An extrusion deformation state detection method and system, an electronic device, and a storage medium

Abstract

The application discloses an extrusion deformation state detection method and system, electronic equipment and a storage medium, and relates to the technical field of extrusion deformation detection. The method comprises the following steps: determining the deformation calculation method corresponding to each node / integration point according to the initial data of each time step in a time step iteration manner, and then determining the extrusion deformation data of the target measured object at the time step according to the corresponding deformation calculation method of each node / integration point, and obtaining the extrusion deformation state of the object at all time points through time step iteration. The application selects the corresponding deformation calculation method for deformation operation according to different nodes / integration points, retains the operation advantages of the time-space stable node integration algorithm and the node smooth finite element algorithm, and can realize high-precision and high-efficiency extrusion deformation state detection.

Description

Technical Field

[0001] This invention relates to the field of extrusion deformation detection technology, and in particular to a method, system, electronic device, and storage medium for detecting extrusion deformation state. Background Technology

[0002] The shapes of various products on the market are usually formed by extruding materials under pressure in a mold. During the extrusion process, it is necessary to observe the deformation of the material to adjust the force application point or study the deformation. In existing technologies, the finite element method (FEM) is commonly used to detect the extrusion deformation of objects. The FEM requires high-precision structural meshes (quadrilaterals or hexahedrons), has low computational efficiency, high mesh requirements, and cannot adapt to the calculation of large-scale complex models. The smoothed finite element method, based on the FEM, has several superior characteristics. The nodal smoothed finite element algorithm has good convergence for implicit problems and is free from self-locking, but it cannot demonstrate stability for explicit dynamic large deformation analysis, mainly manifesting as the generation of singular vibration modes. The spacetime stable nodal integral algorithm, based on the nodal smoothed finite element algorithm, has a much higher accuracy in solving dynamic problems than the nodal smoothed finite element algorithm. However, its computation time is much longer. Currently, there is no method that can effectively combine these two algorithms, therefore, it cannot achieve high-precision and high-efficiency detection of the extrusion deformation of the tested object. Summary of the Invention

[0003] The purpose of this invention is to provide a method, system, electronic device, and storage medium for detecting extrusion deformation state, which can achieve high-precision and high-efficiency detection of extrusion deformation state.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] A method for detecting extrusion deformation state includes:

[0006] The input file is read to obtain the geometric grid and object information of the target object at the initial moment. Each grid in the geometric grid is a cell, and each intersection of the geometric grid is a node. The object information includes: material parameters, initial conditions, and contact boundary conditions. The material parameters include elastic modulus, Poisson's ratio, and mass density. The initial conditions are determined based on the motion state of the target object at the initial moment. The contact boundary conditions include the contact coordinates of the target object when it is subjected to compression.

[0007] Determine the grid information of the geometric grid at the initial moment; the grid information includes: node coordinates, cell information, and a preset average node ratio;

[0008] Entering the time step iteration, based on the mesh information and the extrusion deformation data at the start of the current time step, the deformation calculation method for each node / integration point in the current time step is determined; the extrusion deformation data includes stress, strain, displacement, and acceleration; the integration point is the integration point used for numerical integration in the spacetime stable node integration algorithm or the node smoothed finite element method; the deformation calculation method is the spacetime stable node integration algorithm or the node smoothed finite element algorithm.

[0009] Using the corresponding deformation calculation method, the compression deformation data of each node / integral point at the current time step are calculated based on the object information of the target object at the current time step; where the node data includes displacement and acceleration, and the integration point data includes stress and strain.

[0010] Determine whether the end time of the current time step is the end time when the target object being measured is compressed, and obtain the first determination result;

[0011] If the first judgment result is negative, then the data is updated according to the compression deformation of each node / integral point at the end of the current time step, and the updated result is used as the compression deformation data at the start of the next time step.

[0012] If the first judgment result is yes, then the compression deformation state of the target test object is determined based on the compression deformation data of all nodes / integral points at all times when the target test object is compressed.

