Laser shock forming finite element simulation method and device based on equivalent internal bending moment
By converting the stress gradient distribution field into an equivalent internal bending moment in laser shock forming simulation, establishing a shell element finite element model and performing static solutions, the problems of high cost and low efficiency in laser shock forming simulation are solved, achieving efficient and accurate simulation results. This method is suitable for forming simulation under complex boundary conditions and multiple impact processes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-04-03
AI Technical Summary
Existing laser shock forming simulation technology suffers from high simulation costs and low efficiency, failing to meet the requirements for synchronous simulation during actual processing.
The impact craters and stress gradient distribution field on the surface of the part were obtained by single-point laser shock test, which were then converted into equivalent internal bending moments. A shell element finite element model was established based on the actual material parameters of the part, and equivalent internal bending moments and constraints were applied. The mesh was generated by mapping method, and static solutions were performed to obtain the deformation state of the part after multiple impacts.
It significantly improves the computational efficiency and convergence of the laser forming simulation process, is suitable for forming simulation under complex boundary conditions and multiple impact processes, accurately predicts the deformation trend of medium and thick plates after forming, improves the prediction accuracy of laser shock forming, and meets the synchronous simulation requirements in actual processing.
Smart Images
Figure CN121787150A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of laser shock forming simulation technology, and in particular to a finite element simulation method and apparatus for laser shock forming based on equivalent internal bending moment. Background Technology
[0002] Sheet metal forming technology enables the processing of sheet metal into specific shapes with functional applications, and it has wide applications in aerospace, automotive, and railway industries. Forming methods include laser shock forming, shot peening, roll forming, and thermoforming. Simulating the sheet metal forming process allows for advance verification of whether the part's process requirements are met, thereby reducing trial-and-error costs and ensuring production feasibility.
[0003] Currently, related technologies are hampered by high simulation costs and extremely low efficiency in the laser shock forming simulation process, failing to meet the synchronous simulation requirements of actual processing. There is an urgent need for a high-precision and high-efficiency laser shock forming simulation method. Summary of the Invention
[0004] In view of this, this application provides a finite element simulation method and apparatus for laser shock forming based on equivalent internal bending moment. The main purpose is to improve the technical problem in the laser shock forming simulation process, which is unable to meet the synchronous simulation requirements in the actual processing due to high simulation cost and low efficiency.
[0005] Firstly, this application provides a finite element simulation method for laser shock forming based on equivalent internal bending moment, the method comprising: The impact pits and stress gradient distribution field on the surface of the part were obtained by single-point laser shock testing. The stress gradient distribution field is equivalently converted into the equivalent internal bending moment corresponding to the edge of the impact crater. Based on the actual material parameters of the part, a shell element finite element model corresponding to the part is established. The equivalent stress and constraint conditions corresponding to the equivalent internal bending moment are applied to the shell element finite element model. The shell element finite element model is meshed using the mapping method. By performing static analysis on the shell element finite element model after applying equivalent internal bending moment and constraint conditions, the deformation state of the part after multiple impacts can be obtained.
[0006] Secondly, this application provides a finite element simulation device for laser shock forming based on equivalent internal bending moment, the device comprising: The acquisition module is configured to acquire the impact pits and stress gradient distribution field on the surface of the part through a single-point laser shock test; The conversion module is configured to convert the stress gradient distribution field into an equivalent internal bending moment corresponding to the edge of the impact crater. The acquisition module is configured to establish a shell element finite element model corresponding to the part based on the actual material parameters of the part, apply the equivalent stress and constraint conditions corresponding to the equivalent internal bending moment to the shell element finite element model, and perform mesh generation of the shell element finite element model using the mapping method; and obtain the deformation state of the part after multiple impacts by performing static solution on the shell element finite element model after applying the equivalent internal bending moment and constraint conditions.
[0007] Thirdly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method of the first aspect.
[0008] Fourthly, this application provides an electronic device, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor executes the computer program to implement the method of the first aspect.
[0009] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the method of the first aspect.
