Stress regulation and control and welding deformation control method for small aero-engine combustion chamber

Abstract

The invention discloses a stress regulation and control and welding deformation control method for a small aero-engine combustion chamber, and the method comprises the steps of using a universal welding clamp, coating high-strength peelable coatings along the two sides of a welding section, and adopting a welding path self-adaptive algorithm. The universal welding clamp is used for fixing a thin-wall part of the combustion chamber and applying prestress; pre-loading force is applied to the welding part through a multi-dimensional adjustable pre-loading device, so that thermal deformation generated in the welding process is partially counteracted; the high-strength peelable coating is brushed on the two sides of a welding section, is formed by compounding a high-temperature stable resin base material, reinforced fibers, an inorganic nano heat stabilizer and ceramic microspheres, has high strength and setting capacity after being cured, is used for limiting thermal expansion and cold contraction stress deformation of a welding area, and is integrally torn off without leaving residues after welding is completed; the invention provides a systematized and intelligent welding stress regulation and deformation control method which is particularly suitable for the high-precision welding requirement of a combustion chamber of a small aero-engine.

Description

Technical Field

[0001] The present invention belongs to the technical field of welding, and particularly relates to a stress regulation and welding deformation control method for a small aero-engine combustion chamber. Background Art

[0002] A small aero-engine combustion chamber is usually made of superalloy or heat-resistant metal materials, with a thin-wall structure that is complex and requires high strength and high precision. However, during the welding process, due to the non-uniformity of heat input, significant thermal expansion and contraction effects often occur, resulting in residual stress concentration and structural deformation in the welding area. The difficulty in controlling such welding stress and deformation has become the main problem affecting the performance and life of the combustion chamber.

[0003] Existing Control Methods for Welding Stress and Deformation

[0004] Heat treatment process: Overall post-weld heat treatment or local thermal correction is adopted to release residual stress. However, this method is time-consuming and energy-consuming, and may cause secondary damage to thin-wall parts, affecting dimensional accuracy.

[0005] Welding path optimization: Currently, most welding paths are preset paths, which are difficult to adapt to the stress and deformation changes generated during the welding process in real time, lacking dynamic optimization capabilities, resulting in stress concentration and welding defects.

[0006] Lack of Intelligent Control

[0007] The existing welding process lacks an intelligent stress monitoring and feedback system. The optimization of welding paths and parameters relies on manual experience, with poor process consistency and difficulty in meeting the high-precision welding requirements of complex thin-wall parts. Summary of the Invention

[0008] Therefore, the purpose of the present invention is to provide a stress regulation and welding deformation control method for a small aero-engine combustion chamber, providing a systematic and intelligent welding stress regulation and deformation control method, which is particularly suitable for the high-precision welding requirements of a small aero-engine combustion chamber.

[0009] To solve the above technical problems, according to one aspect of the present invention, the following technical solutions are provided:

[0010] A stress regulation and welding deformation control method for a small aero-engine combustion chamber, the method comprising a welding universal fixture, a high-strength peelable coating applied on both sides along the welding section, and a welding path adaptive algorithm:

[0011] Welding universal fixture: Used to fix the thin-wall parts of the combustion chamber and apply prestress. A multi-dimensional adjustable preloading device is used to apply a preloading force on the welded parts to partially offset the thermal deformation generated during the welding process;

[0012] High-strength peelable coating: The coating is applied on both sides of the welding cross-section and is composed of a high-temperature stable resin substrate, reinforcing fibers, inorganic nano thermal stabilizers, and ceramic microspheres. After curing, it has high strength and shaping ability, is used to limit the thermal expansion and contraction stress deformation in the welding area, and can be torn off as a whole after welding without leaving residues;

[0013] Welding path adaptive algorithm: It is used to optimize the welding path. By real-time monitoring the stress and deformation data of the welded parts, it dynamically adjusts the welding speed, heat input, and path trajectory to ensure uniform heat input and optimized stress distribution during welding, reducing welding deformation and defects.