[0013] Optionally, based on the grid information and the extrusion deformation data at the start of the current time step, the deformation calculation method for each node / integral point at the current time step is determined, specifically including:

[0014] For any node in the geometric grid at the start of the current time step, determine whether the node is a boundary node to obtain a second determination result; the boundary node is a node located at the edge of the geometric grid.

[0015] If the second judgment result is yes, then the deformation calculation method of the node / integration point at the current time step is determined to be the space-time stable node integration algorithm;

[0016] If the second judgment result is negative, then judge whether the time step is less than 100 to obtain the third judgment result;

[0017] If the third judgment result is yes, then the deformation calculation method of the node / integration point at the current time step is determined to be the space-time stable node integration algorithm;

[0018] If the third judgment result is negative, then further judge whether the current time step is an integer multiple of 100 to obtain the fourth judgment result;

[0019] If the result of the fourth judgment is negative, then the calculation method of the previous time step will continue to be used;

[0020] If the fourth judgment result is yes, then further judge whether the algorithm of the previous time step is the nodal smooth finite element method to obtain the fifth judgment result;

[0021] If the fifth judgment result is yes, then further judge whether the stress is greater than the preset average ratio of nodes to obtain the sixth judgment result;

[0022] If the fifth judgment result is negative, then further judgment is made on whether the stress is less than the preset average ratio of nodes, and the seventh judgment result is obtained.

[0023] If the sixth judgment result is yes, then the deformation calculation method of the node / integration point at the current time step is determined to be the space-time stable node integration algorithm.

[0024] If the result of the sixth judgment is negative, then the deformation calculation method of the node / integral point at the current time step is determined to be the nodal smooth finite element method;

[0025] If the result of the seventh judgment is yes, then the deformation calculation method of the node / integral point at the current time step is determined to be the nodal smooth finite element method;

[0026] If the seventh judgment result is negative, then the deformation calculation method of the node / integral point at the current time step is determined to be the space-time stable node integration algorithm.

[0027] Optionally, determining whether the node is a boundary node specifically includes:

[0028] Calculate the boundary angle of the node;

[0029] If the boundary angle is equal to 360 degrees, then the node is determined not to be a boundary node.

[0030] If the boundary angle is less than 360 degrees, then the node is determined to be a boundary node.

[0031] Optionally, a corresponding deformation calculation method is used to calculate the compression deformation data of each node / integration point at the end of the current time step based on the object information of the target object at the current time step, specifically including:

[0032] Using the corresponding deformation calculation method, the force data of each node / integration point at the current time step is calculated based on the object information of the target object at the current time step; the force data includes contact force, internal force and external force.

[0033] Based on the time-step iterative algorithm and the force data, the compression deformation data of each node / integral point in the current time step are determined.

[0034] Optionally, it also includes: generating a stress contour map based on the stress in the extrusion deformation data.

[0035] The present invention also provides a system for detecting extrusion deformation state, comprising:

[0036] The data loading module is used to read the input file and obtain the geometric grid and object information of the target object at the initial moment. Each grid in the geometric grid is a cell, and each intersection of the geometric grid is a node. The object information includes: material parameters, initial conditions, and contact boundary conditions. The material parameters include elastic modulus, Poisson's ratio, and mass density. The initial conditions are determined based on the motion state of the target object at the initial moment. The contact boundary conditions include the contact coordinates of the target object when it is subjected to compression.

[0037] The grid information determination module is used to determine the grid information of the geometric grid at the initial moment; the grid information includes: node coordinates, cell information, and a preset average node ratio.

[0038] The deformation calculation method determination module is used to enter the time step iteration and determine the deformation calculation method for each node / integration point in the current time step based on the mesh information and the extrusion deformation data at the start of the current time step. The extrusion deformation data includes stress, strain, displacement, and acceleration. The integration points are integration points used for numerical integration in the spacetime stable node integration algorithm or the node smoothed finite element method. The deformation calculation method is either the spacetime stable node integration algorithm or the node smoothed finite element algorithm.

