Method and device for strengthening and prolonging service life of chamfers with different curvatures of force bearing component of aircraft

Abstract

The invention discloses a method and a device for strengthening and prolonging the service life of chamfers with different curvatures of an aircraft force-bearing component. The method comprises the following steps: measuring the curvature of the chamfers of the aircraft aluminum alloy force-bearing component; spraying a composite high polymer material absorbing layer with uniform thickness on the surfaces of chamfers with different curvatures of the aircraft aluminum alloy bearing component; stress field distribution is formulated according to chamfer shape topological optimization, and a laser shock path, the laser spot size and energy are calculated; adding a restraint layer on the surface of the chamfer in a water layer soaking mode and controlling the restraint layer to be a constant value in real time; according to the mechanical arm fixing component, laser shock is adopted to impact the chamfered surface based on a laser shock path, gradient light spots are arranged according to different chamfered curvatures, and the size of the light spots and laser energy are adjusted in a shape follow-up mode; removing the restraint layer and the absorption layer after the impact is finished, and checking the surface of the component; the absorption layer and the restraint layer are added during chamfering laser strengthening, and the efficiency of laser shock strengthening and service life prolonging is improved through laser path planning and gradient light spot size and energy setting.

Description

Technical Field

[0001] The invention relates to the technical field of metal surface strengthening, and more particularly to a method and device for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers. Background Art

[0002] Aluminum alloy high-rib components have the advantages of high strength, high rigidity and light weight. They are currently widely used in load-bearing structures in major equipment fields such as aerospace. However, during the docking and assembly process of the ribs and cover plates of the load-bearing parts, defects such as delamination and porosity are prone to occur in the chamfered area. In addition, due to the different wall thicknesses and load-bearing sizes in the chamfered area, stress concentration is easily generated, leading to the generation and expansion of fatigue cracks. Therefore, the quality of the chamfered area plays a vital role in the overall component. In the actual repair process, after a small fatigue crack occurs in the component, it is repaired by reinforcement. However, if the crack is large, the entire component needs to be replaced. It can be seen that it is difficult to repair fatigue cracks. Therefore, it is necessary to improve the fatigue resistance of the chamfered area and extend the fatigue life.

[0003] Regarding the strengthening of the chamfered area, Chinese patent CN202110329928.4 discloses a method of cold extrusion strengthening and shot peening strengthening of the chamfered area, but it is limited to the strengthening of the chamfer between the stack and the hole of the two alloys, and has high requirements on the size of the alloy bonding surface, dimensional matching clearance, etc. of the material, and it is also necessary to accurately sort the processing and assembly processes of the required parts, which involves a long process.

[0004] Chamfers of aircraft aluminum alloy load-bearing components with different curvatures are prone to stress concentration, which leads to the generation and expansion of fatigue cracks. Therefore, laser shock strengthening can be used for precise local strengthening to regulate the mechanical properties of different areas, increase the uniformity between areas, thereby improving the fatigue resistance of components and extending fatigue life. However, since it is difficult to add absorption layers and constraint layers in the chamfered area and there is no reasonable laser shock path planning method, there is currently no method for laser shock strengthening and life extension of chamfers with different curvatures of aircraft load-bearing components.

[0005] Therefore, how to provide laser shock strengthening for aircraft aluminum alloy load-bearing components with different curvature chamfers so as to improve the fatigue resistance of the chamfered area and extend the fatigue life is an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0006] In view of this, the present invention provides a method and device for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers to solve some of the technical problems mentioned in the background technology.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A method for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers, comprising the following steps:

[0009] S1. Measure the chamfer curvature of aircraft aluminum alloy load-bearing components;

[0010] S2. Using composite polymer materials and spraying to prepare an absorption layer of uniform thickness on the chamfered surfaces of different curvatures of aircraft aluminum alloy load-bearing components;

[0011] S3. According to the topological optimization of the specific chamfer shape of the aircraft aluminum alloy load-bearing components, the stress field distribution is formulated, and the laser impact path, laser spot size and energy are calculated;

[0012] S4. Select water as the laser impact constraint layer, immerse the chamfered area of ​​the aluminum alloy load-bearing component to be strengthened, so that the constraint layer evenly covers the surface to be strengthened, and control the distance between the chamfer of the component and the surface of the water layer to be a constant value in real time;

[0013] S5. After the absorption layer is formed on the surface of the component, it is clamped and fixed on the manipulator with a special tool, and the laser impact equipment is started. Based on the laser impact path, the chamfered surfaces of the aluminum alloy load-bearing components with different curvatures are impacted. According to the different chamfered curvatures, a gradient spot is set, and the spot size and laser energy are adjusted according to the shape during the laser impact process;

[0014] S6. After the impact, remove the constraint layer and the absorption layer and inspect the surface of the component.