[0014] Preferably, the welding path adaptive algorithm forms an adaptive closed-loop control system by real-time collecting the stress and deformation data of the welded parts and dynamically optimizing the welding path, heat input, and speed based on machine learning algorithms.

[0015] Preferably, the welding path adaptive algorithm pre-generates an initial welding path according to the geometric shape and material properties of the welded parts and adjusts the path during welding according to real-time feedback to balance the welding stress.

[0016] Preferably, the welding universal fixture works in coordination with the welding path adaptive algorithm to dynamically adjust the preloading force and welding path trajectory during welding to further optimize the stress distribution during welding.

[0017] Preferably, the welding path adaptive algorithm includes the following steps:

[0018] S1. Initial path planning

[0019] Use finite element analysis (FEA) to predict the stress distribution of the welded parts and generate the initial path P 0 ;

[0020]

[0021] Among them, P: welding path; σ res (x, y, z): Welding residual stress distribution function, unit: MPa; x, y, z: Spatial coordinates, unit: mm; dL: Welding path microelement length, unit: mm;

[0022] S2. Real-time monitoring and feedback

[0023] Use sensors to obtain stress σ real and deformation δ real data in real time:

[0024] σ real = f σ (t), δ real = f δ(t);

[0025] Among them, σ real : Real-time stress, unit: MPa; δ real : Real-time deformation, unit: mm; t: Time, unit: s; f σ (t), f δ (t): Time function of stress and deformation;

[0026] S3. Path dynamic adjustment

[0027] Calculate the real-time path adjustment amount ΔP:

[0028] ΔP = β × (σ real - σ target );

[0029] Among them, ΔP: Path adjustment amount, unit: mm; β: Adjustment coefficient, value range 0.1 - 1.0; σ target : Target stress, value range is 30% - 70% of the yield strength of the welded part;

[0030] S4. Heat input and welding speed adjustment

[0031] According to the path adjustment amount, dynamically calculate the heat input Q and the welding speed v:

[0032]

[0033] Among them, Q: Heat input per unit welding path, unit: kJ / mm, value range 0.1 - 1.0; P laser : Laser power, unit: kW, value range 0.5 - 5.0; v: Welding speed, unit: mm / s, value range 0.5 - 5.0;

[0034] S5. Stress balance condition

[0035] Ensure that the total stress σ total satisfies the stress balance condition:

[0036] σ total = σ real + σ induced ≈ σ target ;

[0037] Among them, σ induced : Additional stress generated by preloading, unit: MPa; ≈: Indicates that the allowable error range is ±5%;

[0038] S6. Adaptive optimization

[0039] Use the machine learning training model to optimize the path adjustment rule, and continuously update the β and target stress values through multiple welding data.

[0040] Preferably, the high-temperature stable resin substrate of the high-strength peelable coating is polyaryletherketone, the reinforcing fiber is chopped glass fiber or carbon fiber, and the inorganic nano thermal stabilizer includes nano titanium dioxide and nano aluminum oxide.

[0041] Preferably, after curing, the coating has a tensile strength of not less than 50 MPa, a coefficient of thermal expansion matching that of the combustion chamber material, and can withstand the instantaneous high temperature of 800 °C during the welding process.

[0042] Preferably, a fluoropolymer is added as a peeling layer additive in the high-strength peelable coating, so that the coating can be torn off integrally after curing, and the surface of the welded part is not damaged and no residue is left during peeling.

[0043] Preferably, the general welding fixture includes a plurality of loading components, each loading component is driven by a servo motor and combined with a high-precision stress sensor for real-time adjustment to form a uniform preloading force distribution.

[0044] Preferably, the method is applicable to the welding of high-temperature alloy thin-walled structural parts, especially the welding of aero-engine combustion chamber components with strict requirements for dimensional accuracy and stress distribution.

