An in-situ emergency repair method for perforated main load-bearing structures of aircraft made of titanium alloy

Abstract

The present invention provides a method for in-situ emergency repair of perforations in the main load-bearing structure of aircraft made of titanium alloy, which relates to the technical field of aircraft damage repair. The method includes preprocessing the perforations of the aircraft, preparing a prefabricated patch according to the physical state of the perforations after preprocessing, fixing an in-situ repair device in the hole area of the aircraft so that the hole wall of the hole is directly below the welding hole of the in-situ repair device and the centers are aligned; embedding the prefabricated patch into the hole through the welding hole; welding the prefabricated patch and the hole along the contact seam to connect them into a whole, removing the in-situ repair device, and obtaining the repaired aircraft after inspection. The method of the present invention can quickly complete the emergency repair of perforations in the main load-bearing structure of titanium alloy, and the overall strength after repair can be restored to the level of the original component.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft damage repair, and particularly to a method for in-situ emergency repair of perforations in the main load-bearing titanium alloy structure of an aircraft. Background Art

[0002] During the use of an aircraft, there are many threat factors, such as working loads, environmental effects, accidents, human errors, and even attacks. Inevitably, various damages will be encountered. Among them, penetrative perforation is the most typical damage mode.

[0003] Titanium alloy is widely used in the main load-bearing structure of an aircraft because of its high specific strength, high specific stiffness, strong corrosion resistance, and high temperature resistance. Once these components encounter penetrative perforations, their flight capabilities will be directly affected. If not repaired in time, it will greatly delay their reuse.

[0004] Since most of the titanium alloy structures on an aircraft are large in size and are connected in a non-detachable manner, it is generally difficult to perform component replacement repair in the field environment. In order to improve the service efficiency of the aircraft, it is very necessary to study the in-situ rapid emergency repair technology.

[0005] Most of the titanium alloys on an aircraft are α or near-α titanium alloys, and they have good weldability. Therefore, welding is a relatively feasible emergency repair method. However, the traditional arc welding method cannot be used for in-situ welding on the aircraft while being energized, while laser welding can effectively avoid the limitation that welding cannot be carried out on the aircraft while being energized.

[0006] Laser welding uses a high-energy laser beam as a heat source, and has the advantages of high energy density, narrow heat-affected zone, small deformation, and can operate in the atmosphere. It can be implemented by a robot or handheld, which is convenient for field maneuverability. Summary of the Invention

[0007] To solve the above problems, the present invention provides a method for in-situ emergency repair of perforations in the main load-bearing titanium alloy structure of an aircraft. The method of the present invention uses an in-situ repair device to quickly position and embed a prefabricated patch into the perforation, and uses a specific laser welding process to efficiently weld the prefabricated patch into the perforation, achieving the effect of quickly repairing the perforation in-situ without replacing components, with low cost.

[0008] To achieve the technical objectives of the present invention, the present invention provides a method for in-situ emergency repair of perforations in the main load-bearing titanium alloy structure of an aircraft, including:

[0009] Pre-treat the perforation of the aircraft, and prepare a prefabricated patch according to the physical state of the pre-treated perforation, obtaining a hole and a prefabricated patch with the same physical state, and the inner diameter size of the hole is infinitely close to the outer diameter size of the prefabricated patch;

[0010] Fix the in-situ repair device in the hole area of the aircraft so that the hole wall of the hole is directly below the welding hole of the in-situ repair device and centered;

[0011] Insert the prefabricated patch into the hole through the welding hole, making the outer peripheral wall of the prefabricated patch infinitely close to the inner wall of the hole, and the formed contact seam is exposed within the field of view of the welding hole;

[0012] Weld the prefabricated patch and the hole along the contact seam to connect them into a whole, remove the in-situ repair device, and after passing the inspection, obtain the repaired aircraft.

[0013] Among them, the aircraft is in a non-operating state, and the engine and related oil circuits have been disconnected, such as the hydraulic oil and fuel pipelines connected to the airframe, or the engine is directly removed from the damaged fuselage.

[0014] In particular, the perforation is a perforation in the titanium alloy main load-bearing structure.

[0015] Among them, the thickness of the titanium alloy is less than 5 mm.

[0016] Preferably, the thickness of the titanium alloy is 3.5 - 5 mm.

[0017] In particular, the titanium alloy is TC4 alloy or TA15 titanium alloy.

[0018] Among them, the main load-bearing structure is the main load-bearing beam, frame beam, main load-bearing frame, central wing panel, engine tail cover, etc.

[0019] Among them, the inner diameter size of the perforation is 10 mm to 60 mm.

[0020] In particular, the pretreatment is to clean the perforation to make it into a hole with a regular shape.

[0021] Specifically, the cleaning of the perforation includes but is not limited to removing the residual microcracks and edges at the edge of the perforation.

[0022] Specifically, making it into a hole with a regular shape means cleaning the perforation into a circular, oblong or rectangular shape with a specific size rule according to the principle of exceeding 5 mm on one side.

[0023] Furthermore, the size of the hole can be 20 mm, 30 mm, 40 mm, 50 mm and 60 mm. The present invention does not make any restrictions, and those skilled in the art can adjust it according to the actual size of the damage.

[0024] Among them, cleaning the perforation can be to remove the residual microcracks and edges at the edge of the perforation, etc.