[0015] Preferably, before step S1, the process also includes pre-treating and ultrasonically cleaning the chamfered surfaces of the aircraft aluminum alloy load-bearing components.

[0016] Preferably, after step S5, the process also includes grinding and polishing the surface of the component to control the roughness to meet the use standard.

[0017] Preferably, in step S2, the composite polymer material absorption layer used for laser shock is divided into two layers, which is achieved by secondary spraying.

[0018] Preferably, the first layer of the absorption layer is a base layer with a thickness of 0.08-0.12 mm; the second layer is an impact layer with a thickness of 0.2-0.3 mm.

[0019] Preferably, the main component of the composite polymer material is epoxy resin.

[0020] Preferably, the laser path planning and energy size in step S3 are set according to the stress field formulated by the specific shape topology optimization. On the path of laser movement, when the chamfer curvature changes, the size of the spot and the laser energy both change: when the chamfer curvature becomes smaller, the spot diameter and the laser energy both decrease; when the chamfer curvature becomes larger, the spot diameter and the laser energy both increase.

[0021] Preferably, in step S4, the thickness of the constrained layer on the surface to be strengthened is accurately controlled within the range of 1-2 mm by adjusting the position of the manipulator and the amount of water.

[0022] A device for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers, based on the method for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers, comprises:

[0023] Chamfer curvature measurement structure, used to measure the chamfer curvature of aircraft aluminum alloy load-bearing components;

[0024] The absorption layer spraying structure is used to prepare an absorption layer with uniform thickness on the chamfered surfaces of different curvatures of aircraft aluminum alloy load-bearing parts by using composite polymer materials and spraying;

[0025] The calculation control module is used to formulate the stress field distribution according to the topological optimization of the specific chamfer shape of the aircraft aluminum alloy load-bearing components, calculate the laser impact path, laser spot size and energy, and write the control program;

[0026] A water nozzle is used to select water as a laser impact constraint layer, immerse the chamfered area of ​​the aluminum alloy load-bearing component to be strengthened, so that the constraint layer evenly covers the surface to be strengthened, and controls the distance between the component chamfer and the water layer surface to be a constant value in real time;

[0027] A manipulator, which is used to clamp and fix the component with a special tool after the layer to be absorbed is formed on the surface of the component;

[0028] The laser impact equipment is used to impact the chamfered surfaces of aluminum alloy load-bearing components with different curvatures through a laser based on the laser impact path under the control program of the computing control module, and to set a gradient spot according to the different chamfer curvatures, and to adjust the spot size and laser energy according to the shape during the laser impact process.

[0029] Preferably, the device for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers further comprises a pretreatment cleaning structure and a polishing and grinding structure;

[0030] Pretreatment and cleaning structure, used for pretreatment and ultrasonic cleaning of chamfered surfaces of aircraft aluminum alloy load-bearing parts;

[0031] The grinding and polishing structure is used to grind and polish the surface of the component after impact to control the roughness to meet the use standard.

[0032] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method and device for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers, which can effectively improve the fatigue resistance of the components and extend the fatigue life; a composite polymer material is used as the absorption layer for laser shock life extension, which solves the problem that it is difficult to balance the bonding strength and impact resistance of the absorption layer in the chamfered area of ​​aircraft aluminum alloy load-bearing components with different curvatures, and the operation is convenient and the stability is good; laser path planning and energy size setting are carried out according to the stress field customized by specific shape topology optimization, and a gradient light spot that moves with the movement is set according to the different curvatures of the chamfers, which meets the light spot coverage requirements of the strengthening area; a constraint layer for laser shock life extension is added by immersing in a water layer and controlling the water layer thickness in real time in situ, which solves the problem that it is difficult to add a constraint layer in the chamfered area of ​​aircraft aluminum alloy load-bearing components with different curvatures during laser shock. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0034] Figure 1 A schematic diagram of a method for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers provided by the present invention;

[0035] Figure 2 A schematic diagram of a device for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers provided by the present invention;

[0036] Figure 3 A schematic diagram of hardness data of chamfered areas of aircraft aluminum alloy load-bearing components with different curvatures before and after laser shock strengthening provided by an embodiment of the present invention;

[0037] Figure 4 A schematic diagram of residual stress data before and after laser shock strengthening of chamfered areas of aircraft aluminum alloy load-bearing components with different curvatures provided by an embodiment of the present invention;