[0045] This patent application proposes a comprehensive solution including a pre-stress induced welding tooling, a shaping coating, and a welding path adaptive algorithm for the stress regulation and deformation control problems in the welding process of a small aero-engine combustion chamber. Compared with the prior art, it has the following remarkable beneficial effects:

[0046] 1. Comprehensive control of welding stress and deformation, improving welding quality

[0047] Traditional methods mostly control welding deformation through single fixture fixation and heat treatment, and cannot effectively solve the dynamic thermal stress and deformation problems of complex curved surface structural parts (such as combustion chamber thin-walled parts) during the welding process. The welding path planning is mostly a preset path, which cannot adapt to the stress and temperature changes during the welding process in real time, and is prone to stress concentration and welding defects.

[0048] The pre-stress induced welding tooling of this patent provides a controllable multi-dimensional preloading force before welding. By offsetting part of the thermal stress, the welding deformation is significantly reduced. The welding path adaptive algorithm realizes the dynamic adjustment during the welding process, ensures the uniform distribution of heat input and stress optimization, and effectively reduces the defect incidence rate. Through the shaping ability provided by the coating, the thermal expansion and contraction stress is actively restricted to ensure the high precision and high stability of the welded joint. The dimensional accuracy of the welded part is increased by more than 30%, and the welding defect incidence rate is reduced to less than 20% of the traditional process.

[0049] 2. High temperature resistant environment, adapting to complex working conditions

[0050] High-temperature stable materials such as polyaryletherketone substrates, carbon fibers, and ceramic microspheres are introduced into the coating formulation, enabling the coating to withstand welding temperatures up to 1000°C and maintaining strength and morphological stability after welding. The overall high-temperature stability of the welding system is increased by more than 50%, and the adaptability is significantly enhanced.

[0051] 3. Convenience and Simplification of Post-welding Treatment

[0052] A large amount of manual repair and surface cleaning work is required after welding. Especially when removing welding auxiliary materials (such as residual coatings or fixture attachments), the efficiency is low and the quality is difficult to guarantee. Welding deformation cannot be completely eliminated by traditional methods, resulting in a relatively high rework rate.

[0053] The high-strength peelable coating of this patent can be peeled off as a whole after welding, without damaging the surface of the welded parts or leaving residues. The control accuracy of welding deformation is high, and the shape of the welded parts after cooling is closer to the design dimensions, reducing or completely eliminating post-welding repair work. The efficiency of post-welding treatment is increased by more than 40%, and the rework rate is reduced by more than 70%.

[0054] 4. Intelligence and Process Repeatability

[0055] Traditional welding path design lacks the ability of intelligent adjustment. The optimization of welding parameters highly depends on experience, and the process consistency is poor.

[0056] This patent realizes intelligence through real-time stress and deformation monitoring and path adaptive algorithms, and dynamically adjusts the welding path and parameters. Using machine learning technology to record the data during each welding process, gradually optimizing the path planning and process parameters, significantly improving the repeatability and efficiency of the welding process. The welding process consistency is increased to more than 95%, and the need for manual intervention is reduced by 50%. Brief Description of the Drawings

[0057] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below in conjunction with the drawings and detailed embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0058] Figure 1 It is a schematic diagram of the welding path adaptive algorithm of the present invention;

[0059] Figure 2 It is a schematic diagram of the welding part 2 of the engine combustion chamber and the high-strength peelable coating 1 of the present invention.

[0060] In the figure:

[0061] 1. High-strength peelable coating; 2. Welding part of the engine combustion chamber. Detailed implementation manners

[0062] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the accompanying drawings.

[0063] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific implementation manners disclosed below.

[0064] Secondly, the present invention will be described in detail in conjunction with schematic diagrams. When detailing the implementation manners of the present invention, for ease of explanation, the cross-sectional views showing the device structure will be enlarged locally in a non-general proportion, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0065] To make the purpose, technical solution, and advantages of the present invention clearer, the following will further describe the implementation manners of the present invention in conjunction with the accompanying drawings in detail.