[0010] Using the above technical solution, this application provides a finite element simulation method and apparatus for laser shock forming based on equivalent internal bending moment. Compared with current related technologies, this application obtains the impact pit and stress gradient distribution field on the surface of the part through a single-point laser shock test; the stress gradient distribution field is equivalently converted into the equivalent internal bending moment corresponding to the edge of the impact pit; a shell element finite element model corresponding to the part is established based on the actual material parameters of the part; equivalent stress and constraint conditions corresponding to the equivalent internal bending moment are applied to the shell element finite element model; the shell element finite element model is meshed using a mapping method; and the deformation state of the part after multiple impacts is obtained by performing static solution on the shell element finite element model after applying equivalent stress and constraint conditions. By applying the technical solution of this application, the measured stress gradient distribution field in a single-point laser shock test is transformed into an equivalent internal bending moment. Based on the actual material parameters of the part, a shell element finite element model corresponding to the part is established. The equivalent stress and constraint conditions corresponding to the equivalent internal bending moment are applied to the shell element finite element model. The shell element finite element model is meshed using a mapping method and combined with local adaptive mapping meshing technology. Finally, static solutions are performed to obtain the deformation state of the part after multiple impacts. This significantly improves the computational efficiency and convergence of the laser forming simulation process. It is suitable for forming simulation under complex boundary conditions and multiple impact processes. It can accurately predict the deformation trend after forming of medium and thick plates, effectively improve the prediction accuracy of laser shock forming. By replacing dynamics with static equivalence, the simulation efficiency of laser shock forming is greatly improved, providing a reliable theoretical basis for process optimization and meeting the synchronous simulation requirements in actual processing.
[0011] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description
[0012] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0014] Figure 1A flowchart illustrating a finite element simulation method for laser shock forming based on equivalent internal bending moment, provided in an embodiment of this application, is shown. Figure 2 This document shows an example of a laser shock forming finite element simulation flowchart provided in an embodiment of this application. Figure 3 This paper illustrates a schematic diagram of the equivalent internal bending moment of a stress gradient field, as provided in an embodiment of this application. Figure 4 This illustration shows a schematic diagram of an example laser shock specimen provided in an embodiment of this application; Figure 5 This paper shows an example of a laser shock forming finite element model diagram provided in an embodiment of this application; Figure 6 This paper presents a comparison chart of simulation test results for bending deformation of an example part provided in an embodiment of this application; Figure 7 A schematic diagram of a laser shock forming finite element simulation device based on equivalent internal bending moment, provided in an embodiment of this application, is shown. Detailed Implementation
[0015] To better understand the above-mentioned objectives, features, and advantages of this application, the solution of this application will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.
[0016] While related technologies address challenges such as high mold-making costs and severe springback cracking issues in the development stages of aviation, aerospace, and train manufacturing, as well as in small-batch, customized production, laser shock forming technology can effectively solve these problems. Furthermore, the proposed laser shock forming simulation method can effectively overcome the technical bottleneck of existing simulation technologies lagging significantly behind actual production applications in terms of efficiency.
[0017] To address the technical problem of high simulation costs and low efficiency in laser shock forming simulation, which fails to meet the requirements for simultaneous simulation during actual processing, this embodiment provides a finite element simulation method for laser shock forming based on equivalent internal bending moment. Figure 1 As shown, the method includes: Step 101: Obtain the impact pits and stress gradient distribution field on the surface of the part through a single-point laser shock test.
[0018] Among them, the laser process parameters of the single-point laser shock test may include, but are not limited to, laser energy, spot diameter, pulse width, sacrificial layer material and thickness, and constraint layer material and thickness; the parts may include, but are not limited to, metal plates and thin-walled structural parts, and the materials of the parts may include, but are not limited to, aluminum alloys, titanium alloys, and high-strength steel.
[0019] In some embodiments, an impact crater refers to a localized depression formed on the surface of a part after laser impact, and the stress gradient distribution field can be used to represent the stress variation law along the depth direction of the part's surface. During a single-point laser impact test, a sample made of the same material as the part is first prepared, fixed on the test bench, ensuring the impact area is flat, and the laser process parameters are set. The sample surface is then impacted at a single point, and the geometric parameters such as the diameter and depth of the impact crater are recorded after impact. An X-ray stress meter and a point-dissection delamination instrument are used to measure the stress values layer by layer along the depth direction of the crater center to obtain the stress gradient distribution field. Optionally, a single-row laser impact test can also be performed.
[0020] Step 102: Convert the stress gradient distribution field into an equivalent internal bending moment corresponding to the edge of the impact crater.