[0039] The deformation calculation module is used to calculate the compression deformation data of each node / integral point in the current time step based on the object information of the target object in the current time step using the corresponding deformation calculation method; where the node data includes displacement and acceleration, and the integration point data includes stress and strain.

[0040] The end determination module is used to determine whether the end time of the current time step is the end time when the target object being tested is compressed, and to obtain the first determination result;

[0041] The first judgment result module is used to update the data based on the compression deformation of each node / integral point at the end of the current time step if the first judgment result is negative, and use the updated result as the compression deformation data at the start of the next time step.

[0042] The second judgment result module is used to determine the compression deformation state of the target test object based on the compression deformation data of all nodes / integral points at all times when the target test object is compressed, if the first judgment result is yes.

[0043] The present invention also provides an electronic device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to cause the electronic device to perform the extrusion deformation state detection method described above.

[0044] The present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the extrusion deformation state detection method as described above.

[0045] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0046] This invention discloses a method, system, electronic device, and storage medium for detecting extrusion deformation state. The method includes determining the deformation calculation method corresponding to each node / integration point based on the initial data of each time step through time step iteration, and then determining the extrusion deformation data of the target object at that time step based on the corresponding deformation calculation method of each node / integration point. The extrusion deformation state of the object at all times is obtained through time step iteration. This invention retains the computational advantages of both the spacetime stable node integration algorithm and the node smooth finite element algorithm by selecting the corresponding deformation calculation method for different nodes / integration points, thus achieving high-precision and high-efficiency extrusion deformation state detection. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a flowchart of the extrusion deformation state detection method of the present invention;

[0049] Figure 2 This is a logic flowchart of this embodiment;

[0050] Figure 3 This is a schematic diagram illustrating the method for determining the deformation at the integration point in this embodiment.

[0051] Figure 4 This is a schematic diagram showing the geometric dimensions and initial state of the target object in Example 1;

[0052] Figure 5 This is the final stress contour plot from Example 1;

[0053] Figure 6 This is a schematic diagram of the billet extrusion deformation state results in Example 1;

[0054] Figure 7 This is a schematic diagram of the calculation method used at different times in the high-density grid in Example 1 (where the light-colored area uses the space-time stable nodal integration algorithm SNS-FEM, and the dark-colored area uses the nodal smooth finite element method NS-FEM).

[0055] Figure 8 This is a comparison chart of the computation time of different algorithms under various grid densities in Example 1;

[0056] Figure 9 This is a schematic diagram showing the geometric dimensions and initial state of the target object in Example 2;

[0057] Figure 10 This is a schematic diagram showing the overall stress, contact surface stress, and deformation of the target object in Example 2;

[0058] Figure 11 This is a comparison chart of the computation time of different algorithms under different grid densities in Example 2;

[0059] Figure 12 This is a structural block diagram of the extrusion deformation state detection system of the present invention. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] The purpose of this invention is to provide a method, system, electronic device, and storage medium for detecting extrusion deformation state, which can achieve high-precision and high-efficiency detection of extrusion deformation state.

[0062] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0063] like Figure 1 As shown, the present invention provides a method for detecting extrusion deformation state, comprising:

[0064] Step 100: Read the input file to obtain the geometric grid and object information of the target object at the initial moment; each grid in the geometric grid is a cell, and each intersection in the geometric grid is a node; the object information includes: material parameters, initial conditions, and contact boundary conditions; the material parameters include elastic modulus, Poisson's ratio, and mass density; the initial conditions are determined based on the motion state of the target object at the initial moment; the contact boundary conditions include the contact coordinates of the target object when it is subjected to compression.

[0065] Step 200: Determine the grid information of the geometric grid at the initial moment; the grid information includes: node coordinates, cell information and preset node average ratio.