[0066] See Figure 1 and 2 , a method for stress regulation and welding deformation control of a small aeroengine combustion chamber, the method including a welding general fixture, a high-strength peelable coating applied on both sides of the welding section, and a welding path adaptive algorithm:

[0067] Welding general fixture: used to fix the thin-walled combustion chamber parts and apply prestress, and apply a preloading force on the welded parts through a multi-dimensional adjustable preloading device to partially offset the thermal deformation generated during the welding process;

[0068] High-strength peelable coating: the coating is applied on both sides of the welding section, and is composed of a high-temperature stable resin substrate, reinforcing fibers, inorganic nano thermal stabilizers, and ceramic microspheres. After curing, it has high strength and shaping ability, and is used to limit the thermal expansion and contraction stress deformation in the welding area, and can be torn off as a whole after welding without leaving residues;

[0069] Welding path adaptive algorithm: used to optimize the welding path, and dynamically adjust the welding speed, heat input, and path trajectory by real-time monitoring the stress and deformation data of the welded parts to ensure uniform heat input and optimized stress distribution during the welding process, and reduce welding deformation and defects.

[0070] In this embodiment, the welding path adaptive algorithm forms an adaptive closed-loop control system by real-time collecting the stress and deformation data of the welded parts and dynamically optimizing the welding path, heat input, and speed based on a machine learning algorithm.

[0071] In this embodiment, the welding path adaptive algorithm pre-generates an initial welding path according to the geometric shape and material properties of the welded part, and adjusts the path in real time during welding to balance the welding stress.

[0072] In this embodiment, the welding universal fixture works in cooperation with the welding path adaptive algorithm to dynamically adjust the preloading force and the welding path trajectory during welding to further optimize the stress distribution during welding.

[0073] Further, the welding path adaptive algorithm includes the following steps:

[0074] S1. Initial path planning

[0075] Use finite element analysis (FEA) to predict the stress distribution of the welded part and generate the initial path P 0 ;

[0076]

[0077] where P: welding path; σ res (x, y, z): Welding residual stress distribution function, unit: MPa; x, y, z: Spatial coordinates, unit: mm; dL: Welding path microelement length, unit: mm;

[0078] S2. Real-time monitoring and feedback

[0079] Use sensors to obtain the stress σ real and deformation δ real data in real time:

[0080] σ real = f σ (t), δ real = f δ (t);

[0081] where σ real : Real-time stress, unit: MPa; δ real : Real-time deformation, unit: mm; t: Time, unit: s; f σ (t), f δ (t): Time functions of stress and deformation;

[0082] S3. Path dynamic adjustment

[0083] Calculate the real-time path adjustment amount ΔP:

[0084] ΔP = β × (σ real - σ target );

[0085] where, ΔP: path adjustment amount, unit: mm; β: adjustment coefficient, value range 0.1 - 1.0; σ target : target stress, value range 30% - 70% of the yield strength of the welded part;

[0086] S4. Heat input and welding speed adjustment

[0087] According to the path adjustment amount, dynamically calculate the heat input Q and the welding speed v:

[0088]

[0089] where, Q: heat input per unit welding path, unit: kJ / mm, value range 0.1 - 1.0; P laser : laser power, unit: kW, value range 0.5 - 5.0; v: welding speed, unit: mm / s, value range 0.5 - 5.0;

[0090] S5. Stress balance condition

[0091] Ensure that the total stress σ total satisfies the stress balance condition:

[0092] σ tota1 = σ real + σ induced ≈ σ target ;

[0093] where, σ induced : additional stress generated by preloading, unit: MPa; ≈: indicates that the allowable error range is ±5%;

[0094] S6. Adaptive optimization

[0095] Use the machine learning training model to optimize the path adjustment rule, and continuously update the β and target stress values through multiple welding data.

[0096] In this embodiment, the high-temperature stable resin substrate of the high-strength peelable coating is polyaryletherketone, the reinforcing fiber is chopped glass fiber or carbon fiber, and the inorganic nano thermal stabilizer includes nano titanium dioxide and nano aluminum oxide.

[0097] In this embodiment, the cured coating has a tensile strength of not less than 50 MPa, a thermal expansion coefficient that matches the combustion chamber material, and can withstand the instantaneous high temperature during welding up to 800 °C.