[0021] In some embodiments, the stress gradient distribution field is the stress variation along the depth direction of the surface layer of the part (high compressive stress on the surface and low stress in the deeper layers). This distribution causes a deformation difference between the surface and inner layers of the material, which can be equivalent to the internal moment that causes bending at the edge of the impact dent, i.e., the equivalent internal bending moment. Specifically, firstly, the stress gradient distribution field data can be extracted to obtain the stress value along the depth direction of the impact dent region. Then, the stress moment can be calculated by integrating the stress in the depth direction (stress × area moment) to obtain the resultant stress moment per unit length. Then, an equivalent transformation is performed to convert the stress moment into an internal bending moment concentrated at the edge of the dent according to the actual size (diameter, range) of the impact dent. This serves as the equivalent stress for subsequent simulations, thereby improving the computational efficiency and convergence of the laser forming simulation process. It is suitable for forming simulation under complex boundary conditions and multiple impact processes, and can accurately predict the deformation trend after forming of medium and thick plates, effectively improving the prediction accuracy of laser shock forming.
[0022] Step 103: Based on the actual material parameters of the part, establish the shell element finite element model corresponding to the part, and apply the equivalent stress and constraint conditions corresponding to the equivalent internal bending moment to the shell element finite element model.
[0023] In some embodiments, the shell element finite element model employs a mapping method for mesh generation. For example, firstly, the actual material parameters of the part, such as the elastic modulus, yield strength, and thickness of the aluminum alloy, can be obtained. Then, a self-developed finite element program is used to construct a shell element model of the same size as the part based on the actual material parameters. Mapping mesh generation is then performed, mapping the boundary shape of the geometric model onto the topology of a regular mesh. By strictly matching the distribution of boundary nodes, regularly shaped and orderly arranged elements (such as quadrilateral eight-node elements) are generated to ensure mesh quality and computational accuracy. For example, the impact region corresponding to the part can be divided into quadrilateral shell elements to ensure smooth mesh transition. Correspondingly, equivalent stress and constraints are applied to the shell element finite element model, such as converting the equivalent internal bending moment into the equivalent stress of the shell element edge nodes (allocated by shape function interpolation) to simulate impact driving; and applying fixed constraints (limiting displacement and rotation) to both ends of the plate to simulate actual clamping.
[0024] Step 104: By performing static solution on the shell element finite element model after applying equivalent internal bending moment and constraint conditions, the deformation state of the part after multiple impacts is obtained.
[0025] In some embodiments, in a self-compiled finite element program, equivalent internal bending moments can be applied sequentially at corresponding nodes according to the actual impact sequence (e.g., 200 impacts at 5mm intervals along the length of the plate). The plastic deformation of each impact is automatically accumulated. After obtaining the node deformation vector through static solution, the node coordinate matrix is updated to obtain the deformation state of the part after the current laser impact. Then, the position of the crater for the next laser impact can be updated, the mesh can be re-divided, and so on until all impact sequences are completed, the simulation process ends, and the deformation state of the part after multiple impacts is obtained to determine whether it meets the part design requirements. In this way, by using static equivalence to replace dynamics and performing cumulative calculations, the superimposed deformation of multiple impacts is efficiently simulated, which greatly improves the simulation efficiency of laser shock forming and provides a reliable theoretical basis for process optimization.
[0026] By applying the technical solution of this application, the measured stress gradient distribution field in a single-point laser shock test is transformed into an equivalent internal bending moment. Based on the actual material parameters of the part, a shell element finite element model corresponding to the part is established. The equivalent stress and constraint conditions corresponding to the equivalent internal bending moment are applied to the shell element finite element model. The shell element finite element model is meshed using the mapping method and combined with the local adaptive mapping meshing technology. Finally, static solution is performed to obtain the deformation state of the part after multiple impacts. This significantly improves the computational efficiency and convergence of the laser forming simulation process. It is suitable for forming simulation of complex boundary conditions and multiple impact processes. It can accurately predict the deformation trend after forming of medium and thick plates, effectively improve the prediction accuracy of laser shock forming. By replacing dynamics with static equivalence, the simulation efficiency of laser shock forming is greatly improved, providing a reliable theoretical basis for process optimization and meeting the synchronous simulation requirements in actual processing.
[0027] Furthermore, as a refinement and extension of the specific implementation of the above embodiments, in order to fully illustrate the implementation of this embodiment, step 102 may optionally include: based on the stress gradient distribution field, taking the neutral layer of the plate corresponding to the part as the depth direction coordinate 0 point, integrating the stress along the depth direction, and using the obtained integration result as the equivalent internal bending moment distributed along the edge of the impact pit; the stress gradient distribution field is formed by measuring the surface residual stress distribution of the part by X-ray diffraction after the single-point laser shock experiment, and then eroding the plate layer by layer by electrolytic peeling method to form stress gradient data along the depth direction.