[0038] Figure 5 A schematic diagram of fatigue life test data of chamfered areas of aircraft aluminum alloy load-bearing components with different curvatures before and after laser shock strengthening provided by an embodiment of the present invention;

[0039] Among them, 1- chamfer curvature measurement structure, 2- pretreatment cleaning structure, 3- grinding and polishing structure, 4- absorption layer spraying structure, 5- calculation control module, 6- laser impact equipment, 7- manipulator, 8- laser device, 9- water nozzle. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Embodiment 1

[0042] The embodiment of the present invention discloses a method for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers, such as Figure 1 , including the following steps:

[0043] S1. Measure the chamfer curvature of aircraft aluminum alloy load-bearing components;

[0044] S2. Using composite polymer materials and spraying to prepare an absorption layer of uniform thickness on the chamfered surfaces of different curvatures of aircraft aluminum alloy load-bearing components;

[0045] S3. According to the topological optimization of the specific chamfer shape of the aircraft aluminum alloy load-bearing components, the stress field distribution is formulated, and the laser impact path, laser spot size and energy are calculated;

[0046] S4. Select water as the laser impact constraint layer, immerse the chamfered area of ​​the aluminum alloy load-bearing component to be strengthened, so that the constraint layer evenly covers the surface to be strengthened, and control the distance between the chamfer of the component and the surface of the water layer to be a constant value in real time;

[0047] S5. After the absorption layer is formed on the surface of the component, it is clamped and fixed on the manipulator with a special tool, and the laser impact equipment is started. Based on the laser impact path, the chamfered surfaces of the aluminum alloy load-bearing components with different curvatures are impacted. According to the different chamfered curvatures, a gradient spot is set, and the spot size and laser energy are adjusted according to the shape during the laser impact process;

[0048] S6. After the impact, remove the constraint layer and the absorption layer and inspect the surface of the component.

[0049] In order to further implement the above technical solution, before step S1, the chamfered surface of the aircraft aluminum alloy load-bearing component is also pre-treated and ultrasonically cleaned.

[0050] In order to further implement the above technical solution, step S5 also includes grinding and polishing the surface of the component to control the roughness to meet the use standard.

[0051] In order to further implement the above technical solution, in step S2, the composite polymer material absorption layer used for laser shock is divided into two layers, which is achieved by secondary spraying.

[0052] In practical applications, the sprayed composite absorption layer is required to have good bonding strength and uniformity, and its overall thickness is 0.3-0.4mm. The specific thickness is determined by the laser impact energy.

[0053] In order to further implement the above technical scheme, the first layer of the absorption layer is a base layer with a thickness of 0.08-0.12mm, the purpose of which is to improve the bonding strength of the absorption layer; the second layer is an impact layer with a thickness of 0.2-0.3mm, which must have good impact resistance to meet the requirements of the laser shock absorption layer.

[0054] In order to further implement the above technical solution, the main component of the composite polymer material is epoxy resin.

[0055] In order to further implement the above technical solution, the laser path planning and energy size in step S3 are set according to the stress field formulated by the specific shape topology optimization. On the path of laser movement, when the chamfer curvature changes, the size of the spot and the laser energy change: when the chamfer curvature becomes smaller, the spot diameter and the laser energy both decrease; when the chamfer curvature becomes larger, the spot diameter and the laser energy both increase. The specific spot size and energy vary with the component material, the number of strengthening times, etc.

[0056] In order to further implement the above technical solution, in step S4, the thickness of the constrained layer on the surface to be strengthened is accurately controlled within the range of 1-2 mm by adjusting the position of the manipulator and the amount of water. The water can be pure water, deionized water, etc.

[0057] Embodiment 2

[0058] A device for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers, such as Figure 2 , based on a method for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers, including:

[0059] Chamfer curvature measurement structure, used to measure the chamfer curvature of aircraft aluminum alloy load-bearing components;

[0060] The absorption layer spraying structure is used to prepare an absorption layer with uniform thickness on the chamfered surfaces of different curvatures of aircraft aluminum alloy load-bearing parts by using composite polymer materials and spraying;

[0061] The calculation control module is used to formulate the stress field distribution according to the topological optimization of the specific chamfer shape of the aircraft aluminum alloy load-bearing components, calculate the laser impact path, laser spot size and energy, and write the control program;

[0062] A water nozzle is used to select water as a laser impact constraint layer, immerse the chamfered area of ​​the aluminum alloy load-bearing component to be strengthened, so that the constraint layer evenly covers the surface to be strengthened, and controls the distance between the component chamfer and the water layer surface to be a constant value in real time;

[0063] A manipulator, which is used to clamp and fix the component with a special tool after the layer to be absorbed is formed on the surface of the component;

[0064] The laser impact equipment is used to impact the chamfered surfaces of aluminum alloy load-bearing components with different curvatures through laser based on the laser impact path under the control program of the computing control module, and set the gradient spot according to the different chamfer curvatures, and adjust the spot size and laser energy according to the shape during the laser impact process.