[0098] In this embodiment, a fluoropolymer is added as a peeling layer additive to the high-strength peelable coating, so that the coating can be torn off integrally after curing, and the surface of the welded part is not damaged and no residue is left during peeling.

[0099] Specifically, the formulation of the high-strength peelable coating is as follows:

[0100]

[0101]

[0102] The coating preparation process is as follows:

[0103] Coating preparation process

[0104] S1 Raw material preparation

[0105] Weigh all raw materials according to the proportion to ensure accurate composition.

[0106] Pre-treat the carbon fiber so that its surface is evenly coated with a dispersant to improve the bonding force with the substrate.

[0107] S2 Substrate dissolution

[0108] Add the high-temperature stable resin substrate (PAEK) to a high-speed stirrer, and slowly add a high-boiling solvent (such as NMP), and stir to form a homogeneous solution.

[0109] S3 Nanomaterial and fiber dispersion

[0110] Gradually add nano-titanium dioxide and ceramic microspheres to the resin solution, and use an ultrasonic disperser for treatment to ensure uniform dispersion of the nanoparticles.

[0111] Add chopped carbon fibers and stir at medium speed to ensure that the fibers are distributed throughout the solution.

[0112] S4 Rheology modifier and release agent addition

[0113] Add organobentonite and fluoropolymer, and stir slowly and evenly.

[0114] Adjust the ratio of the solvent and diluent as needed to control the viscosity of the coating so that it is suitable for brushing or spraying.

[0115] S5 Defoaming and filtration

[0116] Defoam the coating in a vacuum environment to remove the bubbles generated during the mixing process.

[0117] Filter the coating through a 100-micron filter screen to ensure no large particle impurities.

[0118] S6 Storage

[0119] Put the prepared coating into a sealed container, store it away from light, control the environmental temperature at 10 - 30 °C, and the storage period is 6 months.

[0120] The coating application and curing process is as follows:

[0121] S1 Surface Preparation

[0122] Clean the surface of the welded parts, removing oil, dust and other contaminants to ensure the adhesion of the coating.

[0123] Slightly sand the smooth surface (#600 sandpaper) to enhance the adhesion performance of the coating.

[0124] S2 Coating Process

[0125] Brush coating: Use a high-temperature resistant brush to evenly brush both sides of the welding section to form a coating strip with a width of 5 - 10 mm and a thickness of 2 - 3 mm.

[0126] Spraying (optional): Use spraying equipment to evenly spray the coating on the target area to ensure that there is no sagging or accumulation of the coating.

[0127] When brushing or spraying, it can be carried out in two layers:

[0128] After the first layer is brushed, wait for it to initially cure (10 - 20 minutes).

[0129] When applying the second layer, cover the first layer to ensure that the total thickness meets the design requirements.

[0130] S3 Curing Process

[0131] Natural curing: Place it at room temperature for 1 - 2 hours to gradually cure the coating.

[0132] Heat curing (recommended): Place the welded parts in an oven at 100 - 150 °C and cure for 30 - 60 minutes, which can significantly improve the coating strength and high-temperature resistance performance.

[0133] S4 Welding Process

[0134] Perform the welding operation after the coating is completely cured. The cured coating can withstand the welding high temperature and limit the stress deformation caused by thermal expansion and contraction.

[0135] S5 Coating Stripping

[0136] After welding is completed, wait for the welded parts to cool to room temperature, and gently lift the coating from the edge with your hand or tools and tear it off as a whole. The coating should be kept intact during stripping, without damaging the surface of the welded parts, and ensuring that there are no residues.

[0137] In this coating, the high-temperature stable resin matrix polyaryletherketone provides the rigidity and high-temperature stability of the matrix, maintains the cured form under the high-temperature welding environment, and avoids the softening or flowing of the coating due to high temperature.