[0066] Step 300: Enter time step iteration. Based on the mesh information and the extrusion deformation data at the start of the current time step, determine the deformation calculation method for each node / integration point in the current time step. The extrusion deformation data includes stress, strain, displacement, and acceleration. The integration points are the integration points used for numerical integration in the spacetime stable nodal integration algorithm or the nodal smoothed finite element method. The deformation calculation method is either the spacetime stable nodal integration algorithm or the nodal smoothed finite element algorithm. The first time step of the extrusion deformation data at the start of the current time step is obtained from the initial data, and the rest are obtained from the previous time step.

[0067] Step 400: Using the corresponding deformation calculation method, calculate the compression deformation data of each node / integral point in the current time step based on the object information of the target object at the current time step; where the node data includes displacement and acceleration, and the integration point data includes stress and strain.

[0068] Step 500: Determine whether the end time of the current time step is the end time when the target object is compressed, and obtain the first judgment result.

[0069] Step 600: If the first judgment result is negative, then update the data according to the compression deformation of each node / integral point at the end of the current time step, and use the updated result as the compression deformation data at the start of the next time step.

[0070] Step 700: If the first judgment result is yes, then determine the compression deformation state of the target object based on the compression deformation data of all nodes / integral points at all times when the target object is compressed.

[0071] As a specific implementation of step 300, the following steps are included:

[0072] The first step is to determine whether any node in the geometric grid at the start of the current time step is a boundary node, and obtain the second determination result; a boundary node is a node located at the edge of the geometric grid.

[0073] The second step is to determine the deformation calculation method of the node / integration point at the current time step as the space-time stable node integration algorithm if the second judgment result is yes.

[0074] Third, if the second judgment result is negative, then determine whether the time step is less than 100 to obtain the third judgment result.

[0075] Fourth step: If the result of the third judgment is yes, then the deformation calculation method of the node / integration point at the current time step is determined to be the space-time stable node integration algorithm.

[0076] Fifth, if the third judgment result is negative, then further judge whether the current time step is an integer multiple of 100 to obtain the fourth judgment result.

[0077] Step 6: If the result of the fourth judgment is negative, then continue to use the calculation method of the previous time step.

[0078] Step 7: If the fourth judgment result is yes, then further judge whether the algorithm of the previous time step is the nodal smooth finite element method, and obtain the fifth judgment result.

[0079] Step 8: If the fifth judgment result is yes, then further judge whether the stress is greater than the preset average node ratio to obtain the sixth judgment result.

[0080] In the ninth step, if the fifth judgment result is negative, then further judge whether the stress is less than the preset average ratio of nodes to obtain the seventh judgment result.

[0081] Step 10: If the result of the sixth judgment is yes, then the deformation calculation method of the node / integration point at the current time step is determined to be the space-time stable node integration algorithm.

[0082] In the eleventh step, if the result of the sixth judgment is negative, then the deformation calculation method of the node / integral point in the current time step is determined to be the nodal smooth finite element method.

[0083] Step 12: If the result of the seventh judgment is yes, then the method for calculating the deformation of the node / integral point at the current time step is determined to be the nodal smooth finite element method.

[0084] Step 13: If the result of the seventh judgment is negative, then the deformation calculation method of the node / integration point at the current time step is determined to be the space-time stable node integration algorithm.

[0085] The determination method in the first step of step 300 specifically includes:

[0086] Calculate the boundary angle of the node; if the boundary angle is equal to 360 degrees, then the node is determined not to be a boundary node; if the boundary angle is less than 360 degrees, then the node is determined to be a boundary node. The boundary angle refers to the sum of the angles of the surrounding cells of the node.

[0087] As a specific implementation of step 400, the following steps are included:

[0088] The first step is to use the corresponding deformation calculation method to calculate the force data of each node / integration point in the current time step based on the object information of the target object at the current time step; the force data includes contact force, internal force and external force.