[0065] In order to further implement the above technical solution, a device for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers also includes a pretreatment cleaning structure and a polishing and grinding structure;

[0066] Pretreatment and cleaning structure, used for pretreatment and ultrasonic cleaning of chamfered surfaces of aircraft aluminum alloy load-bearing parts;

[0067] The grinding and polishing structure is used to grind and polish the surface of the component after impact to control the roughness to meet the use standard.

[0068] Embodiment 3

[0069] The material of the aircraft aluminum alloy load-bearing component to be strengthened in this embodiment is 7050 aluminum alloy, and the chamfer curvature R is 3 mm.

[0070] Laser shock strengthening is performed using a strengthening and life extension method for chamfers with different curvatures of aircraft load-bearing components provided by the present invention. The absorption layer used for laser shock is a composite polymer material, which is divided into two layers and is achieved through secondary spraying. The first layer of the composite absorption layer is a base layer with a thickness of 0.08 mm, and the second layer is an impact layer with a thickness of 0.2 mm. After path planning is performed according to the stress field distribution specified by the topological optimization of the chamfer shape of the component to be strengthened, the laser energy is set to 8 J, a circular spot is used, and the spot size is 1.5 mm. A program is written and imported into the laser control end, and impact is performed once along the set path. Deionized water is used as a constraint layer for laser shock, and the distance between the chamfer of the component and the surface of the water layer is controlled to be 1 mm in real time in situ during the strengthening process.

[0071] The Vickers hardness tester was used to measure the surface hardness of the chamfer after laser shock strengthening, which was slightly increased from 170HV before strengthening to 188HV, an increase of 10.59% compared with before strengthening. Figure 3 ; The X-ray residual stress tester measured that the residual stress on the chamfered surface after laser shock changed significantly, and the compressive stress increased from -103MPa before strengthening to -313MPa. Figure 4According to the fatigue test results, when the maximum stress is 150MPa and the stress ratio R=0.1, the fatigue life of the sample after laser shock strengthening can be increased from 211,000 cycles to 442,000 cycles, which is 109% higher than the life of the original sample. Figure 5 .

[0072] Embodiment 4

[0073] The material of the aircraft aluminum alloy load-bearing component to be strengthened in this embodiment is 7050 aluminum alloy, and the chamfer curvature R is 5 mm.

[0074] Laser shock strengthening is performed using a strengthening and life extension method for chamfers with different curvatures of aircraft load-bearing components provided by the present invention. The absorption layer used for laser shock is a composite polymer material, which is divided into two layers and is achieved through secondary spraying. The first layer of the composite absorption layer is a base layer with a thickness of 0.12 mm; the second layer is an impact layer with a thickness of 0.25 mm. After path planning is performed according to the stress field distribution specified by the topological optimization of the chamfer shape of the component to be strengthened, the laser energy is set to 10 J, a circular spot is used, and the spot size is 2 mm. A program is written and imported into the laser control end, and shocks are performed 3 times along the set path. Deionized water is used as a constraint layer for laser shock, and the distance between the chamfer of the component and the surface of the water layer is controlled to be 1 mm in real time in situ during the strengthening process.

[0075] The Vickers hardness tester was used to measure the surface hardness of the chamfer after laser shock strengthening, which was slightly increased from 174HV before strengthening to 195HV, an increase of 12.07% compared with before strengthening. Figure 3 The X-ray residual stress tester was used to measure the residual stress of the chamfered surface after laser shock. The compressive stress increased from -116MPa before strengthening to -335MPa. Figure 4 According to GB / T6398-2000 standard, the fatigue crack growth test results of the CT fatigue specimen with an opening length of 10 mm and a prefabricated crack of 2 mm showed that the fatigue life of the original specimen was 1.753×10 5 The crack length is 21.2 mm after cycles; the fatigue life is increased to 2.303×10 5 After the first cycle, the crack length was 23.4 mm, which was 31.4% longer than the original specimen. Figure 5 .