[0028] In some embodiments, the plate is subjected to single-point or single-row laser shock. A dynamic simulation model of laser shock is established using actual material parameters and laser shock process parameters. The stress values along the depth direction near the edge of the laser shock pit are extracted as known conditions for the equivalent internal bending moment to be determined. Taking the neutral layer of the plate as the 0 point of the depth direction coordinate, the measured stress gradient is integrated along the depth direction to obtain the stress moment.
[0029] Optionally, the equivalent internal bending moment is obtained by integrating the measured stress along the thickness direction, and its calculation formula can be expressed as: ; in, σ This represents the residual stress distribution along the plate thickness direction. z These are the coordinates in the thickness direction. dA Let the area be a microelement. h This refers to the thickness of the sheet material.
[0030] Optionally, a shell element finite element model corresponding to the part is established based on the actual material parameters of the part, including: determining the element type and element thickness of the shell element finite element model according to the actual material parameters of the part. The element type includes 8-node Mindlin-Reissner shell element, and the element thickness is determined according to the actual material thickness in the actual material parameters.
[0031] For example, the shell element finite element model can use an 8-node element based on the Mindlin-Reissner shell element. Since the thickness of the shell element does not participate in the finite element mesh generation, the number of meshes can be greatly reduced, improving computational efficiency. Based on the mapping method, the mesh generation of the shell element finite element model is based on the following formula: ; In the formula C i ( i = 1 to 4) are the four boundaries of the region. E i ( i = 1 to 4) are the four corner points of the quadrilateral. ξ and η These are the normalized mapped coordinates in two directions, respectively. X and Y These are the coordinates of all mapped nodes within the region.
[0032] This adaptive meshing method employs parameterized mapping meshing rules and drives the mesh re-meshing process based on the laser impact position, achieving dynamic refinement of local areas. When the impact position changes, the coordinates of the crater center are automatically identified, and the influence domain is expanded using this point as a reference. A preset mapping template is then used to generate a high-quality quadrilateral element mesh.
[0033] Optionally, apply equivalent stress and constraints corresponding to the equivalent internal bending moment to the shell element finite element model, including: applying the equivalent internal bending moment to the nodes near the edge of the impact crater in the shell element finite element model in the form of shape function interpolation, where the shape function interpolation includes linear shape function interpolation and higher-order shape function interpolation, and the nodes include discrete nodes on the contour line of the simulated crater edge; and applying constraints to the shell element finite element model according to the actual working conditions corresponding to the single-point laser shock test, where the constraints include fixed constraints, displacement constraints, or elastic support constraints, and the position and type of the constraints are consistent with the clamping state during the actual machining of the part.
[0034] In some embodiments, a shell element finite element model can be established based on the actual material parameters of the part, and the part can be meshed based on the mapping principle. The mesh at the location of the current impact crater corresponding to the laser shock test in the shell element finite element model is refined, and the overall stiffness matrix is generated according to the element mesh logic.K and the quality matrix M The measured stress moment is multiplied by the area of application and applied to the finite element pit node using shape function interpolation to realize the external force of the shell element finite element model. F External constraints are applied to the corresponding positions in the shell element finite element model according to the clamping method in the actual forming process, and the overall stiffness matrix is updated. K This facilitates the statics solution. For example, the solution matrix equation for the statics solution of a finite element model can be expressed as: U = F / K ,in U It can represent the node deformation vector.
[0035] Optionally, step 104 may specifically include: using a self-compiled finite element model to perform static solution on the shell element finite element model after cumulative loading of equivalent internal bending moment, to obtain the deformation state of the part after multiple impacts, and the self-compiled finite element model is used to determine the deformation state of the part corresponding to multiple impacts.
[0036] Optionally, the equivalent internal bending moment can be cyclically applied to the shell element finite element model, and the deformation can be calculated cumulatively.
[0037] Among them, statics can be solved by analyzing a self-developed finite element model. The self-developed finite element model can be a custom-developed finite element program, which is used to automatically identify the spot position of each laser impact, dynamically adapt the mesh (refine the impact zone and coarse the non-impact zone), and balance the calculation efficiency and accuracy. Multiple impacts are achieved by cyclically loading the equivalent internal bending moment and accumulating the deformation.