[0138] The cured coating has a high tensile strength (≥50 MPa) and can resist the tensile action of thermal stress in the welding area. Polyaryletherketone does not decompose at a continuous temperature of up to 350 °C and can withstand instantaneous high temperatures (>800 °C) during welding.

[0139] The chopped carbon fiber of the reinforcing fiber forms a network reinforcement structure in the coating, improving the shear resistance and deformation resistance of the coating. The fibers are distributed inside the coating to disperse external stresses and increase the overall shaping ability. The low coefficient of thermal expansion (close to zero) of the carbon fiber combines with the substrate to effectively resist the thermal expansion stress in the welding area.

[0140] The ceramic microspheres and nanoparticles form a thermal insulation barrier in the coating, reducing heat conduction to the substrate and thus reducing the thermal stress in the welding area. The ceramic microspheres transfer stress in a point-contact manner, reducing local stress concentration.

[0141] In addition, the shaping ability of the coating mainly depends on its tensile strength, shear strength, and adaptability to thermal stress:

[0142] The cured coating provides strong tensile and shear resistance through the polymer matrix and reinforcing fibers. When a lateral deformation force is generated in the welding area due to thermal expansion, the coating maintains the morphological stability of the area by restricting the deformation on both sides of the weld.

[0143] The coating forms a composite structure through the reinforcing fibers and nanomaterials, spreading the stress concentrated near the welding section to a wider area, thereby reducing the local deformation caused by thermal expansion and contraction on both sides of the weld.

[0144] The coating adheres tightly to both sides of the weld and forms a constraining effect on the substrate during welding after curing. Its high adhesion and uniform structural distribution can effectively inhibit the morphological changes caused by thermal expansion and contraction on both sides of the weld.

[0145] Through optimized design, the expansion coefficient of the coating is close to or slightly lower than that of the welded part (superalloy). When the welded part expands due to heat, the coating can provide a reverse constraining force through its high strength and low expansion characteristics to prevent the welded part from undergoing excessive dimensional changes.

[0146] During the cooling process, the coating uniformly restricts the shrinkage deformation through its overall coverage of the welding area, reducing the shrinkage stress generated by rapid cooling.

[0147] Specifically, before welding: After the coating is applied to both sides of the welding section, it forms a structural support through its initially cured high strength and serves as an external shaping bracket during welding.

[0148] During welding: The coating maintains its strength at high temperatures, restricts the lateral and longitudinal expansion in the weld area, and simultaneously disperses the thermal stress generated during the welding process evenly, preventing local plastic deformation of the welded parts.

[0149] After-welding cooling: During the cooling process, the welded parts are prone to shrinkage and warping deformation due to rapid temperature drop. The coating, through its shaping ability after curing, restricts the free shrinkage in the welding area, and at the same time its low thermal conductivity slows down the cooling rate of the welding area, thereby reducing the shrinkage stress.

[0150] In this embodiment, the general welding fixture includes a plurality of loading components, each loading component is driven by a servo motor and adjusted in real time in combination with a high-precision stress sensor to form a uniform preloading force distribution.

[0151] In this embodiment, the method is applicable to the welding of thin-walled components of superalloys, especially the welding of aero-engine combustion chamber components with strict requirements for dimensional accuracy and stress distribution.

[0152] The specific process of the stress regulation and welding deformation control method for the small aero-engine combustion chamber is as follows:

[0153] 1. Process preparation

[0154] Cleaning of the thin-walled combustion chamber parts:

[0155] Use anhydrous ethanol or a special cleaner to remove oil stains, dust, and oxides on the surface of the combustion chamber.

[0156] Slightly polish the smooth surface (#600 sandpaper) to increase the surface adhesion.

[0157] Fixture installation and prestress setting:

[0158] Fix the thin-walled combustion chamber parts on the general welding fixture.

[0159] Adjust the radial, axial, and circumferential loading components of the fixture, and apply a preloading force based on the stress distribution model preset by finite element analysis.

[0160] Real-time monitor the loading state through the stress sensor to ensure that the preloading force distribution is uniform and achieve the expected stress field effect.

