Residual stress compensation analysis method and device for structural member

Abstract

The invention provides a structural member residual stress compensation analysis method and device. When the method is executed, simulation data of a structural part formed by stamping a simulation plate of stamping simulation software is obtained firstly, and the simulation data comprises a residual stress field stored in a shell unit node stress tensor form; mapping the residual stress field to a static strength grid of the structural member, and constructing a static strength model of the structural member; then correcting a stress-strain curve of the local material of the structural member based on the mapped residual stress value; and finally, based on the static strength model and the stress-strain curve of the local material of the structural member, in combination with the test working condition and the assembly constraint of the structural member, performing statics solution to obtain failure data, and based on the failure data, determining whether the structural member has a failure risk. In this way, the stress-strain curve of the local material of the structural member is corrected and adjusted based on the residual stress value, and failure analysis is conducted on the structural member more accurately.

Description

Technical Field

[0001] This application relates to the field of stamping technology, and in particular to a method and apparatus for residual stress compensation analysis of structural components. Background Technology

[0002] Existing structural components (such as automotive chassis components) are often formed by stamping, but the stamping process can lead to residual stress inside the material.

[0003] However, current stamping analysis ignores the residual internal stress generated during stamping, resulting in a large deviation between the analysis results and the actual failure modes. This necessitates multiple bench tests and manual corrections, leading to high trial-and-error costs. Summary of the Invention

[0004] In view of this, this application provides a method and apparatus for residual stress compensation analysis of structural components, aiming to solve the problems of large deviation between analysis results and actual failure modes and high research and development testing costs.

[0005] Firstly, this application provides a method for residual stress compensation analysis of structural components, including:

[0006] The simulation data of the stamping of sheet metal into structural parts is obtained by the stamping simulation software. The simulation data includes the residual stress field stored in the form of shell element nodal stress tensor.

[0007] The residual stress field is mapped onto the static strength mesh of the structural member to construct the static strength model of the structural member;

[0008] Based on the mapped residual stress value, the stress-strain curve of the local material of the structural component is corrected;

[0009] Based on the static strength model and the stress-strain curves of the local material of the structural component, combined with the test conditions and assembly constraints of the structural component, static analysis is performed to obtain failure data, and based on the failure data, it is determined whether the structural component has a failure risk.

[0010] Optionally, mapping the residual stress field to the static strength mesh of the structural member to construct the static strength model of the structural member includes:

[0011] An initial mesh is set for the structural component, and the initial mesh has the same mesh element type as the shell element corresponding to the residual stress field;

[0012] Based on the risk areas of the structural component, the initial mesh is locally refined to form the static strength mesh of the structural component. The risk areas include fillets and welds.

[0013] The residual stress field is mapped to multiple nodes of the static strength mesh of the structural member to obtain the static strength model.

[0014] Optionally, mapping the residual stress field to multiple nodes of the static strength mesh of the structural member includes:

[0015] The residual stress field is mapped to multiple nodes of the static strength grid of the structural member using a node mapping method and / or a field variable interpolation method.

[0016] Optionally, correcting the stress-strain curve of the local material of the structural component based on the mapped residual stress value includes:

[0017] For the elastic stage of the stress-strain curve, the original yield strength of the sheet is corrected based on the mapped residual stress value to determine the corrected yield strength of the elastic stage of the stress-strain curve. The larger the absolute value of the mapped residual stress value, the smaller the corrected yield strength.

[0018] For the plastic stage of the stress-strain curve, under the condition of residual tensile stress, the original saturation stress and hardening rate of the stress-strain curve in the plastic stage are corrected based on the mapped residual stress value. Under the condition of residual compressive stress, the original saturation stress and hardening rate of the stress-strain curve in the plastic stage are corrected based on the mapped residual stress value, thus obtaining the corrected saturation stress and hardening rate of the stress-strain curve in the plastic stage. The corrected saturation stress increases with increasing tensile stress and decreases with decreasing compressive stress, while the hardening rate decreases with increasing tensile stress and increases with decreasing compressive stress.

[0019] Optionally, the step of correcting the original yield strength of the sheet metal based on the mapped residual stress value to determine the corrected yield strength of the elastic stage of the stress-strain curve includes:

[0020] The corrected yield strength is obtained by subtracting the product of the mapped residual stress value and the correction factor from the original yield strength.

[0021] Optionally, the formula for calculating the corrected saturation stress is:

[0022]

[0023] Where Q0 is the saturation stress value of the plate when there is no residual stress, α is the first preset coefficient, and σ y0 σ represents the original yield strength of the plate material. r The mapped residual stress value is σ. r When the stress is tensile, it takes a positive value, σ r When the stress is compressive, the value is negative;

[0024] The formula for calculating the hardening rate is:

[0025]

[0026] Where b0 is the hardening rate of the plate when there is no residual stress, and β is the second preset coefficient.