[0038] In some embodiments, equivalent internal bending moments (each corresponding to a spot position) can be repeatedly applied to the shell element finite element model according to the actual impact sequence to simulate the cumulative effect of multiple laser impacts. Then, the deformation is calculated cumulatively. After each loading, the deformation of the part is recorded, and the deformation result is used as the initial state for the next loading. The total deformation is obtained by superimposing the results.
[0039] Specifically, a shell element base model can be generated in a self-compiled finite element model. Material parameters, the location of the initial impact spot, and the equivalent internal bending moment are input. The mesh is automatically refined at the spot location, and the equivalent internal bending moment and constraints are applied. Static calculations are performed, and the deformation after the first impact is recorded. This process is repeated for cyclic loading and cumulative deformation. The self-compiled model automatically adjusts the mesh in the area by updating the spot location. Using the previous deformation result as the initial state, the equivalent internal bending moment is applied, and the deformation is solved and accumulated. This process is repeated until a preset number of impacts (e.g., 200) is completed, and the final deformation state is output, thus completing the deformation prediction after multiple impacts. By dynamically adapting the spot location and mesh to the self-compiled model, the calculation accuracy of the impact zone is ensured while avoiding the inefficiency caused by an excessive overall mesh, achieving accurate and efficient simulation of multiple impacts.
[0040] As one possible implementation method, such as Figure 2 As shown in the figure, the laser shock forming finite element simulation method based on equivalent internal bending moment provided in this embodiment may specifically include the following steps: Step 1: Obtain the stress gradient distribution field, perform single-point or single-row laser shock on the plate, and extract the stress along the depth direction near the edge of the laser shock pit using an X-ray residual stress meter and an electrolytic stripping device as known conditions for the equivalent internal bending moment to be determined. Step 2: Equivalently transform the internal bending moment parameters. Taking the neutral layer of the plate as the zero point of the depth direction coordinate, integrate the measured stress gradient along the depth direction to obtain the stress moment. ; Step 3: Establish a shell element finite element model and mesh the part based on the mapping principle. Refine the mesh at the location of the current impact dent, and generate the overall stiffness matrix according to the element mesh logic. K and the quality matrix M ; Step 4: Apply the internal bending moment load, multiply the measured stress moment by the area of application, and apply it to the finite element pit node using shape function interpolation to realize the finite element external force. F The application; Step 5: Apply constraints. Apply external constraints to the corresponding positions in the finite element model according to the clamping method in the actual forming process, and update the overall stiffness matrix. K ; Step 6: Static solution of deformation state. Perform static solution on the finite element model, and the solution matrix equation is: U = F / K ; Obtain the node deformation vector U Then, updating the node coordinate matrix will give the deformation state of the part after the laser shock. Step 7: Update the position of the next laser impact crater, re-mesh, and repeat steps 3 to 6 until all impact sequences are completed, then end the simulation process.
[0041] Accordingly, taking a Q355 material sample as an example, a single-point laser shock test was first conducted on a 20mm×20mm×3mm sample. The laser energy was set to 15J, the pulse width to 15ns, the spot diameter to 4mm, and the wavelength to 1064nm. After the shock, the residual stress gradient data of the impact pit were obtained by X-ray diffraction and electrolytic stripping. The measured residual stress was integrated along the depth direction to obtain the equivalent torque value. ,like Figure 3 The diagram shows the original sample and the deformed sample, and the diagram of the deformation mechanism of the plate driven by the equivalent torque in laser shock forming. It shows the physical process from the local residual stress field to the macroscopic overall bending deformation. The dashed box can represent the original plate, the solid line can represent the plate after being impacted, and the stress gradient field can represent the non-uniform residual stress distribution generated in the laser shock area, which is the root cause of the bending moment.
[0042] Next, a 150mm×30mm×3mm sample can be subjected to laser shock. The laser shock parameters are set as follows: pulse energy 15J, pulse width 15ns, spot diameter 4mm, wavelength 1064nm. One end of the part is clamped, as shown in the image. Figure 4 The impact trajectory shown applies laser impacts to the specimen in three rows: row 1, row 2, and row 3. The distance from the clamping end to the starting point of the first laser impact can be set to 46 mm to obtain measured bending deformation data of the specimen in the length direction.