[0089] The second step is to determine the compression deformation data of each node / integral point of the time step based on the time step iterative algorithm and the force data.

[0090] In addition, based on the above method steps, in order to analyze the accuracy of the method, the method further includes: generating a stress cloud map based on the stress in the extrusion deformation data.

[0091] Based on the above method, the following specific embodiments are provided:

[0092] Example 1

[0093] like Figure 4 As shown, a square blank measuring 90cm*20cm is placed in a rigid mold and extruded by a rigid punch above the workpiece.

[0094] The material parameters are as follows: elastic modulus E = 120 GPa, Poisson's ratio v = 0.3, initial yield stress σ0 = 400 MPa, hardening modulus H = 100 MPa, and mass density ρ = 780 kg / m³. 3 The coefficient of friction between the punch and the blank is 0.3, and the coefficient of friction between the die and the blank is 0.35.

[0095] The punch is set to move downwards at a speed of 10 m / s.

[0096] To more clearly demonstrate the efficiency and accuracy of this method, three mesh densities can be used during the solution process. The mesh density options are: low density mesh (510 nodes, 908 elements, unstructured triangular mesh); medium density mesh (866 nodes, 1584 elements, unstructured triangular mesh); and high density mesh (1924 nodes, 3626 elements, unstructured triangular mesh).

[0097] like Figures 2-3 As shown, the main calculation steps are as follows:

[0098] Step 1: Read in the mesh information and object information, which mainly includes node coordinates, element information, material parameters, initial conditions, contact boundary conditions, and set the average node ratio, etc.

[0099] Initial conditions refer to the values ​​of displacement, velocity, acceleration, etc., assigned to certain nodes on the billet at the initial moment, such as... Figure 9 In this process, these nodes all impact the contact surface with an initial velocity v.

[0100] The above node information is set according to the specific problem. The material parameters are based on the actual material parameters in the problem. The node coordinates and element information can be obtained by dividing the geometry into a mesh using commercial software (the node information includes node coordinates, and the element information includes which nodes each element is composed of). The initial conditions and contact boundary conditions are set according to the actual initial motion state and contact situation of the problem (the contact boundary conditions refer to the contact information between different structures or between a structure and an external rigid body, and all node information that may come into contact is input).

[0101] Among them, the geometric grid uses unstructured grid cells, which have the advantages of easy control of grid size and node density, strong grid self-adaptation ability, and automatic generation.

[0102] Step 2: Based on the read node information, first perform a time step loop. During the loop, perform a node sequence loop to determine whether it is a boundary node.

[0103] Step 3: For boundary nodes, the space-time stable nodal integration algorithm (SNS-FEM algorithm) is used for subsequent calculations. Using the SNS-FEM algorithm for boundary nodes effectively ensures that mesh distortion does not occur at the boundary nodes (the nodal smoothing finite element method NS-FEM is prone to distortion at the boundaries), thus obtaining reliable accuracy.

[0104] Step 4: If it is not a boundary node, proceed with the 100-step time step determination process. This obtains data on stress, internal forces, and external forces at internal nodes / integration points. The set node average ratio in the 100-step time step determination process reorders the stresses at the nodes / integration points of the determination time step, such as: σ i >σ j >...>σ n >σ m In the formula, i, j, m, and n are all random node numbers. Then, the stress of the nodes / integral points with stress in the first 40% (this setting can effectively control distortion) is taken as the node stress setting value. Before the next judgment, the stress is greater than this setting and SNS-FEM is used, while other nodes / integral points use NS-FEM.

[0105] The time step loop is used to determine the time step once every 100 steps. If too few time steps are selected in the loop, the number of method transitions will increase, which will easily lead to the accumulation of method transition errors. If too many time steps are selected in the loop, the number of NS-FEM calculations will increase, which will affect the calculation accuracy.

[0106] To ensure computational accuracy and avoid mesh distortion at the outset, all nodes / integration points in the first 100 time steps employ a space-time stable node integration algorithm.