[0025] Among them, the hole with a regular shape can be circular, oblong or rectangular, etc.

[0026] In particular, to ensure the complete removal of the damaged part of the perforation, the present invention performs fluorescence detection on the perforation after damage cleaning to ensure that there are no cracks on the surface of the perforation.

[0027] Specifically, the fluorescence detection uses common technologies in aerospace, and the present invention does not limit it. It is based on the wetting and capillary action of liquid on materials. The penetrant containing fluorescent materials is infiltrated into the defects of the workpiece surface opening and adsorbed out. The ultraviolet light is used to excite this part of the penetrant to generate fluorescence, showing the position and size of the defects, and realizing the inspection of the workpiece surface opening defects.

[0028] In particular, the physical state includes but is not limited to the size, thickness, shape, and heat treatment state of the perforation after pretreatment.

[0029] In particular, the in-situ repair device includes:

[0030] A main body member, the main body member has a flat support surface, a groove is provided on the support surface, a pillar is provided on the bottom wall of the groove, and the end surface of the pillar away from the bottom wall and the support surface are in the same plane;

[0031] A fixing mechanism, the fixing mechanism is arranged on the main body member, and the fixing mechanism is used to fix on the structure to be repaired, so that the support surface of the main body member fits the structure to be repaired, and the end surface of the pillar is exposed outside the perforation on the structure to be repaired.

[0032] In some embodiments, the fixing mechanism includes a plurality of fixing arms;

[0033] Each of the fixing arms is arranged on the main body member;

[0034] Each of the fixing arms is arranged in sequence along the circumferential direction of the groove;

[0035] Each of the fixing arms is respectively provided with a tightening member, and the tightening member is used to abut against the rib plate on the structure to be repaired to fix the position of the main body member.

[0036] In some embodiments, the fixing arm includes a first extension arm and a second extension arm;

[0037] The first extension arm is connected to the main body member;

[0038] The second extension arm is connected to the first extension arm, and the second extension arm is perpendicular to the main body member;

[0039] The tightening member is arranged on the second extension arm.

[0040] In some embodiments, a threaded hole is provided on the second extension arm, the pressing component is threadedly connected to the threaded hole, and the pressing component can be rotated to move in a direction perpendicular to the length of the second extension arm.

[0041] In some embodiments, one end of the first extension arm facing away from the second extension arm is movably connected to the main body.

[0042] In some embodiments, a fastener is connected to the main body through the first extension arm;

[0043] The first extension arm can rotate around the fastener, and the fastener can fix the position of the first extension arm.

[0044] In some embodiments, a long slot is provided on the first extension arm;

[0045] The fastener comprises a stud and a cap;

[0046] The stud passes through the elongated slot and is connected to the main body;

[0047] The cap body is limited to the first extension arm.

[0048] In some embodiments, the main body comprises a main board body and a blocking platform disposed on the main board body;

[0049] The blocking platform is arranged on one side of the main board body along the thickness direction;

[0050] The support surface is arranged on the blocking platform;

[0051] The fastener includes a nut;

[0052] The studs penetrate the main board body;

[0053] The nut is threadedly connected to the stud, and the nut and the cap body are respectively limited to two sides of the main board body along the thickness direction.

[0054] In some embodiments, at least two vent holes are provided on the main body;

[0055] Each of the vent holes is connected to the groove.

[0056] In some embodiments, the vent hole is disposed on a side of the main body facing away from the supporting surface.

[0057] The fixing mechanism of the device provided by the present application can be quickly and firmly fixed on the structure to be repaired, and the main body of the clamp can stably support the prefabricated patch at the hole of the structure to be repaired, so as to facilitate the rapid laser welding repair of the damaged part of the hole of the structure to be repaired. The setting of the groove can expose the damaged part of the structure to be repaired, prepare for laser repair, avoid the connection between the structure to be repaired or the patch and the supporting surface during the repair process, and ensure the stability and reliability of the laser repair. The pillar can support the patch, and the shape of the patch is adapted to the shape of the damaged structure to be repaired. The end face of the pillar away from the bottom wall and the supporting surface are located in the same plane. When the end face of the pillar is exposed to the hole on the structure to be repaired, the patch can be supported by the pillar to a position flush with the structure to be repaired, ensuring the accurate and stable repair. The fixing mechanism can be fixed on the structure to be repaired so that the main body can be fixed relative to the position of the structure to be repaired, ensuring the stability of the structure to be repaired during the laser repair process, and ensuring the repair quality of the structure to be repaired. The device of the present application can assist the staff to quickly and effectively perform laser repair on the structure to be repaired, significantly improving the repair quality.

[0058] In particular, before the prefabricated patch is embedded in the hole through the welding hole, the method further comprises:

[0059] Grind the hole area and the area to be welded of the patch to remove the oxide film on the surface;

[0060] Then use alcohol or acetone to remove metal particles or oil stains on the surface.

[0061] The grinding may be performed using any technique in the technical field, and the present invention is not limited thereto. In one embodiment of the present invention, 180-grit sandpaper may be used for grinding.

[0062] The hole area to be welded may be an area extending outward from the inner wall of the hole wall by 1-10 mm.

[0063] The area to be welded of the patch may be an area extending from the outer peripheral wall to the center within 1-10 mm.

[0064] Wherein, the welding process is performed by laser welding.