[0027] Optionally, the test condition is an extreme condition. Based on the static strength model and the stress-strain curves of the local material of the structural component, combined with the test condition and assembly constraints of the structural component, static solutions are performed to obtain failure data, including:

[0028] Based on the ultimate working conditions of the structural component and the assembly constraints during installation, the equivalent plastic strain distribution of the structural component is determined according to the static strength model, the corrected saturation stress in the plastic stage of the stress-strain curve of the local material of the structural component, and the hardening rate.

[0029] The process of determining whether the structural component has a failure risk based on the failure data includes:

[0030] Determine whether there is a first region in the structural component where the equivalent plastic strain is greater than or equal to a preset value. If so, the first region is a failure risk region, and the structural component is at risk of failure.

[0031] Optionally, the test condition is a typical condition. Based on the static strength model and the stress-strain curve of the local material of the structural component, combined with the test condition and assembly constraints of the structural component, static solutions are performed to obtain failure data, including:

[0032] Based on the typical working conditions of the structural component and the assembly constraints during installation, the VonMises stress cloud diagram and safety factor of the structural component are determined based on the static strength model and the modified yield strength of the elastic stage of the stress-strain curve of the local material of the structural component.

[0033] The process of determining whether the structural component has a failure risk based on the failure data includes:

[0034] Determine whether there is a second region in the structural component where the Von Mises stress is greater than or equal to the ratio of the modified yield strength to the safety factor. If so, the second region is a failure risk region, and the structural component is at risk of failure.

[0035] Optionally, the method further includes:

[0036] Adjust the structure of the area where the structural component has a failure risk, replace the material of the structural component, and adjust any one or more of the stamping parameters, and then re-execute the simulation data of the stamping simulation software to simulate the stamping of the sheet metal to form the structural component and the subsequent steps.

[0037] Secondly, this application provides a structural component residual stress compensation analysis device, comprising:

[0038] The acquisition unit is used to acquire simulation data of the stamping simulation software to simulate the stamping of sheet metal into structural parts. The simulation data includes the residual stress field stored in the form of shell element nodal stress tensor.

[0039] A building block is used to map the residual stress field to the static strength mesh of the structural member, thereby constructing the static strength model of the structural member.

[0040] The correction unit is used to correct the stress-strain curve of the local material of the structural component based on the mapped residual stress value.

[0041] The analysis unit is used to perform static solutions based on the static strength model and the stress-strain curves of the local material of the structural component, combined with the test conditions and assembly constraints of the structural component, to obtain failure data, and to determine whether the structural component has a failure risk based on the failure data.

[0042] Thirdly, this application provides an apparatus comprising a memory and a processor, the memory for storing instructions or code, and the processor for executing the instructions or code to cause the apparatus to perform a structural residual stress compensation analysis method as described in any of the first aspects above.

[0043] Fourthly, this application provides a computer storage medium storing code, wherein when the code is executed, a device running the code implements a structural component residual stress compensation analysis method as described in any of the first aspects above.

[0044] This application provides a method and apparatus for residual stress compensation analysis of structural components. When executing the method, firstly, simulation data of sheet metal being stamped into a structural component is acquired using stamping simulation software. This simulation data includes a residual stress field stored in the form of shell element nodal stress tensors. Then, the residual stress field is mapped onto the static strength mesh of the structural component to construct a static strength model. Next, based on the mapped residual stress values, the stress-strain curves of the local material of the structural component are corrected. Finally, based on the static strength model and the stress-strain curves of the local material of the structural component, combined with the test conditions and assembly constraints of the structural component, static solutions are performed to obtain failure data. Based on the failure data, it is determined whether the structural component has a failure risk. The residual stress field of the structural component is extracted based on the stamping simulation. Then, the residual stress of the shell element in the stamping simulation is transferred to the shell element model for static strength analysis to obtain the static strength model. Subsequently, based on the direction and amplitude of the residual stress in the structural component, the stress-strain curve of the local material of the structural component is dynamically corrected and adjusted to make the stress-strain curve of the local material of the structural component closer to the actual situation. This is also beneficial to reflecting the influence of the forming and processing history of the sheet metal on the material properties. This ensures that subsequent static strength analysis is performed based on the modified static strength model under loading test conditions and actual assembly constraints, thereby improving the accuracy of predicting the failure risk area and enabling more reliable failure analysis of the structural component. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in this embodiment or the prior art, the drawings used in the description of the embodiment or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A flowchart illustrating a method for residual stress compensation analysis of structural components provided in this application embodiment;

[0047] Figure 2 This is a schematic diagram of a structural residual stress compensation analysis device for structural components provided in an embodiment of this application. Detailed Implementation

[0048] Currently, before stamping structural components, stamping simulation is performed. However, because the impact of residual stamping stress (some tensile or compressive stresses can reach 20%-30% of the material's yield strength) on material properties is not considered, and the correlation between stamping process parameters and static strength analysis is not established, it is impossible to quantify the distribution of residual stress. The local yield strength of the material is difficult to quantify and correct, which leads to prediction deviations in high-stress areas, resulting in redundancy and deficiencies in the structural design of some areas, increasing R&D costs and safety risks.