[0107] The determination process involves deciding whether to switch methods for nodes / integral points. That is, the methods used for nodes / integral points may differ before and after the determination. If SNS-FEM is used for nodes before determination, then if the stress at the node / integral point is less than the set value after determination, a method switch is required; otherwise, no switch is needed. If NS-FEM is used for nodes / integral points before determination, and the stress at the node / integral point is greater than the set value after determination, then a method switch is required; otherwise, no switch is needed.

[0108] During the algorithm conversion process, SNS-FEM is transformed into the NS-FEM method, and its parameters are solved as follows: the SNS-FEM Cauchy stress σ' is iteratively transformed into the NS-FEM Cauchy stress σ, and the SNS-FEM equivalent plastic strain is... Iterative transformation into NS-FEM plastic strain They are represented by the following formulas respectively:

[0109]

[0110] Where, σ' i and These represent the Cauchy stress and equivalent plastic strain values ​​at each integration point of the SNS-FEM.

[0111] The conversion from NS-FEM to SNS-FEM involves the following parameter solution: the NS-FEM Cauchy stress σ is iteratively transformed into the SNS-FEM Cauchy stress σ', and the NS-FEM plastic strain... Iterative transformation into SNS-FEM plastic strain They are represented by the following formulas respectively:

[0112]

[0113] Step 5: The node loop ends, and the stress, strain, displacement, acceleration, etc. of each node / integral point are solved.

[0114] During the cyclic operation of the time step, the dynamic control equations include the laws of conservation of mass, linear momentum, and energy, and their formulas are shown below:

[0115] Conservation of mass:

[0116] ρJ=ρ0J0=ρ0

[0117] Conservation of linear momentum:

[0118]

[0119] Energy conservation:

[0120]

[0121] Where ρ0 and ρ are the initial and current mass densities, respectively, P represents the nominal stress, F represents the deformation gradient, and J is the Jacobian of the deformation gradient. 'b' represents internal energy per unit mass, and 'b' represents physical force per unit mass. The differential operator symbol for a vector is used, and J0 represents the Jacobian of the initial deformation gradient (equal to 1). It represents the second derivative of displacement with respect to time, i.e., acceleration.

[0122] The nominal stress P is solved at time step n as follows:

[0123] P n =J n (F n ) -1 σ n ;

[0124] During the cyclic calculation of the time step, the formula for its discrete motion equation is as follows:

[0125]

[0126] in, The external force representing node I, For the contact force at node I, Let be the internal force at node I.

[0127] The contact force at node I is calculated as follows:

[0128]

[0129] Where, φ I Denotes the shape function, q N q represents the normal contact force. T t represents the tangential contact force, and t represents the unit tangential vector.

[0130] The external forces at node I are solved as follows:

[0131]

[0132] Where Ω0 represents the original integration domain, This represents the unit tangent vector on the boundary.

[0133] The internal forces at node I are solved as follows:

[0134]

[0135] in, The notation for differential operators representing vectors.

[0136] The entire process then employs an iterative method, recursively deriving the results for subsequent time steps based on the initial values ​​of velocity, acceleration, displacement, and contact boundary conditions. After each time step calculation, the nodal / integral point stress, strain, displacement, and acceleration results for that time step are obtained. The displacement and acceleration results are primarily obtained after selecting the method and determining the parameters to be used. The displacement results for time step n+1 are as follows.

[0137] Displacement: u n+1 =u n +v n+1 / 2 ·Δt

[0138] In the formula, u represents displacement, v represents velocity, and Δt represents the time difference between the previous moment and the current moment, where v n+1 / 2 =v n-1 / 2 +a n ·Δt.

[0139] The acceleration at time step n is calculated as follows.

[0140] Acceleration: In the formula, m represents the mass of a node (the mass of the total mass of the model after being evenly distributed among the nodes).