[0065] In particular, the welding power of the laser welding is 2.8-4.2 KW, the welding speed is 1.1-1.6 m / min, the defocusing amount is 6-18 mm, and the gas flow rate is 10-14 L / min.

[0066] Wherein, after the in-situ repair device is removed, the welded surface is polished and cleaned.

[0067] Among them, the present invention does not limit the grinding and cleaning method, and any one of the existing technologies that can not damage the welding surface, can remove residues such as welding beads on the welding surface, and can pass the appearance inspection can achieve the technical purpose of the present invention.

[0068] Among them, the detection is to perform coloring detection and ultrasonic detection on the welded part.

[0069] The coloring detection and ultrasonic detection are both common technologies in the art to judge whether the internal defects of the welding meet the requirements. The judgment criteria can be determined according to the target requirements, and the present invention does not limit them.

[0070] Beneficial effects

[0071] 1. A method for in-situ emergency repair of holes in the main load-bearing structure of aircraft titanium alloy provided by the present invention solves the problems of long replacement repair cycle and inability to perform in-situ implementation on the aircraft by traditional arc welding. It can quickly complete the emergency repair of holes in the main load-bearing structure of titanium alloy in an emergency environment, and can complete the repair in about 1 hour at the fastest.

[0072] 2. The in-situ repair method provided by the present invention can not only achieve the rapid in-situ repair of typical materials (TC4-M titanium alloy and TA15-M titanium alloy) and typical thicknesses (3.5 mm to 5 mm) of the main load-bearing structure of aircraft titanium alloy by using the in-situ repair device and laser welding process parameters, but also the overall strength after repair can be restored to the level of the original component (about 100%). Brief description of the drawings

[0073] Figure 1 It is a three-dimensional structure schematic diagram of the fixture for in-situ repair provided by the embodiment of the present application;

[0074] Figure 2 It is a side view structure schematic diagram of the fixture for in-situ repair provided by the embodiment of the present application;

[0075] Figure 3 It is a bottom view structure schematic diagram of the fixture for in-situ repair provided by the embodiment of the present application;

[0076] Figure 4 It is a side view perspective structure schematic diagram of the fixture for in-situ repair provided by the embodiment of the present application;

[0077] Figure 5 It is a top view perspective structure schematic diagram of the fixture for in-situ repair provided by the embodiment of the present application;

[0078] Figure 6 It is a structure schematic diagram of the fixture for in-situ repair provided by the embodiment of the present application after being installed on a structure to be repaired;

[0079] Figure 7Structural schematic diagram of a structure to be repaired provided by an embodiment of the present application;

[0080] Figure 8 Structural schematic diagram of a fixture for in-situ repair provided by an embodiment of the present application installed on another structure to be repaired;

[0081] Figure 9 Structural schematic diagram of another structure to be repaired provided by an embodiment of the present application;

[0082] Figure 10 Low-magnification microstructural morphology of TC4 titanium alloy welded joint (parameters 1-3) (×10);

[0083] Figure 11 High-magnification microstructural morphology of TC4 titanium alloy welded joint (parameters 1-3) (×50);

[0084] Figure 12 Fracture morphology of TC4 titanium alloy welded joint (processes A, B, C);

[0085] Figure 13 Low-magnification microstructural morphology of TA15 titanium alloy welded joint (processes D, E) (×10);

[0086] Figure 14 High-magnification microstructural morphology of TA15 titanium alloy welded joint (processes D, E) (×50);

[0087] Figure 15 Fracture morphology of TA15 titanium alloy welded joint (processes D, E).

[0088] In the figure:

[0089] 100, main body; 110, main board; 111, supporting surface; 112, groove; 113, pillar; 120, plug; 130, vent hole; 200, fixing mechanism; 210, fixing arm; 211, first extension arm; 212, second extension arm; 213, threaded hole; 214, long slot; 220, pre-tightening component; 230, fastener; 231, stud; 232, cap; 300, structure to be repaired; 310, rib plate; 320, perforation. Detailed implementation manners

[0090] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation manners.

[0091] Among them, the attached drawings are only for illustrative purposes, showing only schematic diagrams rather than actual physical diagrams, and should not be construed as limiting the present patent; in order to better illustrate the embodiments of the present invention, some components in the attached drawings will be omitted, enlarged or reduced, which does not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the attached drawings may be omitted.

[0092] In the attached drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the attached drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms used to describe the positional relationship in the attached drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0093] In the description of the present invention, unless otherwise clearly specified and defined, if terms such as "connection" are used to indicate the connection relationship between components, this term should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0094] Embodiment 1 In-situ Repair Device

[0095] Refer to Figures 1 to 9 As shown, the embodiment of the present application provides an in-situ repair device, including a main body member 100 and a fixing mechanism 200. The main body member 100 has a flat support surface 111, and a groove 112 is formed on the support surface 111. A support column 113 is provided on the bottom wall of the groove 112, and the end surface of the support column 113 away from the bottom wall is in the same plane as the support surface 111. The fixing mechanism 200 is arranged on the main body member 100 and is used to be fixed on the structure to be repaired 300, so that the support surface 111 of the main body member 100 is attached to the structure to be repaired 300, and the end surface of the support column 113 is exposed outside the hole 320 on the structure to be repaired 300.