[0049] Therefore, this application provides a method and apparatus for residual stress compensation analysis of structural components. The residual stress field of the structural component is obtained through stamping simulation, and mapped onto each node of the static strength mesh. The residual stress of the shell element in the stamping simulation is transferred to the shell element model in the static strength analysis to obtain the static strength model. Then, based on the residual stress value of the structural component, i.e., according to the direction and value of the residual stress at each node on the structural component, the stress-strain curve of the local material of the structural component is dynamically adjusted. This allows the stress-strain range of the local material on the structural component to be adjusted according to the actual stamping process, realizing the combined analysis of stamping process simulation and structural strength. This facilitates the coupling of stamping process simulation and structural static strength analysis, enabling the quantification of the yield strength of the local material of the structural component. It reduces prediction deviations in high-stress and other risk areas, preventing redundancy or inadequacy in the structural design of local areas of the structural component. It also helps reduce the number of bench tests, saving R&D costs and safety risks.

[0050] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0051] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0052] Unless otherwise stated, the term "multiple" means two or more.

[0053] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0054] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0055] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0056] See Figure 1 , Figure 1 A flowchart illustrating a residual stress compensation analysis method for structural components provided in this application embodiment includes:

[0057] S101. Obtain simulation data of the stamping simulation software to simulate the stamping of sheet metal to form structural parts, wherein the simulation data includes residual stress fields stored in the form of shell element nodal stress tensors.

[0058] The aforementioned structural components are parts with a certain structure and shape formed by stamping sheet metal using a stamping process, such as subframes and torsion beams in vehicle chassis components.

[0059] Stamping is a pressure processing method that uses stamping dies to apply pressure to sheet metal on a press, causing it to undergo plastic deformation or separation to obtain parts of the desired shape and size. Stamping simulation software can be used to simulate the stamping process of sheet metal, obtaining relevant simulation data (such as three-dimensional displacement distribution, thickness change rate data, and stress distribution cloud maps at various stages of stamping) based on preset stamping parameters.

[0060] The stamping parameters in the above stamping simulation may include die geometry parameters, material model parameters, and friction coefficient (e.g., 0.1-0.15). The die geometry parameters may include surface clearance (e.g., 1-1.5 mm) and blank holder force (e.g., 80-15 KN). The material model parameters may include stress-strain curves (e.g., stress-strain curves of DP780 steel).

[0061] The residual stress in stamping is the internal residual stress caused by uneven plastic deformation during the cold stamping process of metal sheets.

[0062] Optionally, the areas of focus in this residual stress field may include the flange edge (tensile stress concentration) and the rounded corner area (compressive stress concentration).

[0063] Optionally, this area of ​​focus can be captured using a high-density shell cell mesh (e.g., 1 mm cell size) to capture details of local plastic deformation.

[0064] S102. Map the residual stress field to the static strength mesh of the structural component to construct the static strength model of the structural component.

[0065] In step S101 above, the residual stress field data is obtained by simulation and stored in the form of shell element nodal stress tensors. In step S102, the residual stress of the stamping simulation shell element is mapped and transferred to the static strength mesh to obtain the static strength model for static strength analysis.

[0066] S103. Based on the mapped residual stress value, correct the stress-strain curve of the local material of the structural component.

[0067] Optionally, the stress-strain curve of the local material of the structural component is corrected based on the residual stress values ​​mapped from each grid node in the static strength grid of the static strength model. This local material stress-strain curve is corrected by the residual stress values ​​of the corresponding grid nodes, achieving a quantitative correction of the local yield strength of the material, reducing prediction bias in high-stress areas, and improving the accuracy of subsequent failure risk prediction.

[0068] S104. Based on the static strength model and the stress-strain curve of the local material of the structural component, combined with the test conditions and assembly constraints of the structural component, static analysis is performed to obtain failure data, and the failure data is used to determine whether the structural component has a failure risk.

[0069] Optionally, the above test conditions can be divided into typical conditions and extreme conditions, so as to analyze the structural components under normal operation under typical conditions, and also to analyze abnormal extreme conditions.

[0070] The assembly constraints mentioned above are the actual constraints after the structural components are installed. For example, the assembly constraints of a vehicle's fender are the constraints corresponding to the installation relationship between the fender and the vehicle.

[0071] The above static analysis can be performed using finite element analysis software to obtain relevant parameters of stress and strain of the structural components and assess whether there is a risk of failure.

[0072] Based on the above steps S101-S104, this application obtains the residual stress distribution of the structural component through stamping simulation to extract the residual stress field of the structural component; then, based on the residual stress values ​​on the structural component obtained from the simulation, it maps the residual stress of the stamping simulation shell element to the static strength analysis shell element model; furthermore, based on the residual stress values ​​corresponding to each node of the structural component, it dynamically corrects and adjusts the stress-strain curve of the local material of the structural component, which is beneficial to reflecting the influence of the forming and processing history of the sheet metal on the material properties, so that subsequent static analysis can be performed based on working conditions and assembly constraints, and failure analysis of the structural component can be performed more accurately.