[0141] After selecting the method, and converting it from the space-time stable nodal integration algorithm (SNS-FEM algorithm) to the nodal smooth finite element algorithm (NS-FEM algorithm), or vice versa, the strain and stress can be solved using the following formulas. When the time step is n, it is as follows:

[0142] Deformation gradient F: Where δ ij This is the delta function.

[0143] Velocity gradient L:

[0144] Effective deformation increment ΔW n and effective spinor ΔD n They are respectively:

[0145]

[0146]

[0147] Then, the incremental rotation tensor Q is obtained. n+1 for: Where I is a unit vector.

[0148] The stress update uses a radial return algorithm. The initial test stress at time step n+1 is given as follows: In the formula C σJ The material response matrix is ​​related to the Jaumann objective law. For stress testing, the Cauchy stress value σ on the yield surface can be obtained by following the calculation process of the radial return algorithm. n+1 .

[0149] The nominal stress is P n+1 =J n+1 (F n+1 ) -1 σ n+1 J n+1 Jacobi for n+1 steps.

[0150] Furthermore, the internal forces at step n+1 can be solved using the formula, and the external forces can be determined based on the given conditions, thereby solving for the acceleration a. n+1 Then proceed to the next time step to solve.

[0151] Step 6: After the time step loop ends, calculate the CPU time and terminate the calculation. The CPU time used to solve the problem using the algorithm is the sole indicator of problem-solving efficiency. When using the same computer and under the same initialization conditions during the problem-solving process, the results are convincing.

[0152] To illustrate the implementation of the specific method conversion process, the following explanation is provided first:

[0153] Compared to the NS-FEM method, the SNS-FEM method improves stress distribution by adding auxiliary integration points as stress evaluation points. In short, the former constructs a polygonal integration region, selecting nodes within this region as unique integration points; the latter constructs a circular region with the same area as the polygon (for two-dimensional problems) and selects four points within this region as integration points. In each time step, the deformation parameters of each node / integration point in both methods iterate continuously, so during method conversion, iterative substitution of different methods is necessary.

[0154] Analysis of results from Example 1:

[0155] The accuracy of this case is mainly determined by observing the stress cloud map. This embodiment provides a separate stress cloud map of the node locations using the SNS-FEM method, which clearly shows which node locations used the SNS-FEM method, thus demonstrating the superiority of the method. The locations where the SNS-FEM method was used are all locations with large stress and deformation, thereby enhancing stability and calculation accuracy, which is consistent with the expected results.

[0156] This embodiment demonstrates the node locations obtained by applying the SNS-FEM method to high grid densities, such as... Figure 7 As shown (where the light-colored areas use the space-time stable nodal integration algorithm SNS-FEM, and the dark-colored areas use the nodal smoothing finite element method NS-FEM), the final stress contour map results obtained in this embodiment, along with the SNS-FEM method and the edge smoothing finite element method (ES-FEM, which achieves high levels of computational accuracy and efficiency), are as follows. Figure 5 As shown in the figure, this method can effectively guarantee the accuracy requirements. The billet deformation results of this embodiment, compared with NS-FEM and SNS-FEM, are as follows: Figure 6 As shown, this embodiment exhibits high stability. Compared to other methods, the solution time of this embodiment is as follows: Figure 8 As shown, it can be seen that the computational efficiency of this embodiment is quite impressive.

[0157] Example 2

[0158] like Figure 9 As shown, the lower surface of the cylindrical aluminum rod is in contact with a smooth rigid wall, and the rod collides with the rigid wall downwards at a speed of v = 478 m / s.

[0159] The material parameters are as follows: elastic modulus E = 78.2 GPa, Poisson's ratio v = 0.3, and mass density ρ = 2700 kg / m³. 3 To facilitate comparison of the superiority of different methods, the model was discretized into three linear tetrahedral mesh elements: B1, B2, and B3. B1 has 1212 nodes and 4839 elements; B2 has 2425 nodes and 10831 elements; and B3 has 7831 nodes and 35571 elements. The simulation time was 50 microseconds.