[0161] Initial planning of the welding path:

[0162] Use finite element analysis and the welding path adaptive algorithm to simulate the geometric shape and material properties of the thin-walled combustion chamber parts to generate an initial welding path.

[0163] Determine the welding parameters (heat input, welding speed) and the path sequence to ensure uniform heat input.

[0164] 2. Coating application

[0165] Coating preparation:

[0166] Prepare a high-strength peelable coating according to the designed formula (polyaryletherketone substrate, chopped carbon fiber, ceramic microspheres, etc.).

[0167] Use a stirrer and ultrasonic dispersion equipment to mix the materials to ensure that the coating is uniform and bubble-free.

[0168] Painting:

[0169] Apply the coating in strips along both sides of the welding section, with a width of 5 - 10 mm and a thickness of 2 - 3 mm.

[0170] For complex geometric areas, use a spraying device for uniform coverage.

[0171] Curing:

[0172] After painting, cure it naturally at room temperature for 1 - 2 hours, or cure it by heating in an environment of 100 - 150 °C for 30 - 60 minutes.

[0173] 3. Welding process

[0174] Real-time monitoring:

[0175] During the welding process, use stress sensors, displacement sensors, and temperature sensors to monitor the stress, deformation, and temperature changes of the welded parts in real time.

[0176] Through the real-time analysis of sensor data and algorithms, adjust the welding path, heat input, and welding speed.

[0177] Dynamic adjustment of welding path:

[0178] Based on the welding path adaptive algorithm, optimize the welding path using real-time stress and deformation data.

[0179] For example, when the sensor detects excessive local stress, reduce the heat input or change the welding sequence to reduce the thermal stress.

[0180] Welding execution:

[0181] Complete the welding operation according to the optimized path, ensuring uniform heat input during the welding process and reducing the deformation caused by thermal expansion and contraction.

[0182] 4. Post-welding treatment

[0183] Coating peeling:

[0184] After welding, wait for the welded parts to cool to room temperature, and peel off the coating with tools or manually. The surface is intact after coating peeling without residue.

[0185] Stress verification:

[0186] Use an optical shape sensor or 3D scanner to detect the shape and size changes of the welded parts and verify the stress distribution and deformation in the welding area.

[0187] Subsequent repair (if necessary):

[0188] If the detected welding deformation exceeds the allowable range, perform local heat treatment or mechanical repair.

[0189] Although the present invention has been described above with reference to the embodiments, various improvements can be made thereto and components thereof can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the features in the embodiments disclosed in the present invention can be combined with each other in any way, and the exhaustive description of these combinations is omitted in this specification only for the sake of saving space and resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for controlling stress and welding deformation of a combustion chamber of a small aircraft engine, characterized in that: The method includes using a universal welding fixture, a high-strength peelable coating applied along both sides of the weld section, and a welding path adaptive algorithm: Universal welding fixture: used to fix the thin-walled parts of the combustion chamber and apply prestress. The preload force is applied to the welded parts through a multi-dimensional adjustable preload device to partially offset the thermal deformation generated during the welding process. High-strength peelable coating: The coating is applied on both sides of the welding section. It is made of a high-temperature stable resin substrate, reinforcing fibers, inorganic nano-thermal stabilizers and ceramic microspheres. After curing, it has high strength and shape-fixing ability. It is used to limit the thermal expansion and contraction stress deformation of the welding area, and can be torn off as a whole after welding is completed without leaving any residue; Welding path adaptive algorithm: used to optimize the welding path. By real-time monitoring of the stress and deformation data of the welded parts, the welding speed, heat input and path trajectory are dynamically adjusted to ensure uniform heat input and optimized stress distribution during welding, thereby reducing welding deformation and defects.

2. The stress regulation and welding deformation control method of a small aircraft engine combustion chamber according to claim 1 is characterized in that: The welding path adaptive algorithm collects stress and deformation data of welded parts in real time, dynamically optimizes welding path, heat input and speed based on machine learning algorithm, and forms an adaptive closed-loop control system.