[0073] In the embodiments of this application, the above Figure 1 There are several possible implementations of step S102, which will be described below. It should be noted that the implementations given below are merely illustrative examples and do not represent all implementations of the embodiments of this application.

[0074] In step S102 above, mapping the residual stress field to the static strength mesh of the structural member to construct the static strength model of the structural member may include:

[0075] First, an initial mesh is set for the structural component, and the initial mesh has the same mesh element type as the shell element (stamping simulation mesh) corresponding to the residual stress field.

[0076] The above-mentioned grid cell types can include various types such as square grids and triangular grids.

[0077] The above-mentioned stamping simulation mesh (high-density shell element) and static strength mesh (medium-density shell element) use the same element type, but have different densities.

[0078] Secondly, based on the risk areas of the structural component, the initial mesh is locally refined to form the static strength mesh of the structural component. The risk areas include fillets and welds.

[0079] Optionally, local mesh refinement (element size ≤ 2mm) can be performed on high-risk areas (such as fillets and welds) in the static strength model.

[0080] Then, the residual stress field is mapped to multiple nodes of the static strength mesh of the structural member to obtain the static strength model.

[0081] Optionally, the above mapping error requirement can be that the stress transfer error in the critical area is ≤5%.

[0082] Optionally, the above mapping can employ methods such as nodal mapping or field variable interpolation. Nodal projection is suitable for meshes with consistent topology (e.g., the same mesh type), directly transferring nodal stress through coordinate matching. Field variable interpolation is suitable for cases with significant differences in mesh density, using shape function interpolation to achieve stress transfer at integration points. Thus, by using nodal projection or field variable interpolation, the stress transfer problem between shell elements of different densities can be solved, transferring the residual stress of the stamping simulation shell element to the static strength analysis shell element model (each mesh node of the static strength mesh), achieving high-precision mapping of short components and improving the accuracy of subsequent analysis.

[0083] In the embodiments of this application, the above Figure 1There are several possible implementations of step S103, which will be described below. It should be noted that the implementations given below are merely illustrative examples and do not represent all implementations of the embodiments of this application.

[0084] In step S103 above, correcting the stress-strain curve of the local material of the structural component based on the mapped residual stress value may include:

[0085] For the elastic stage of the stress-strain curve, the original yield strength of the sheet is corrected based on the mapped residual stress value to determine the corrected yield strength of the elastic stage of the stress-strain curve. The larger the absolute value of the mapped residual stress value, the smaller the corrected yield strength.

[0086] For the elastic stage of the stress-strain curve, the yield strength of the local material corresponding to each node is corrected based on the residual stress value of each node.

[0087] For the plastic stage of the stress-strain curve, under the condition of residual tensile stress, the original saturation stress and hardening rate of the stress-strain curve in the plastic stage are corrected based on the mapped residual stress value. Under the condition of residual compressive stress, the original saturation stress and hardening rate of the stress-strain curve in the plastic stage are corrected based on the mapped residual stress value, thus obtaining the corrected saturation stress and hardening rate of the stress-strain curve in the plastic stage. The corrected saturation stress increases with increasing tensile stress and decreases with decreasing compressive stress, while the hardening rate decreases with increasing tensile stress and increases with decreasing compressive stress.

[0088] The stress-strain curves described above are curves that describe the relationship between stress and strain in a material during uniaxial tension or compression, and are divided into elastic stage and plastic stage.

[0089] In the elastic stage, stress is proportional to strain and follows Hooke's Law; in the plastic stage, the material undergoes irreversible deformation, and stress changes nonlinearly with strain, which needs to be described by the hardening curve.

[0090] The aforementioned hardening curves describe the change in flow stress with equivalent plastic strain during the plastic deformation stage of a material, reflecting the work hardening characteristics of the material. The aforementioned equivalent plastic strain describes the accumulated irreversible strain during the plastic deformation stage, characterizing the degree of localized plastic deformation in the material.

[0091] By correcting the yield strength of local materials in structural components (elastic stage) and adjusting the hardening curve (plastic stage) using residual stress values, the influence of sheet metal forming history on material properties can be reflected. This achieves a residual stress compensation mechanism that couples stamping process simulation with structural static strength analysis, thereby improving the prediction accuracy of failure areas.

[0092] In one possible implementation, the original yield strength of the sheet metal is corrected based on the mapped residual stress value to determine the corrected yield strength of the elastic stage of the stress-strain curve, including:

[0093] The corrected yield strength is obtained by subtracting the product of the mapped residual stress value and the correction factor from the original yield strength.