[0076] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0077] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for strengthening and extending the life of aircraft load-bearing components by chamfering with different curvatures, characterized in that: The following steps are involved: S1. Measure the chamfer curvature of aircraft aluminum alloy load-bearing components; S2. Using composite polymer materials and spraying them on the surfaces of different curvature chamfers of aircraft aluminum alloy load-bearing parts to prepare an absorption layer with uniform thickness; S3. According to the topological optimization of the specific chamfer shape of the aircraft aluminum alloy load-bearing components, the stress field distribution is formulated, and the laser impact path, laser spot size and energy are calculated; S4. Select water as the laser impact constraint layer, immerse the chamfered area of ​​the aluminum alloy load-bearing component to be strengthened, so that the constraint layer evenly covers the surface to be strengthened, and control the distance between the chamfer of the component and the surface of the water layer to be a constant value in real time; S5. After the absorption layer is formed on the surface of the component, it is clamped and fixed on the manipulator with a special tool, and the laser impact equipment is started. Based on the laser impact path, the chamfered surfaces of the aluminum alloy load-bearing components with different curvatures are impacted. According to the different chamfered curvatures, a gradient spot is set, and the spot size and laser energy are adjusted according to the shape during the laser impact process; S6. After the impact, remove the constraint layer and the absorption layer and inspect the surface of the component.

2. The method for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers according to claim 1, characterized in that: Before step S1, the process also includes pre-treating and ultrasonically cleaning the chamfered surfaces of the aircraft aluminum alloy load-bearing components.

3. The method for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers according to claim 1, characterized in that: After step S5, the process also includes grinding and polishing the surface of the component to control the roughness to meet the use standard.

4. The method for strengthening and extending the life of aircraft load-bearing components by chamfering with different curvatures according to claim 1, characterized in that: In step S2, the composite polymer material absorption layer used for laser shock is divided into two layers, which is achieved by secondary spraying.

5. The method for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers according to claim 4, characterized in that: The first layer of the absorption layer is the base layer with a thickness of 0.08-0.12mm; the second layer is the impact layer with a thickness of 0.2-0.3mm.

6. The method for strengthening and extending the life of aircraft load-bearing components by chamfering with different curvatures according to claim 1, characterized in that: The main component of composite polymer materials is epoxy resin.

7. The method for strengthening and extending the life of aircraft load-bearing components by chamfering with different curvatures according to claim 1, characterized in that: The laser path planning and energy size in step S3 are set according to the stress field formulated by the specific shape topology optimization. On the path of laser movement, when the chamfer curvature changes, the size of the spot and the laser energy change: when the chamfer curvature becomes smaller, the spot diameter and the laser energy both decrease; when the chamfer curvature becomes larger, the spot diameter and the laser energy both increase.

8. The method for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers according to claim 1, characterized in that: In step S4, the thickness of the constrained layer on the surface to be strengthened is accurately controlled within the range of 1-2 mm by adjusting the position of the manipulator and the amount of water.

9. A device for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers, characterized in that: A method for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers based on any one of claims 1 to 8, comprising: Chamfer curvature measurement structure, used to measure the chamfer curvature of aircraft aluminum alloy load-bearing components; The absorption layer spraying structure is used to prepare an absorption layer with uniform thickness on the chamfered surfaces of different curvatures of aircraft aluminum alloy load-bearing parts by using composite polymer materials and spraying; The calculation control module is used to formulate the stress field distribution according to the topological optimization of the specific chamfer shape of the aircraft aluminum alloy load-bearing components, calculate the laser impact path, laser spot size and energy, and write the control program; A water nozzle is used to select water as a laser impact constraint layer, immerse the chamfered area of ​​the aluminum alloy load-bearing component to be strengthened, so that the constraint layer evenly covers the surface to be strengthened, and controls the distance between the component chamfer and the water layer surface to be a constant value in real time; A manipulator, which is used to clamp and fix the component with a special tool after the layer to be absorbed is formed on the surface of the component; The laser impact equipment is used to impact the chamfered surfaces of aluminum alloy load-bearing components with different curvatures through laser based on the laser impact path under the control program of the computing control module, and set the gradient spot according to the different chamfer curvatures, and adjust the spot size and laser energy according to the shape during the laser impact process.

10. The device for strengthening and extending the life of aircraft load-bearing components with different curvature chamfers according to claim 9, characterized in that: It also includes a pre-treatment cleaning structure and a polishing and grinding structure; Pretreatment and cleaning structure, used for pretreatment and ultrasonic cleaning of chamfered surfaces of aircraft aluminum alloy load-bearing parts; The grinding and polishing structure is used to grind and polish the surface of the component after impact to control the roughness to meet the use standard.

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