determine whether there is significant lifting at the edge of the patch and whether the adhesive layer crack penetrates the entire bonding surface. Once the debonding conditions are met (e.g., the edge of the patch lifts more than 0.5 mm and the crack is continuous), the impact is stopped immediately. In this embodiment, for a circular patch with a thickness of about 1 mm and a diameter of 20 mm, it is usually necessary to repeat the scanning 3 to 5 layers to achieve complete debonding.

[0060] Step S09: Turn off the laser 4, miniature water pump 12, nozzle 13, CCD camera 11, and fill light 10 in sequence. At this point, the adhesion between the patch and the substrate has been greatly reduced, and most areas have separated. Depending on the specific condition of the patch, it can be gently peeled off by hand, or a non-metallic tool such as a plastic scraper can be used to pry up the edges. Avoid using sharp metal tools to prevent scratching the substrate surface.

[0061] Step S10: A command is issued via computer 3 or controller 9 to release pressure from the air pressure regulating valve. The air pressure in the equal pressure chamber 711 decreases rapidly, the return spring 702 pushes the pin push rod 703 to retract, and the absorber head 701 automatically detaches from the back of the workpiece 1 to be repaired. After all pins have fully reset, the clamps of the workpiece clamping module are released, and the workpiece with the patch removed is taken off the clamping platform. This completes the entire patch removal process.

[0062] In practical applications, some parameters in the above methods can be adjusted within a certain range according to specific working conditions to achieve optimal disassembly efficiency and substrate protection. Acoustic impedance matching of the flexible absorber head 701 is crucial. After incorporating tungsten powder into the polyurethane matrix, the acoustic impedance can be adjusted within the range of approximately 2~8 MNayls. When adjusted to around 4.5 MNayls, it best matches the CFRP substrate. The contact pressure should be controlled between 0.1~0.5 MPa. Too low a pressure will result in air gap residue, reducing acoustic transmission efficiency; too high a pressure may damage the thin-walled structure. The laser spot diameter should not be less than 3 mm. A spot that is too small will result in excessively high peak pressure, easily damaging the substrate; a spot that is too large will reduce energy density and affect debonding efficiency. A water curtain thickness of 2~3 mm can effectively confine the plasma without causing excessive laser energy attenuation due to an excessively thick water layer.

[0063] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0064] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for disassembling partially bonded patches of thin-walled carbon fiber composite materials, characterized in that, Includes a laser shock module, a workpiece clamping module, and an adaptive wave absorber (7); The workpiece clamping module is used to clamp the workpiece to be repaired (1); The laser shock module is used to apply pulsed laser to the patch removal area (101) of the part to be repaired (1) to induce shock waves to weaken the adhesive strength between the patch and the substrate. The adaptive absorber (7) is disposed on the back side of the part to be repaired (1) to absorb the shock wave energy passing through the substrate during laser shock to reduce back reflection; The adaptive absorber (7) is a pneumatically driven array consisting of multiple pin units. Each pin unit includes a pin push rod (703) that can extend and retract along the axis and an absorber head (701) fixed to the end of the pin push rod. All pin units share a pressure equalization chamber (711). By applying air pressure to the pressure equalization chamber (711), all pin push rods (703) are driven to extend synchronously, so that each absorber head (701) adaptively fits to the corresponding position on the back of the part to be repaired (1). The absorber head (701) is used to transmit and dissipate the shock wave energy passing through the substrate.

2. The apparatus for disassembling locally bonded patches of thin-walled carbon fiber composite materials according to claim 1, characterized in that, Each pin unit also includes a return spring (702), a unit cavity (705), and a piston (707); the return spring (702) is sleeved on the pin push rod (703) and is used to automatically retract the pin push rod (703) after the pressure equalization chamber (711) is depressurized; the piston (707) is installed in the unit cavity (705), and one end of the pin push rod (703) is connected to the piston (707); the unit cavity (705) is provided with a pressure equalization chamber (711), and the pressure equalization chambers (711) of all pin units are interconnected.

3. The apparatus for disassembling partially bonded patches of thin-walled carbon fiber composite materials according to claim 2, characterized in that, The adaptive absorber (7) also includes a pressure regulating valve and a pressure sensor connected to the isobaric chamber (711). The pressure sensor provides feedback to regulate the pressure in the isobaric chamber, so that the contact pressure between the absorber head (701) and the back of the part to be repaired (1) is maintained in the range of 0.1MPa to 0.5MPa.

4. The apparatus for disassembling locally bonded patches of thin-walled carbon fiber composite materials according to claim 1, characterized in that, The absorber head (701) is made of a composite material with polyurethane elastomer as the matrix and tungsten powder added, and the acoustic impedance of the composite material is matched with that of the carbon fiber composite material.

5. The apparatus for disassembling partially bonded patches of thin-walled carbon fiber composite materials according to claim 1, characterized in that, The area of ​​the mating surface formed by all the absorbers (701) in the adaptive absorber (7) is at least 1.5 times the area of ​​the laser shock scanning area.

6. The apparatus for disassembling partially bonded patches of thin-walled carbon fiber composite materials according to claim 1, characterized in that, The pulsed laser applied by the laser shock module is a nanosecond pulsed laser beam with a wavelength of 1064nm or 532nm, a pulse width of 10ns to 20ns, a pulse energy of 5J to 10J, and a laser spot diameter of not less than 3mm.

7. The apparatus for disassembling partially bonded patches of thin-walled carbon fiber composite materials according to claim 1, characterized in that, It also includes a machine vision module and a computer control module. The machine vision module is used to acquire images of the debonding state of the patch edge of the part to be repaired (1) in real time; the computer control module is connected to the laser shock module, the machine vision module and the adaptive absorber (7) respectively, to coordinate the work of each module.

8. A method for disassembling a partially bonded patch of thin-walled carbon fiber composite material according to any one of claims 1-7, characterized in that, Includes the following steps: The workpiece to be repaired (1) is fixed by the workpiece clamping module, so that the patch disassembly area (101) faces the laser shock module. Apply air pressure to the equal pressure chamber (711) to drive all pin push rods (703) to extend synchronously, so that each absorber head (701) adaptively fits the back of the part to be repaired (1) and the patch removal area at the corresponding position; A pulsed laser is applied to the patch removal area (101) to induce a shock wave that weakens the bonding strength between the patch and the substrate. At the same time, the shock wave energy passing through the substrate is transmitted and dissipated by the absorber (701). Until the edge of the patch is significantly raised or the adhesive layer cracks through, the pressure equalization chamber (711) is depressurized, causing the pin push rod (703) to retract and the detached patch to be removed.

9. The method according to claim 8, characterized in that, Before applying pulsed laser to the patch removal area, a continuous water curtain with a thickness of 2mm to 3mm is first formed on the patch surface as a constraint layer.

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