[0094] Therefore, the specific formula for correcting the yield strength of the elastic stage of the local material stress-strain curve using residual stress values ​​can be:

[0095] σ y ′=σ y0 -k·|σ r |

[0096] Where, σ y0 σ is the original yield strength of the material (e.g., 780 MPa for DP780 steel); k is a correction factor (0.5-0.8, which can be calibrated by uniaxial tensile testing); σ r The mapped residual stress value is σ. r When the stress is tensile, it takes a positive value, σ r The value is negative when it is compressive stress.

[0097] In one possible implementation, the hardening curve of the local material of the structural component is adjusted based on the mapped residual stress value to correct the original saturation stress and hardening rate of the local material of the structural component.

[0098] The formula for calculating the corrected saturation stress is as follows:

[0099]

[0100] Wherein, Q0 is the saturation stress value of the plate when there is no residual stress;

[0101] α is the first preset coefficient, and the value of α can be 0.2-0.5, which can be determined by combining uniaxial tensile test with residual stress measurement;

[0102] σ y0 The original yield strength of the plate material;

[0103] σ r The mapped residual stress value is σ. r When the stress is tensile, it takes a positive value, σ r When the stress is compressive, the value is negative;

[0104] The formula for calculating the hardening rate is:

[0105]

[0106] Wherein, b0 is the hardening rate of the plate when there is no residual stress;

[0107] β is a second preset coefficient, which can be 0.1-0.3 and can be determined by combining uniaxial tensile test with residual stress measurement.

[0108] Understandably, for tensile residual stress, an increase in saturation stress requires higher stress for the material to continue plastic flow, resulting in a decrease in the hardening rate b and a slower rate to reach saturation stress (prolonging the hardening process). For compressive residual stress, a decrease in saturation stress Q allows the material to reach a stable plastic flow state more quickly, increasing the hardening rate b and accelerating the entry into the saturation stage.

[0109] Based on the above embodiments, the above Figure 1 There are several possible implementations of step S104, which will be described below. It should be noted that the implementations given below are merely illustrative examples and do not represent all implementations of the embodiments of this application.

[0110] The above step S104 can be used to test two types of working conditions: typical working conditions and extreme working conditions.

[0111] Under extreme conditions during testing, step S104 involves static analysis based on the static strength model and the stress-strain curves of the local material of the structural component, combined with the test conditions and assembly constraints of the structural component, to obtain failure data. This can be:

[0112] Based on the ultimate working conditions of the structural component and the assembly constraints during installation, the equivalent plastic strain distribution of the structural component is determined according to the static strength model, the corrected saturation stress in the plastic stage of the stress-strain curve of the local material of the structural component, and the hardening rate.

[0113] Equivalent plastic strain describes the irreversible strain accumulated in a material during the plastic deformation stage and characterizes the degree of local plastic deformation in the material.

[0114] For example, the above-mentioned structural components are structural components installed on vehicles, and the above-mentioned extreme working conditions may include driving over a deep pothole on one side, forward extreme braking, extreme steering, and side collision with a curb.

[0115] Furthermore, determining whether the structural component has a failure risk based on the failure data can be done as follows:

[0116] Determine whether there is a first region in the structural component where the equivalent plastic strain is greater than or equal to a preset value. If so, the first region is a failure risk region, and the structural component is at risk of failure.

[0117] Based on the ultimate working conditions of the structural component and the assembly constraints during installation, and using the static strength model, the corrected saturation stress in the plastic stage of the stress-strain curve of the local material of the structural component, and the hardening rate, a nonlinear static analysis can be performed on the static strength model of the structural component using finite element analysis software to obtain the equivalent plastic strain distribution on the structural component. Then, it is determined whether the equivalent plastic strain at each node on the static strength model is greater than or equal to a preset value X of the equivalent plastic strain. If a first region exists that is greater than or equal to the preset value of the equivalent plastic strain, then this first region is a failure risk region. This facilitates structural component optimization targeting this first region.

[0118] Optionally, the preset value X can be between 1% and 3%.

[0119] Under typical test conditions, in step S104, based on the static strength model and the stress-strain curves of the local material of the structural component, combined with the test conditions and assembly constraints of the structural component, static analysis is performed to obtain failure data, which can be:

[0120] Based on the typical working conditions of the structural component and the assembly constraints during installation, the Von Mises stress contour map and safety factor of the structural component are determined according to the static strength model and the modified yield strength of the elastic stage of the stress-strain curve of the local material of the structural component.

[0121] For example, if the above-mentioned structural component is a structural component installed on a vehicle, the above-mentioned typical operating conditions may include forward braking, turning left, and going over a convex bump.

[0122] Von Mises stress is an equivalent stress based on distortion energy theory, used to assess whether a material yields under complex multiaxial stress conditions.

[0123] The safety factor (SF) is usually the ratio of the ultimate load-bearing capacity (such as yield strength, tensile strength, etc.) of a sheet metal part to the actual working load. For example, if the yield strength of the sheet metal material is 300 MPa and the actual working stress is 200 MPa, then the safety factor is 1.5.