[0096] The fixing mechanism of the device provided by the present application can be quickly and firmly fixed to the structure to be repaired. The main body of the fixture can stably support the prefabricated patch at the hole of the structure to be repaired, thus facilitating the rapid laser welding repair of the damaged part of the hole of the structure to be repaired. The groove 112 can expose the damaged part of the structure 300 to be repaired, preparing for laser repair, and avoiding the connection between the structure 300 to be repaired or the patch and the supporting surface 111 during the repair process, ensuring the stable and reliable laser repair. The pillar 113 can support the patch, and the shape of the patch is adapted to the shape of the damaged part of the structure 300 to be repaired. The end face of the pillar 113 away from the bottom wall and the supporting surface 111 are in the same plane. When the end face of the pillar 113 is exposed outside the hole 320 of the structure 300 to be repaired, the patch can be supported to a position flush with the structure 300 to be repaired through the pillar 113, ensuring the accurate and stable repair. The fixing mechanism 200 can be fixed on the structure 300 to be repaired, so that the main body 100 is fixed relative to the structure 300 to be repaired, facilitating the repair operation. The device of the present application can assist the staff to quickly and effectively perform laser repair on the structure to be repaired, significantly improving the repair quality.

[0097] The structure to be repaired in the present application can be a structure on the body that is not easily disassembled. In one embodiment of the present invention, the structure to be repaired can be the main load-bearing structure of an aircraft, such as a main load-bearing beam, a frame beam, a main load-bearing frame, a central wing panel, an engine tail cover, etc. Of course, it can also be other repair structures that need to repair holes, and the present invention is not limited. The device provided by the present application is fixed to the structure to be repaired through the fixing mechanism 200, and the main body 100 is located at the position to be repaired, that is, the position where the structure to be repaired has a hole 320. The fixing mechanism 200 can be specifically fixed on the rib plate 310 of the structure to be repaired. Through the relative fixation of the rib plate 310 and the fixing mechanism 200, the position of the main body 100 can be fixed at the position to be repaired. After fixation, the end face of the pillar 113 of the main body 100 can be exposed outside the hole 320, and the supporting surface 111 abuts against the plate surface of the structure to be repaired.

[0098] See Figures 1 to 4 As shown, in some embodiments of the present application, the fixing mechanism 200 includes a plurality of fixing arms 210. Each fixing arm 210 is arranged on the main body 100, and the fixing arms 210 are sequentially arranged along the circumferential direction of the groove 112. Tightening members 220 are respectively arranged on each fixing arm 210, and the tightening members 220 are used to abut against the rib plate 310 on the structure 300 to be repaired to fix the position of the main body 100.

[0099] Based on the above-mentioned embodiments of the present application, the arrangement of multiple fixing arms 210 can achieve better fixation of the main body 100. The position of the main body 100 can be adjusted according to the position of the broken hole 320, so that the groove 112 on the main body 100 is directly opposite to the broken hole 320, and then each fixing arm is operated so that the fixing arm is fixed on the structure to be repaired. For example, the tightening component 220 on the fixing arm can be adjusted so that the tightening component 220 presses against the plate rib of the structure to be repaired 300. The operator can adjust the tightening components 220 on each fixing arm to press against different positions on the structure to be repaired, so that the main body can be stably fixed at the target position, and the main body 100 will not move easily.

[0100] See also Figures 1 to 6 As shown, in some embodiments of the present application, the fixing arm 210 includes a first extension arm 211 and a second extension arm 212. The first extension arm 211 is connected to the main body 100, the second extension arm 212 is connected to the first extension arm 211, the second extension arm 212 is perpendicular to the main body 100, and the pressing member 220 is disposed on the second extension arm 212.

[0101] Based on the above embodiments of the present application, the first extension arm 211 can be connected to the main body 100, and the second extension arm 212 can fix the main body 100 to the structure to be repaired 300 through the pressing component 220 thereon, so as to achieve the clamping and fixing of the entire clamp. Figure 4 As shown, the plurality of second extension arms 212 can extend to different positions of the structure to be repaired, so that each tightening component 220 can be pressed against different positions respectively, thereby achieving effective fixation of the entire clamp.

[0102] In some embodiments of the present application, see Figure 1 As shown, a threaded hole 213 is provided on the second extension arm 212 , and the pressing component 220 is threadedly connected to the threaded hole 213 . The pressing component 220 can rotate and move along a length direction perpendicular to the second extension arm 212 .

[0103] Based on the above-mentioned embodiments of the present application, the threaded connection between the threaded hole 213 and the clamping component 220 can utilize the self-locking property of the threaded connection to make the fixation of the second extension arm 212 and the rib plate 310 more stable, and the clamping component 220 can be clamped and fixed by rotation, and can be loosened and disassembled by reverse rotation.

[0104] In some embodiments of the present application, one end of the first extension arm 211 away from the second extension arm 212 is movably connected to the main body 100 .

[0105] Based on the above embodiments of the present application, the above structure can make the adjustment range of the fixed arm 210 larger, facilitating the adaptive adjustment of the extension direction and position of each fixed arm 210 according to the specific characteristics of the structure to be repaired, and finally realizing the stable fixation of each fixed arm on the structure to be repaired.