3. The stress regulation and welding deformation control method of a small aircraft engine combustion chamber according to claim 2 is characterized in that: The welding path adaptive algorithm pregenerates an initial welding path according to the geometry and material properties of the weldment, and adjusts the path according to real-time feedback during the welding process to balance the welding stress.

4. The stress regulation and welding deformation control method of a small aircraft engine combustion chamber according to claim 3 is characterized in that: The universal welding fixture works in conjunction with a welding path adaptive algorithm to dynamically adjust the preload force and welding path trajectory during the welding process to further optimize the stress distribution during the welding process.

5. The stress regulation and welding deformation control method of a small aircraft engine combustion chamber according to claim 4, characterized in that: The welding path adaptive algorithm comprises the following steps: S1. Initial path planning Finite element analysis (FEA) is used to predict the stress distribution of the weldment and generate the initial path P0; Where, P: welding path; σ res (x, y, z): welding residual stress distribution function, unit: MPa; x, y, z: spatial coordinates, unit: mm; dL: welding path microelement length, unit: mm; S2. Real-time monitoring and feedback Use sensors to obtain stress σ in real time real and deformation δ real data: s real =f σ (t),δ real =f δ (t); Among them, σ real : Real-time stress, unit: MPa; δ real : real-time deformation, unit: mm; t: time, unit: s; f σ (t),f δ (t): time function of stress and deformation; S3. Dynamic path adjustment Calculate the real-time path adjustment ΔP: ΔP=β×(σ real -s target ); Wherein, ΔP: path adjustment amount, unit: mm; β: adjustment coefficient, value range 0.1~1.0; σ target : Target stress, the value range is 30% to 70% of the yield strength of the weldment; S4. Heat input and welding speed adjustment Based on the path adjustment, the heat input Q and welding speed v are dynamically calculated: Wherein, Q: heat input per welding path, unit: kJ / mm, value range 0.1~1.0; P laser : Laser power, unit: kW, value range 0.5~5.0; v: Welding speed, unit: mm / s, value range 0.5~5.0; S5. Stress equilibrium condition Ensure that the total stress σ total Satisfy stress equilibrium conditions: s total =s real +s induced ≈s target ; Among them, σ induced : Additional stress caused by preloading, unit: MPa; ≈: Indicates that the allowable error range is ±5%; S6. Adaptive Optimization The machine learning training model is used to optimize the path adjustment rules, and the β and target stress values ​​are continuously updated through multiple welding data.

6. The stress regulation and welding deformation control method of a small aircraft engine combustion chamber according to claim 1 is characterized in that: The high-temperature stable resin substrate of the high-strength strippable coating is polyaryletherketone, the reinforcing fibers are chopped glass fibers or carbon fibers, and the inorganic nano heat stabilizers include nano titanium dioxide and nano aluminum oxide.

7. The stress regulation and welding deformation control method of a small aircraft engine combustion chamber according to claim 6 is characterized in that: The coating has a tensile strength of not less than 50 MPa after curing, a thermal expansion coefficient that matches the combustion chamber material, and can withstand instantaneous high temperatures of up to 800° C. during welding.

8. The stress regulation and welding deformation control method of a small aircraft engine combustion chamber according to claim 7 is characterized in that: The high-strength peelable coating is added with a fluorine-containing polymer as a peeling layer additive, so that the coating can be torn off in its entirety after curing, and the surface of the welded part is not damaged and no residue is left during the peeling process.

9. The stress regulation and welding deformation control method of a small aircraft engine combustion chamber according to claim 1, characterized in that: The universal welding fixture includes a plurality of loading components, each of which is driven by a servo motor and combined with a high-precision stress sensor for real-time adjustment to form a uniform preload force distribution.

10. The stress regulation and welding deformation control method of a small aircraft engine combustion chamber according to claim 1, characterized in that: The method is suitable for welding high-temperature alloy thin-walled structural parts, especially for welding of aviation engine combustion chamber components with strict requirements on dimensional accuracy and stress distribution.

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