[0124] Furthermore, determining whether the structural component has a failure risk based on the failure data can be done as follows:

[0125] Determine whether there is a second region in the structural component where the Von Mises stress is greater than or equal to the ratio of the modified yield strength to the safety factor. If so, the second region is a failure risk region, and the structural component is at risk of failure.

[0126] Understandably, the Von Mises stress ≥ modified yield strength ÷ safety factor can be used to analyze and determine whether the local area corresponding to each node in the structural component is a failure risk area based on the Von Mises stress of each node and the modified pre-yield stress.

[0127] Optionally, the aforementioned safety factor is generally 1.1-1.3.

[0128] Based on the above embodiments, when a failure risk area is determined through the above steps S101-S104, the above method may further include:

[0129] Adjust the structure of the area where the structural component has a failure risk, replace the material of the structural component, and adjust any one or more of the stamping parameters, and then re-execute the simulation data of the stamping simulation software to simulate the stamping of the sheet metal to form the structural component and the subsequent steps.

[0130] For example, for failure-risk areas of structural components, reinforcing ribs or ribs can be added to these areas to distribute concentrated loads over a larger area and reduce local stress peaks. Alternatively, the material of the structural component can be upgraded to increase its yield strength or tensile strength. Of course, the stamping parameters can also be adjusted by reverse-analyzing the residual stress distribution (e.g., reducing the blank holder force by 10% → reducing residual stress by 15%).

[0131] Based on the above embodiments, the stamping process of sheet metal can lead to residual stress within the material (some tensile / compressive stresses can reach 20%-30% of the material's yield strength), which in turn affects the material's properties and causes a deviation in the prediction of the yield strength of the positive local material. Therefore, this application first obtains the residual stress field through the stamping simulation in step S101 for subsequent stamping residual stress compensation. Then, it maps the residual stress field to the static strength model in step S102, so that step S103 can combine the stamping process simulation results (residual stress distribution) with the structural static analysis. According to the direction and amplitude of the residual stress, the yield strength and hardening curve of the local material are dynamically adjusted to make the yield strength and hardening curve of the local material of the structural component closer to the actual situation, correcting the stress-strain curve of the local material in the static strength model of the structural component and reducing the prediction deviation of the yield strength of the local material. Thus, step S104, based on the corrected static strength model, loads the test conditions and assembly constraints, and performs static strength analysis using finite element analysis software, improving the accuracy of predicting high-stress areas or high equivalent plastic strain areas. This allows for subsequent optimization based on areas with potential failure risks. Steps S101-S104 are then repeated based on the optimized structure, creating a closed-loop feedback loop. This couples the stamping process with static strength analysis, resulting in a final, failure-free structural component. This reduces the number of design, prototype manufacturing, and bench testing steps, thereby lowering R&D costs and shortening the development cycle.

[0132] The above describes some specific implementations of the residual stress compensation analysis method for structural components provided in this application. Based on this, this application also provides a corresponding device. The device provided in this application will be described below from the perspective of functional modularity.

[0133] See Figure 2 The diagram shows a structural residual stress compensation analysis device for structural components. The structural residual stress compensation analysis device 200 includes:

[0134] The acquisition unit 201 is used to acquire simulation data of the stamping simulation software to simulate the stamping of sheet metal into structural parts. The simulation data includes the residual stress field stored in the form of shell element nodal stress tensor.

[0135] Construction unit 202 is used to map the residual stress field to the static strength mesh of the structural member and construct the static strength model of the structural member;

[0136] Correction unit 203 is used to correct the stress-strain curve of the local material of the structural component based on the mapped residual stress value;

[0137] Analysis unit 204 is used to perform static solutions based on the static strength model and the stress-strain curves of the local materials of the structural component, combined with the test conditions and assembly constraints of the structural component, to obtain failure data, and to determine whether the structural component has a failure risk based on the failure data.

[0138] Based on the aforementioned apparatus, this application obtains the residual stress field through stamping simulation in acquisition unit 201. Then, it maps the residual stress field to the static strength model through construction unit 202, facilitating correction unit 203 to correct the stress-strain curves of local materials in the static strength model of the structural component according to the direction and amplitude of the residual stress, thereby reducing the prediction deviation of the yield strength of local materials. This ensures that analysis unit 204, based on the corrected static strength model, improves the accuracy of predicting high-stress areas or high equivalent plastic strain areas under loading test conditions and assembly constraints. This achieves coupled analysis of stamping process and static strength to obtain a final structural component without failure risk, thereby reducing the number of design, prototype manufacturing, and bench testing operations, lowering R&D costs, and shortening the development cycle.

[0139] In one possible implementation, the building unit 202 is specifically used to set an initial mesh for the structural component, the initial mesh having the same mesh element type as the shell element corresponding to the residual stress field; according to the risk area of ​​the structural component, the initial mesh is locally refined to form the static strength mesh of the structural component, the risk area including fillets and welds; the residual stress field is mapped to multiple nodes of the static strength mesh of the structural component to obtain the static strength model.