[0106] In specific applications, the position of the main body member 100 can be adjusted first so that the main body member 100 is directly opposite to the broken hole, and then according to the characteristics of the structure on the structure to be repaired, the positions of each fixed arm 210 can be adaptively adjusted respectively, so that the tightening members 220 on the fixed arms 210 can respectively abut against the corresponding structures.

[0107] In some embodiments of the present application, the fastener 230 passes through the first extension arm 211 and is connected to the main body member 100. The first extension arm 211 can rotate around the fastener 230, and the fastener 230 can fix the position of the first extension arm 211.

[0108] Based on the above embodiments of the present application, the fastener 230 can detachably and fixedly connect the first extension arm 211 and the main body member 100. After the first extension arm 211 can rotate around the fastener 230, it can drive the second extension arm 212 to rotate, and further can realize the adjustment of the tightening direction of the tightening member 220 on the second extension arm 212, which can improve the adaptability of the fixture of the present application. When the setting method of some rib plates 310 is unconventional, adaptive adjustment can be realized. The above setting can make the fixing method of the fixing mechanism 200 more diversified.

[0109] In some embodiments of the present application, a long slot 214 is provided on the first extension arm 211. The fastener 230 has a stud 231 and a cap body 232. The stud 231 passes through the long slot 214 and is connected to the main body member 100, and the cap body 232 is limited to the first extension arm 211.

[0110] Based on the above embodiments of the present application, the setting of the long slot 214 can make the first extension arm 211 not only rotate relative to the fastener 230, but also drive the second extension arm 212 to approach or move away from the main body member 100 through the first extension arm 211, further improving the adaptability of the fixing mechanism 200.

[0111] In some embodiments of the present application, the main body member 100 includes a main board body 110 and a plug platform 120 provided on the main board body 110; the plug platform 120 is provided on one side of the main board body 110 along the thickness direction, a support surface 111 is provided on the plug platform 120, the fastener 230 includes a nut portion, the stud 231 of the fastener 230 penetrates through the main board body 110, and the nut portion is threadedly connected to the stud 231. The nut portion and the cap body 232 of the fastener 230 are respectively limited to both sides of the main board body 110 along the thickness direction.

[0112] Based on the above embodiments of the present application, the setting of the plugging platform 120 can reduce the overall thickness of the main board. Relevant parts such as the groove 112 and the support pillar 113 can be arranged on the plugging platform 120. The support pillar 113 is located in the groove 112, and the support pillar 113 is used to support the patch for closing the pre-punching hole 320. The fastener 230 can specifically fixedly connect the first extension arm 211 to the main board body 110. During the specific connection process, a threaded hole 213 can be opened on the main board body 110 so that the fastener 230 can be threadedly connected to the main board body 110. Or a through hole can be opened on the main board body 110, and the fastener 230 is fastened to the main body part through the cooperation of a screw rod, a cap body and a nut part. The screw rod passes through the through hole, and the cap body and the nut part are respectively limited on both sides of the main board body 110 along the thickness direction.

[0113] Further, when the main body part 100 is a square structure, the fixing arms 210 can be respectively arranged at the corners of the main board body 110.

[0114] In some embodiments of the present application, at least two ventilation holes 130 are arranged on the main body part 100, and each ventilation hole 130 communicates with the groove 112. Based on the above embodiments of the present application, the ventilation hole 130 communicating with the groove 112 can facilitate the delivery of inert gas into the groove 112, provide inert gas protection during the laser repair process, improve the repair quality, protect the fixture tooling, and reduce potential safety hazards.

[0115] The in-situ repair of the present application is for in-situ repair of the to-be-repaired structure 300 that is not easily detached from the aircraft. Before repair, the punching hole 320 part of the to-be-repaired structure 300 can be processed, and a patch with a corresponding shape is processed (or the punching hole 320 is processed into the shape of a prefabricated patch), and then it is fixed to the to-be-repaired structure through the in-situ repair device in the present application. The ventilation port can input and output the inert gas in the groove 112.

[0116] The ventilation hole 130 can be arranged on the side of the main body part 100 facing away from the support surface 111, or the ventilation hole 130 can be arranged at other positions of the main body part 100 according to needs, and can be specifically adjusted according to needs.

[0117] The groove 112 of the present application can be a cylindrical groove, and the support pillar 113 can also be a cylindrical support pillar. The diameter of the groove 112 can be 40 mm, and the diameter of the support pillar 113 can be 5 mm, and patches of any size within 40 mm can be placed. Or the diameter of the groove 112 can be 70 mm, and the diameter of the support pillar 113 can be 15 mm, and patches of any size within 70 mm can be placed. The above dimensions are only an exemplary dimension of the present application, and the dimensions can be adjusted according to needs.

[0118] By using the above device, not only the in-situ repair of the aircraft perforation is realized, but also the damaged parts do not need to be disassembled from the aircraft, greatly shortening the repair time.

[0119] Example 2 Method for In-situ Emergency Repair of Perforation in the Main Load-bearing Structure of Aircraft Titanium Alloy

[0120] 1. Preparation operations before repair

[0121] 1.1 Equipment preparation operations

[0122] Move the corresponding laser repair equipment to the part of the aircraft to be repaired; disconnect the hydraulic oil and fuel pipelines connecting the engine to the airframe, and remove the engine from the damaged fuselage.