[0043] Furthermore, an equivalent internal bending moment shell element finite element model of the specimen can be established, such as... Figure 5 As shown. The equivalent torque is multiplied by the area of action and then applied to the corresponding nodes as an equivalent external force through shape function interpolation. The mesh accuracy of the pitted area is dynamically updated based on adaptive mapping mesh technology, and the static equations are solved in combination with the clamping boundary conditions to obtain the deformation morphology after each impact step. Finally, the deformations of each step are accumulated.
[0044] Correspondingly, the simulation results after laser shock with one, two, and three lines can be compared with the measured deformation profiles, such as... Figure 6As shown, the calculation error of the deformation amount is very small, verifying the effectiveness of the laser shock forming simulation method in predicting forming accuracy. The measured deformation data represents the actual deformation data of the specimen after laser shock obtained through physical experiments, which can be obtained using high-precision three-dimensional measuring equipment, such as a coordinate measuring machine or 3D scanner. Along the specimen length direction (x-axis), the scanned point cloud is fitted into a continuous z(x) curve. The simulation refers to the deformation result predicted by the shell element finite element model established using a self-developed finite element program.
[0045] Compared with related technologies, the embodiments of this application are based on the stress gradient distribution field. Taking the neutral layer of the plate corresponding to the part as the depth coordinate 0 point, the stress is integrated along the depth direction. The obtained integral result is used as the equivalent internal bending moment distributed along the edge of the impact crater. It is applied to the corresponding node as the equivalent external force through shape function interpolation. The mesh accuracy of the crater area is dynamically updated based on adaptive mapping mesh technology. Combined with the clamping boundary conditions, the static equation is solved to obtain the deformation mode after each impact. The shell element finite element model after the cumulative loading of the equivalent internal bending moment is statically solved using a self-developed finite element model to obtain the deformation state of the part after multiple impacts. The internal bending moment is used to equivalently replace the residual stress distribution, thereby reducing the non-uniform stress generated inside the material after laser impact. The field is transformed into an equivalent static load and applied to the finite element model. Through the equivalent transformation of stress gradient and internal bending moment and the loading of shape function interpolation, the model complexity of laser shock forming simulation is effectively simplified, and the simulation accuracy and computational efficiency are improved. It can efficiently and accurately simulate the deformation behavior of parts during multiple impacts, providing a reliable simulation basis for the optimization of laser shock forming process. It avoids the problems of high computational cost and convergence difficulty in traditional dynamic simulation, and effectively overcomes the problem of low forming prediction accuracy caused by the difficulty in accurately applying residual stress field. Combined with adaptive mapping mesh technology, the local mesh is dynamically reconstructed when the impact position changes each time, ensuring the geometric accuracy of the pit area and the solution resolution of the stress concentration area, and meeting the synchronous simulation requirements in the actual processing process.
[0046] Furthermore, embodiments of this application provide a finite element simulation device for laser shock forming based on equivalent internal bending moment, such as... Figure 7 As shown, the device includes: an acquisition module 31 and a conversion module 32.
[0047] The acquisition module 31 is configured to acquire the impact pits and stress gradient distribution field on the surface of the part through a single-point laser shock test. The conversion module 32 is configured to convert the stress gradient distribution field into an equivalent internal bending moment corresponding to the edge of the impact crater. The acquisition module 31 is configured to establish a shell element finite element model corresponding to the part based on the actual material parameters of the part, apply equivalent stress and constraint conditions corresponding to the equivalent internal bending moment to the shell element finite element model, and perform mesh generation of the shell element finite element model using the mapping method; by performing static solution on the shell element finite element model after applying the equivalent internal bending moment and constraint conditions, the deformation state of the part after multiple impacts is obtained.
[0048] In some embodiments, the conversion module 32 is specifically configured to integrate the stress along the depth direction based on the stress gradient distribution field, with the neutral layer of the plate corresponding to the part as the depth direction coordinate 0 point, and use the obtained integration result as the equivalent internal bending moment distributed along the edge of the impact pit; the stress gradient distribution field is formed by measuring the surface residual stress distribution of the part by X-ray diffraction after the single-point laser shock experiment, and then eroding the plate layer by layer by electrolytic peeling method to form stress gradient data along the depth direction.
[0049] In some embodiments, the acquisition module 31 is specifically configured to determine the element type and element thickness corresponding to the shell element finite element model based on the actual material parameters of the part. The element type includes an 8-node Mindlin-Reissner shell element, and the element thickness is determined based on the actual material thickness in the actual material parameters.