[0140] Optionally, the residual stress field can be mapped to multiple nodes of the static strength grid of the structural member using a node mapping method and / or a field variable interpolation method.

[0141] In one possible implementation, the correction unit 203 is specifically used to, for the elastic stage of the stress-strain curve, correct the original yield strength of the sheet material based on the mapped residual stress value, and determine the corrected yield strength of the elastic stage of the stress-strain curve. The larger the absolute value of the mapped residual stress value, the smaller the corrected yield strength. For the plastic stage of the stress-strain curve, in the case of residual tensile stress, the original saturation stress and hardening rate of the plastic stage of the stress-strain curve are corrected based on the mapped residual stress value. In the case of residual compressive stress, the original saturation stress and hardening rate of the plastic stage of the stress-strain curve are corrected based on the mapped residual stress value, to obtain the corrected saturation stress and hardening rate of the plastic stage of the stress-strain curve. The corrected saturation stress increases with increasing tensile stress and decreases with decreasing compressive stress, and the hardening rate decreases with increasing tensile stress and increases with decreasing compressive stress.

[0142] The correction unit 203 is specifically used to subtract the product of the mapped residual stress value and the correction coefficient from the original yield strength to obtain the corrected yield strength.

[0143] The formula for calculating the corrected saturation stress is as follows:

[0144]

[0145] Where Q0 is the saturation stress value of the plate when there is no residual stress, α is the first preset coefficient, and σ y0 σ represents the original yield strength of the plate material. r The mapped residual stress value is σ. r When the stress is tensile, it takes a positive value, σ r When the stress is compressive, the value is negative;

[0146] The formula for calculating the hardening rate is:

[0147]

[0148] Where b0 is the hardening rate of the plate when there is no residual stress, and β is the second preset coefficient.

[0149] In one possible implementation, the analysis unit 204 is specifically used to determine the equivalent plastic strain distribution of the structural component based on the static strength model, the corrected saturation stress of the plastic stage of the stress-strain curve of the local material of the structural component, and the hardening rate, according to the ultimate working condition of the structural component and the assembly constraints during the installation of the structural component.

[0150] Determine whether there is a first region in the structural component where the equivalent plastic strain is greater than or equal to a preset value. If so, the first region is a failure risk region, and the structural component is at risk of failure.

[0151] In one possible implementation, the analysis unit 204 is specifically used to determine the Von Mises stress cloud diagram and safety factor of the structural component based on the typical working conditions of the structural component and the assembly constraints during the installation of the structural component, and based on the static strength model and the modified yield strength of the elastic stage of the stress-strain curve of the local material of the structural component.

[0152] Determine whether there is a second region in the structural component where the Von Mises stress is greater than or equal to the ratio of the modified yield strength to the safety factor. If so, the second region is a failure risk region, and the structural component is at risk of failure.

[0153] In one possible implementation, the apparatus further includes: an optimization unit;

[0154] The optimization unit is used to adjust the structure of the area where the structural component has a failure risk, replace the material of the structural component, and adjust any one or more of the stamping parameters, and re-execute the simulation data of the stamping simulation software to simulate the stamping of the sheet metal to form the structural component and subsequent steps.

[0155] This application also provides corresponding devices and computer storage media for implementing the solutions provided in this application.

[0156] The device includes a memory and a processor. The memory stores instructions or code, and the processor executes the instructions or code to enable the device to perform a structural residual stress compensation analysis method according to any embodiment of this application.

[0157] The computer storage medium stores code, and when the code is run, the device running the code implements a structural component residual stress compensation analysis method according to any embodiment of this application.

[0158] In the embodiments of this application, the terms "first" and "second" (if they exist) are used only as name identifiers and do not represent the order of first and second.

[0159] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps in the methods of the above embodiments can be implemented by means of software plus a general-purpose hardware platform. Based on this understanding, the technical solution of this application can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as a read-only memory (ROM) / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, a server, or a network communication device such as a router) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0160] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0161] The above description is merely an exemplary implementation of this application and is not intended to limit the scope of protection of this application.

Claims

1. A method for residual stress compensation analysis of structural components, characterized in that, include: The simulation data of the stamping of sheet metal into structural parts is obtained by the stamping simulation software. The simulation data includes the residual stress field stored in the form of shell element nodal stress tensor. The residual stress field is mapped onto the static strength mesh of the structural member to construct the static strength model of the structural member; Based on the mapped residual stress value, the stress-strain curve of the local material of the structural component is corrected; Based on the static strength model and the stress-strain curves of the local material of the structural component, combined with the test conditions and assembly constraints of the structural component, static analysis is performed to obtain failure data, and based on the failure data, it is determined whether the structural component has a failure risk.