[0123] 1.2 Preparation operations for the damaged area

[0124] a) Determine the location of the damage, remove the residual microcracks and edges at the edge of the perforation, and clean the perforation into a circular shape (such as 20mm, 30mm, 40mm, 50mm, and 60mm, etc.), oblong or rectangular with a specific size rule of exceeding 5mm on one side. To ensure complete removal of the damage, perform fluorescence detection on the perforation after damage cleaning.

[0125] Specifically, the location of the damage can be determined by visual optical method, assisted by magnetic particle inspection, or other methods in the art that can detect the location of the damage. The present invention does not make limitations.

[0126] It should be noted that the damage mentioned in the present invention mainly refers to perforation damage that affects the main load-bearing structure and maintains the strength of the airframe, especially perforation damage with a size between 10mm and 60mm.

[0127] b) Select a prefabricated patch made of the same material as the repair part or with similar welding strength and welding plasticity, the same heat treatment state, the same thickness, and the same shape and specification.

[0128] It should be noted that the suitable material refers to a material with similar welding strength and welding plasticity, which can be selected through conventional test methods. Among them, the welding strength refers to the strength recovery coefficient, and in one embodiment of the present invention, the material with the best recovery coefficient is selected; the welding plasticity is compared with the plasticity of the original base material, and in one embodiment of the present invention, the closest material is selected. Fix the in-situ repair device provided in Example 1 at the damage location, polish the area within 10mm of the patch and the welding area of the cutting hole with 180-mesh sandpaper to remove the surface oxide film, and then wipe off the metal particles and oil stains with lint-free cloth dipped in alcohol or acetone. If there is no suitable specification in the stock patch, plates with suitable materials and thickness can be selected and prepared on-site by laser cutting.

[0129] 2. In-situ repair

[0130] Select a suitable laser welding process according to the material and thickness of the base material, set the process parameters on the laser welding equipment and teach the welding path; after confirming that the path is correct, weld the prefabricated patch and the hole docking area, and remove the in-situ repair device.

[0131] Specifically, in an embodiment of the present invention, for TC4 titanium alloy base material, the welding power is 3.5 - 4.5 KW, the welding speed is controlled at 1.2 - 2 m / min, the defocus amount is controlled at 13 - 18 m / min, and the gas flow rate is 10 - 14 L / min.

[0132] Furthermore, for TC4 titanium alloy base material, the welding power is 4 KW, the welding speed is controlled at 1.6 m / min, the defocus amount is controlled at 15 m / min, and the gas flow rate is 12 L / min.

[0133] In an embodiment of the present invention, for TA15 titanium alloy base material, the welding power is 3 - 4 KW, the welding speed is controlled at 1 - 1.8 m / min, the defocus amount is controlled at 5 - 7 m / min, and the gas flow rate is 10 - 14 L / min.

[0134] Furthermore, for TA15 titanium alloy base material, the welding power is 3.5 KW, the welding speed is controlled at 1.4 m / min, the defocus amount is controlled at 6 m / min, and the gas flow rate is 12 L / min.

[0135] It should be noted that the laser welding equipment can be any commercially available one or commonly used in the art, and the present invention does not make any restrictions.

[0136] 3. Post - repair treatment

[0137] Use sandpaper or an aluminum brush to remove obvious residues such as weld beads on the weld surface, and then conduct an appearance inspection on the weld. The inspection standard is that the weld surface should be flat, smooth, with smooth transitions on both sides and uniform throughout the entire length of the weld; there are no cracks, pores, burn - throughs, weld beads, undercuts, incomplete penetration, and unfilled crater pits, etc. allowed on the weld surface.

[0138] Appearance inspection can be carried out by coloring inspection (such as fluorescence inspection) and ultrasonic inspection of the weld to determine whether the defects outside and inside the weld meet the requirements.

[0139] The following examples are application examples of using the method of the present invention to repair the perforations of titanium alloy base materials, specifically as follows:

[0140] Application Example 1 Laser Welding of TC4 - M Titanium Alloy Prefabricated Patches

[0141] The method provided in Example 1 was used to in-situ repair the perforations in the main load-bearing structure material TC4 titanium alloy. Among them, the heat treatment state of the perforation treatment was the M state (annealed state), and the thickness was 4 mm. The aperture of the welded specimen was 20 mm. The welding equipment used was MFSC-4000W, and the welding process parameters are shown in Table 1. It can be seen from Table 1 that Process A is within the process range proposed in Example 1 of the present invention; Processes B and C are not within the proposed range, where the power of Process B is lower than the range, and the gas protection of Process C is lower than the range.

[0142] Table 1 Laser welding process parameters for TC4 titanium alloy prefabricated patches

[0143]

[0144] After in-situ repair, a universal testing machine was used to test the strength of the repaired component. The results showed that the tensile strength of the TC4-M base material (undamaged) was 1026 MPa, and the load was 328 KN; after prefabricating a 20-mm diameter perforation, the remaining load was 241 KN, and the remaining strength was 73.5%; the load and strength recovery coefficients after laser welding with prefabricated patches are shown in Table 2.

[0145] It should be noted that the universal testing machine used in the present invention is any commercially available device capable of performing strength tests, and the testing methods are either those given by the device or general testing methods, and the invention does not make any restrictions.