[0050] In some embodiments, the acquisition module 31 is specifically configured to apply the equivalent internal bending moment to the nodes near the edge of the impact crater in the shell element finite element model in the form of shape function interpolation. The shape function interpolation includes linear shape function interpolation and higher-order shape function interpolation. The nodes include discrete nodes on the contour line of the simulated crater edge. According to the actual working conditions corresponding to the single-point laser shock test, the shell element finite element model is subjected to constraint conditions. The constraint conditions include fixed constraints, displacement constraints or elastic support constraints. The position and type of the constraint conditions are consistent with the clamping state during the actual processing of the part.
[0051] In some embodiments, the acquisition module 31 is specifically configured to perform static solution on the shell element finite element model after cumulative loading of equivalent internal bending moment using a self-compiled finite element model, and obtain the deformation state of the part after multiple impacts. The self-compiled finite element model is used to determine the deformation state of the part corresponding to multiple impacts.
[0052] In some embodiments, the acquisition module 31 is specifically configured to acquire laser process parameters for single-point laser shock tests, including laser energy, spot diameter, pulse width, sacrificial layer material and thickness, and constraint layer material and thickness.
[0053] In some embodiments, the acquisition module 31 is specifically configured such that the parts include metal plates and thin-walled structural components, and the materials of the parts include aluminum alloys, titanium alloys, and high-strength steel.
[0054] It should be noted that other corresponding descriptions of the functional units involved in the laser shock forming finite element simulation device based on equivalent internal bending moment provided in this application embodiment can be found in the following references. Figure 1 The corresponding descriptions in [the document] will not be repeated here.
[0055] Based on the above, Figure 1 As illustrated in the example, correspondingly, embodiments of this application also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described... Figure 1 The example method shown.
[0056] Based on the above, Figure 1 As illustrated, correspondingly, embodiments of this application also provide a computer program product, including a computer program that, when executed by a processor, implements the above-described... Figure 1 The example method shown.
[0057] Based on this understanding, the technical solutions of the embodiments of this application can be embodied in the form of a software product. The software product can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, mobile hard drive, etc.) and includes several instructions to cause a computer device (such as a personal computer, server, or network device, etc.) to execute the methods of various implementation scenarios of this application.
[0058] Based on the above, Figure 1 The method shown, and Figure 7 To achieve the above objectives, the present application also provides an electronic device, comprising a storage medium and a processor; the storage medium for storing a computer program; and the processor for executing the computer program to implement the above-described virtual device embodiments. Figure 1 The method shown.
[0059] Optionally, the aforementioned electronic device may also include a user interface, a network interface, a camera, radio frequency (RF) circuitry, sensors, audio circuitry, a Wi-Fi module, etc. The user interface may include a display screen, an input unit, etc.
[0060] Those skilled in the art will understand that the physical device structure provided in this embodiment does not constitute a limitation on the physical device, and may include more or fewer components, or combine certain components, or have different component arrangements.
[0061] The storage medium may also include an operating system and a network communication module. The operating system is a program that manages the hardware and software resources of the aforementioned physical device, supporting the operation of information processing programs and other software and / or programs. The network communication module is used to enable communication between the various components within the storage medium, as well as communication with other hardware and software in the information processing physical device.
[0062] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platform, or it can be implemented by hardware. This application is based on the stress gradient distribution field, taking the neutral layer of the plate corresponding to the part as the depth direction coordinate 0 point, integrating the stress along the depth direction, and using the obtained integral result as the equivalent internal bending moment distributed along the edge of the impact crater. After multiplying the equivalent moment by the area of action, it is applied to the corresponding node as the equivalent external force through shape function interpolation. The mesh accuracy of the crater area is dynamically updated based on adaptive mapping mesh technology, and the static equation is solved in combination with the clamping boundary conditions to obtain the deformation mode after each impact. The shell element finite element model after the cumulative loading of the equivalent internal bending moment is statically solved using a self-compiled finite element model to obtain the deformation state of the part after multiple impacts. By using the internal bending moment to equivalently replace the residual stress distribution, the material after laser impact is... The non-uniform stress field generated internally is transformed into an equivalent static load and applied to the finite element model. Through the equivalent transformation of stress gradient and internal bending moment and the loading of shape function interpolation, the model complexity of laser shock forming simulation is effectively simplified, and the simulation accuracy and computational efficiency are improved. It can efficiently and accurately simulate the deformation behavior of parts during multiple impacts, providing a reliable simulation basis for the optimization of laser shock forming process. It avoids the problems of high computational cost and convergence difficulty in traditional dynamic simulation, and effectively overcomes the problem of low forming prediction accuracy caused by the difficulty in accurately applying residual stress field. Combined with adaptive mapping mesh technology, the local mesh is dynamically reconstructed when the impact position changes each time, ensuring the geometric accuracy of the pit area and the solution resolution of the stress concentration area.