2. The method according to claim 1, characterized in that, The step of mapping the residual stress field onto the static strength mesh of the structural member to construct the static strength model of the structural member includes: An initial mesh is set for the structural component, and the initial mesh has the same mesh element type as the shell element corresponding to the residual stress field; Based on the risk areas of the structural component, the initial mesh is locally refined to form the static strength mesh of the structural component. The risk areas include fillets and welds. The residual stress field is mapped to multiple nodes of the static strength mesh of the structural member to obtain the static strength model.

3. The method according to claim 2, characterized in that, Mapping the residual stress field to multiple nodes of the static strength mesh of the structural member includes: The residual stress field is mapped to multiple nodes of the static strength grid of the structural member using a node mapping method and / or a field variable interpolation method.

4. The method according to claim 1, characterized in that, The step of correcting the stress-strain curve of the local material of the structural component based on the mapped residual stress value includes: For the elastic stage of the stress-strain curve, the original yield strength of the sheet is corrected based on the mapped residual stress value to determine the corrected yield strength of the elastic stage of the stress-strain curve. The larger the absolute value of the mapped residual stress value, the smaller the corrected yield strength. For the plastic stage of the stress-strain curve, under the condition of residual tensile stress, the original saturation stress and hardening rate of the stress-strain curve in the plastic stage are corrected based on the mapped residual stress value. Under the condition of residual compressive stress, the original saturation stress and hardening rate of the stress-strain curve in the plastic stage are corrected based on the mapped residual stress value, thus obtaining the corrected saturation stress and hardening rate of the stress-strain curve in the plastic stage. The corrected saturation stress increases with increasing tensile stress and decreases with decreasing compressive stress, while the hardening rate decreases with increasing tensile stress and increases with decreasing compressive stress.

5. The method according to claim 4, characterized in that, The step of correcting the original yield strength of the sheet metal based on the mapped residual stress value, and determining the corrected yield strength in the elastic stage of the stress-strain curve, includes: The corrected yield strength is obtained by subtracting the product of the mapped residual stress value and the correction factor from the original yield strength.

6. The method according to claim 4, characterized in that, The formula for calculating the corrected saturation stress is as follows: Where Q0 is the saturation stress value of the plate when there is no residual stress, α is the first preset coefficient, and σ y0 σ represents the original yield strength of the plate material. r The mapped residual stress value is σ. r When the stress is tensile, it takes a positive value, σ r When the stress is compressive, the value is negative; The formula for calculating the hardening rate is: Where b0 is the hardening rate of the plate when there is no residual stress, and β is the second preset coefficient.

7. The method according to claim 4, characterized in that, The test condition is an extreme condition. Based on the static strength model and the stress-strain curves of the local material of the structural component, combined with the test condition and assembly constraints of the structural component, static solutions are performed to obtain failure data, including: Based on the ultimate working conditions of the structural component and the assembly constraints during installation, the equivalent plastic strain distribution of the structural component is determined according to the static strength model, the corrected saturation stress in the plastic stage of the stress-strain curve of the local material of the structural component, and the hardening rate. The process of determining whether the structural component has a failure risk based on the failure data includes: Determine whether there is a first region in the structural component where the equivalent plastic strain is greater than or equal to a preset value. If so, the first region is a failure risk region, and the structural component is at risk of failure.

8. The method according to claim 4, characterized in that, The test conditions are typical conditions. Based on the static strength model and the stress-strain curves of the local material of the structural component, combined with the test conditions and assembly constraints of the structural component, static solutions are performed to obtain failure data, including: Based on the typical working conditions of the structural component and the assembly constraints during installation, the Von Mises stress cloud diagram and safety factor of the structural component are determined based on the static strength model and the modified yield strength of the elastic stage of the stress-strain curve of the local material of the structural component. The process of determining whether the structural component has a failure risk based on the failure data includes: Determine whether there is a second region in the structural component where the Von Mises stress is greater than or equal to the ratio of the modified yield strength to the safety factor. If so, the second region is a failure risk region, and the structural component is at risk of failure.

9. The method according to claim 7 or 8, characterized in that, The method further includes: Adjust the structure of the area where the structural component has a failure risk, replace the material of the structural component, and adjust any one or more of the stamping parameters, and then re-execute the simulation data of the stamping simulation software to simulate the stamping of the sheet metal to form the structural component and the subsequent steps.

10. A residual stress compensation analysis device for structural components, characterized in that, include: The acquisition unit is used to acquire simulation data of the stamping simulation software to simulate the stamping of sheet metal into structural parts. The simulation data includes the residual stress field stored in the form of shell element nodal stress tensor. A building block is used to map the residual stress field to the static strength mesh of the structural member, thereby constructing the static strength model of the structural member. The correction unit is used to correct the stress-strain curve of the local material of the structural component based on the mapped residual stress value. The analysis unit is used to perform static solutions based on the static strength model and the stress-strain curves of the local material of the structural component, combined with the test conditions and assembly constraints of the structural component, to obtain failure data, and to determine whether the structural component has a failure risk based on the failure data.

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