[0146] Table 2 Tensile properties of laser welding of TC4 titanium alloy prefabricated patches

[0147]

[0148] After in-situ repair, the inventor also conducted microscopic observation on the welded joint, and the observation results are as Figures 10 - 12 shown. From Figure 10 the low-magnification structure and Figure 11 the high-magnification structure, it can be seen that the joints are all "I"-shaped, the weld zone is columnar crystal structure, the weld of Process A is the narrowest and the grain size is the smallest; the weld of Process B is slightly wider and there are a small number of pores in the structure; the structure of Process C is coarser and there are more pores.

[0149] From Figure 12 the fracture surface morphology, it can also be seen that for Process A, since the fracture surface is located in the base material, there are no pores; the fracture positions of Processes B and C are both located at the weld, there are certain pores in Process B, and there are a large number of pores in Process C, which verifies the microscopic tissue morphology.

[0150] As can be seen from the above, the method provided by the present invention can repair the perforation to the best state. Especially under the above process conditions, the load at the repaired perforation can be restored from 241 KN to 321 KN, with only a difference of 7 KN from the load of the undamaged base material, restored from 73.5% to 97.8%, the elongation rate is restored to 100%, and the strength recovery coefficient is restored to 98.2%. Moreover, the weld is the narrowest and there are no pores. It can be seen that the repair process of the present invention can achieve the strength recovery of the perforation and has a very good effect.

[0151] However, when using a lower welding power, the strength recovery coefficient is restored to 96%, but the effect is slightly lower than that of the welding process with a power of 4 KW; when using a higher welding power and a lower other flow rate process, the strength recovery coefficient only remains at 46.3%, and the repair of the perforation cannot be achieved.

[0152] Application Example 2 Laser Welding of TA15-M Titanium Alloy Prefabricated Patch

[0153] The method provided in Example 1 was used to in-situ repair the perforations of the main load-bearing structure material TA15 titanium alloy. Among them, the heat treatment state of the perforation treatment was the M state (annealed state), and the thickness was 4 mm. The aperture of the welded specimen was 20 mm. The welding equipment used was MFSC-4000W, and the welding process parameters are shown in Table 3. It can be seen from Table 3 that Process D is the process range proposed in Example 1 of the present invention, and the power of Process E is lower than the range.

[0154] Table 3 Laser Welding Process Parameters of TA15 Titanium Alloy Prefabricated Patch

[0155]

[0156] After in-situ repair, a universal testing machine was used to test the strength of the repaired component. The results showed that the tensile strength of the TA15-M base material (undamaged) was 1109 MPa and the load was 355 KN; the remaining load after prefabricating a 20 mm diameter perforation was 266 KN, and the remaining strength was 74.9%; the load and strength recovery coefficient after laser welding with a prefabricated patch are shown in Table 4.

[0157] Table 4 Tensile Properties of Laser Welding of TA15 Titanium Alloy Prefabricated Patch

[0158]

[0159] After in-situ repair, the welded joint was observed microscopically, and the observation results are as Figures 13 - 15 shown. From Figure 13 the low-magnification structure and Figure 14 the high-magnification structure, it can be seen that the joints are all "I"-shaped, the weld zone is columnar crystal structure, the weld of Process D is the narrowest, the grain size is smaller, and there are no obvious defects inside; the weld of Process E is slightly wider, the structure is coarser, and pores appear.

[0160] From Figure 15 It can also be seen from the fracture morphology that since the fracture of Process D is located in the base metal and there are no pores, and the fracture positions of Process E are all located at the welds. A large number of defects can be seen from the fracture, which verifies the defect morphology of the microstructure.

[0161] In summary, it can be seen that the method provided by the present invention can also repair the perforation of TA15-M titanium alloy to the best state. Especially under the conditions of Process D, the load at the repaired perforation can be restored from 266 KN to 341 KN, the elongation is restored to 98%, the strength recovery coefficient is restored to 96%, and the weld is the narrowest with no pores, and the repair effect is good.

[0162] However, using a lower welding power instead reduces the load at the perforation and cannot repair the perforation.

[0163] It should be noted that the prefabricated patch can be selected in advance for the aircraft material, and multiple sizes can also be prefabricated in advance for its size. After determining the position of the aircraft perforation, a prefabricated patch with a size close to that of the perforation can be selected, and then only the perforation needs to be cut and cleaned, the perforation and the prefabricated patch need to be cleaned before welding, and then welded, which greatly shortens the time. According to statistics, the perforation repair can be completed in as fast as 1 hour.

[0164] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art of this patent, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to the above-mentioned technical content using the disclosed technical content as equivalent change equivalent embodiments. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the invention.

Claims

1. A method for in-situ emergency repair of perforated titanium alloy main load-bearing structures of an aircraft, characterized in that, include: Pre-treating the hole in the aircraft, and preparing a prefabricated patch according to the physical state of the pre-treated hole, so as to obtain a hole and a prefabricated patch with the same physical state, and the inner diameter of the hole is infinitely close to the outer diameter of the prefabricated patch; Fix the in-situ repair device to the hole area of the aircraft so that the hole wall is directly below the welding hole of the in-situ repair device and the center is aligned; The prefabricated patch is embedded in the hole through the welding hole, so that the outer peripheral wall of the prefabricated patch is infinitely close to the inner wall of the hole, and the formed contact seam is exposed in the field of vision of the welding hole; The prefabricated patch and the hole are welded along the contact seam to form a whole, the in-situ repair device is removed, and after passing the inspection, the repaired aircraft is obtained; Among them, the in-situ repair device includes: a main body, the main body has a flat supporting surface, a groove is opened on the supporting surface, a pillar is arranged on the bottom wall of the groove, and the end surface of the pillar facing away from the bottom wall is located in the same plane as the supporting surface; a fixing mechanism, the fixing mechanism is arranged on the main body, and the fixing mechanism is used to be fixed on the structure to be repaired, so that the supporting surface of the main body is in contact with the structure to be repaired, and the end surface of the pillar is exposed in the hole on the structure to be repaired.