[0063] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.
[0064] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to these embodiments, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A finite element simulation method for laser shock forming based on equivalent internal bending moment, characterized in that, include: The impact pits and stress gradient distribution field on the surface of the part were obtained by single-point laser shock testing. The stress gradient distribution field is equivalently converted into the equivalent internal bending moment corresponding to the edge of the impact crater. Based on the actual material parameters of the part, a shell element finite element model corresponding to the part is established. The equivalent stress and constraint conditions corresponding to the equivalent internal bending moment are applied to the shell element finite element model. The shell element finite element model is meshed using the mapping method. By performing static analysis on the shell element finite element model after applying equivalent internal bending moment and constraint conditions, the deformation state of the part after multiple impacts can be obtained.
2. The method according to claim 1, characterized in that, The step of converting the stress gradient distribution field into an equivalent internal bending moment corresponding to the edge of the impact crater includes: Based on the stress gradient distribution field, with the neutral layer of the plate corresponding to the part as the depth coordinate 0 point, the stress is integrated along the depth direction, and the obtained integration result is used as the equivalent internal bending moment distributed along the edge of the impact pit. The stress gradient distribution field is obtained by measuring the residual stress distribution on the surface of the part using X-ray diffraction after a single-point laser shock experiment, and then eroding the plate layer by layer using an electrolytic peeling method to form stress gradient data along the depth direction.
3. The method according to claim 1, characterized in that, The process of establishing a shell element finite element model of the part based on its actual material parameters includes: Based on the actual material parameters of the part, the element type and element thickness corresponding to the shell element finite element model are determined. The element type includes an 8-node Mindlin-Reissner shell element, and the element thickness is determined based on the actual material thickness in the actual material parameters.
4. The method according to claim 1, characterized in that, The application of the equivalent stress and constraint conditions corresponding to the equivalent internal bending moment to the shell element finite element model includes: The equivalent internal bending moment is applied to the nodes near the edge of the impact crater in the shell element finite element model in the form of shape function interpolation. The shape function interpolation includes linear shape function interpolation and higher-order shape function interpolation. The nodes include discrete nodes on the contour line of the simulated crater edge. According to the actual working conditions corresponding to the single-point laser shock test, constraints are applied to the shell element finite element model. The constraints include fixed constraints, displacement constraints, or elastic support constraints. The position and type of the constraints are consistent with the clamping state of the part during actual processing.
5. The method according to claim 1, characterized in that, The process involves statically solving the shell element finite element model after applying equivalent internal bending moments and constraints to obtain the deformation state of the part after multiple impacts, including: A self-developed finite element model is used to perform static solution on the shell element finite element model after cumulative loading of equivalent internal bending moment, so as to obtain the deformation state of the part after multiple impacts. The self-developed finite element model is used to determine the deformation state of the part corresponding to multiple impacts.
6. The method according to claim 1, characterized in that, The laser process parameters for the single-point laser shock test include laser energy, spot diameter, pulse width, sacrificial layer material and thickness, and constraint layer material and thickness.
7. The method according to claim 1, characterized in that, The parts include metal sheets and thin-walled structural components, and the materials of the parts include aluminum alloys, titanium alloys, and high-strength steel.
8. A finite element simulation device for laser shock forming based on equivalent internal bending moment, characterized in that, include: The acquisition module is configured to acquire the impact pits and stress gradient distribution field on the surface of the part through a single-point laser shock test; The conversion module is configured to convert the stress gradient distribution field into an equivalent internal bending moment corresponding to the edge of the impact crater. The acquisition module is configured to establish a shell element finite element model corresponding to the part based on the actual material parameters of the part, apply the equivalent stress and constraint conditions corresponding to the equivalent internal bending moment to the shell element finite element model, and perform mesh generation of the shell element finite element model using the mapping method; and obtain the deformation state of the part after multiple impacts by performing static solution on the shell element finite element model after applying the equivalent internal bending moment and constraint conditions.
9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 7.
10. An electronic device comprising a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 7.