2. The in-situ emergency repair method according to claim 1, characterized in that The broken holes are broken holes in the main load-bearing structure of the titanium alloy, and the thickness of the titanium alloy is less than 5 mm.

3. The in-situ emergency repair method according to claim 1, characterized in that, The holes are holes in the main load-bearing structure of the titanium alloy, and the thickness of the titanium alloy is 3.5-5 mm.

4. The in-situ emergency repair method according to claim 1, characterized in that, The broken holes are broken holes in the main load-bearing structure of the titanium alloy, and the titanium alloy is TC4 alloy or TA15 titanium alloy.

5. The in-situ emergency repair method according to claim 1, wherein The main load-bearing structure is a main load-bearing beam, a mouth frame beam, a main load-bearing frame, a central wing wall panel, and an engine tail cover.

6. The in-situ emergency repair method according to claim 1, characterized in that, The inner diameter of the hole is 10 mm to 60 mm.

7. The in-situ emergency repair method according to claim 1, wherein, The pretreatment is to clean the broken holes and turn them into holes with regular shapes.

8. The in-situ emergency repair method according to claim 7, wherein, The regularly shaped holes are circular, oblong or rectangular.

9. The in-situ emergency repair method according to claim 1, characterized in that, The pretreatment further comprises performing fluorescence detection on the pores.

10. The in-situ emergency repair method according to claim 9, characterized in that, The fluorescence detection is to detect cracks on the surface of the hole.

11. The in-situ emergency repair method according to claim 1, characterized in that, The physical state includes but is not limited to the size, thickness, shape, and heat treatment state of the pre-treated holes.

12. The in-situ emergency repair method according to claim 1, wherein, The fixing mechanism includes a plurality of fixing arms; each of the fixing arms is arranged on the main body; each of the fixing arms is arranged in sequence along the circumference of the groove; each of the fixing arms is provided with a tightening component, and the tightening component is used to press against the rib plate on the structure to be repaired to fix the position of the main body.

13. The in-situ emergency repair method according to claim 12, characterized in that, The fixed arm includes a first extension arm and a second extension arm; the first extension arm is connected to the main body; the second extension arm is connected to the first extension arm, and the second extension arm is perpendicular to the main body; the tightening component is arranged on the second extension arm.

14. The in-situ emergency repair method according to claim 13, characterized in that, The second extension arm is provided with a threaded hole, the pressing component is threadedly connected to the threaded hole, and the pressing component can be rotated to move along a length direction perpendicular to the second extension arm.

15. The in-situ emergency repair method according to claim 13, wherein, One end of the first extension arm facing away from the second extension arm is movably connected to the main body.

16. The in-situ emergency repair method according to claim 13, characterized in that, The fastener passes through the first extension arm and is connected to the main body; the first extension arm can rotate around the fastener, and the fastener can fix the position of the first extension arm.

17. The in-situ emergency repair method according to claim 16, wherein, A long slot is provided on the first extension arm; the fastener has a stud and a cap body; the stud passes through the long slot and is connected to the main body; the cap body is limited to the first extension arm.

18. The in-situ emergency repair method according to claim 17, characterized in that, The main body includes a main board body and a plug platform provided on the main board body; the plug platform is provided on one side of the main board body in the thickness direction; the support surface is provided on the plug platform; the fastener includes a nut; the stud penetrates through the main board body; the nut is threadedly connected to the stud, and the nut and the cap body are respectively limited to both sides of the main board body in the thickness direction.

19. The in-situ emergency repair method according to claim 1, characterized in that, At least two ventilation holes are provided on the main body; each ventilation hole communicates with the groove.

20. The in-situ emergency repair method according to claim 19, characterized in that, The ventilation holes are provided on the side of the main body facing away from the support surface.

21. The in-situ emergency repair method according to claim 1, characterized in that, Before the prefabricated patch is embedded in the hole through the welding hole, it further includes: Grinding the hole area and the welding area of the patch to remove the oxide film on the surface. Using alcohol or acetone to remove metal particles and oil stains on the surface.

22. The in-situ emergency repair method according to claim 21, wherein, The welding area of the hole area is the area within 1 - 15 mm extending outward from the inner wall of the hole wall.

23. The in-situ emergency repair method according to claim 21, characterized in that, The welding area of the patch is the area within 5 - 15 mm extending from the outer peripheral wall to the center.

24. The in-situ emergency repair method according to claim 1, characterized in that, The welding treatment is carried out by laser welding.

25. The in-situ emergency repair method according to claim 24, wherein, The welding power of the laser welding is 2.8 - 4.2 KW, the welding speed is 1.1 - 1.6 m / min, the defocus amount is 6 - 18 mm, and the gas flow rate is 10 - 14 L / min.

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