[0160] The calculation steps in Example 2 are the same as those in Example 1, and will not be repeated here.

[0161] It is worth noting that the calculation steps for three-dimensional dynamic problems are the same as those for two-dimensional dynamic problems, but the formulas for three-dimensional dynamic problems are slightly different when implementing algorithm conversion.

[0162] The conversion from SNS-FEM to NS-FEM yields the following solutions for Cauchy stress and equivalent plastic strain:

[0163]

[0164] The conversion from NS-FEM to SNS-FEM yields the following Cauchy stress and equivalent plastic strain:

[0165]

[0166] The meanings of the parameters in the formula are consistent with those of the two-dimensional problem.

[0167] Analysis of results from Example 2:

[0168] Although this embodiment deals with a three-dimensional dynamic problem, its calculation results exhibit high stability, good accuracy, and high efficiency. For example... Figure 10 As shown, the stress contour plots of NS-FEM, SNS-FEM, and this embodiment under B3 mesh elements are compared; as... Figure 11 As shown, the computation time of SNS-FEM and the embodiment is compared. It can be seen that this embodiment still maintains good stability and accuracy in three-dimensional dynamic problems. Regarding computational efficiency, due to the accuracy limitations of NS-FEM, this embodiment only compares SNS-FEM with the method of this invention; the computational efficiency of this embodiment is significantly faster than that of the SNS-FEM method.

[0169] like Figure 12 As shown, the present invention also provides a system for detecting extrusion deformation state, comprising:

[0170] The data loading module is used to read the input file and obtain the geometric grid and object information of the target object at the initial moment. Each grid in the geometric grid is a cell, and each intersection of the geometric grid is a node. The object information includes: material parameters, initial conditions, and contact boundary conditions. The material parameters include elastic modulus, Poisson's ratio, and mass density. The initial conditions are determined based on the motion state of the target object at the initial moment. The contact boundary conditions include the contact coordinates of the target object when it is subjected to compression.

[0171] The grid information determination module is used to determine the grid information of the geometric grid at the initial moment; the grid information includes: node coordinates, cell information and preset node average ratio.

[0172] The deformation calculation method determination module is used to enter the time step iteration. Based on the mesh information and the extrusion deformation data at the start of the current time step, it determines the deformation calculation method for each node / integration point in the current time step. The extrusion deformation data includes stress, strain, displacement, and acceleration. The integration points are the integration points used for numerical integration in the spacetime stable nodal integration algorithm or the nodal smooth finite element method. The deformation calculation method is either the spacetime stable nodal integration algorithm or the nodal smooth finite element algorithm.

[0173] The deformation calculation module is used to calculate the compression deformation data of each node / integral point in the current time step based on the object information of the target object in the current time step using the corresponding deformation calculation method; the node data includes displacement and acceleration, and the integration point data includes stress and strain.

[0174] The termination judgment module is used to determine whether the end time of the current time step is the termination time when the target object being measured is compressed, and to obtain the first judgment result.

[0175] The first judgment result module is used to update the data based on the compression deformation of each node / integral point at the end of the current time step if the first judgment result is negative, and use the updated result as the compression deformation data at the start of the next time step.

[0176] The second judgment result module is used to determine the compression deformation state of the target object based on the compression deformation data of all nodes / integral points at all times when the target object is compressed, if the first judgment result is yes.

[0177] The present invention also provides an electronic device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to cause the electronic device to perform the extrusion deformation state detection method described above.

[0178] The present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the extrusion deformation state detection method as described above.

[0179] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0180] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method of detecting an extrusion deformation state, characterized by, The method comprises the following steps: reading an input file to obtain a geometric grid and object information of a target object at an initial time; each grid in the geometric grid is a unit, and each intersection in the geometric grid is a node; the object information comprises material parameters, initial conditions and contact boundary conditions; the material parameters comprise an elastic modulus, a Poisson's ratio and a mass density; the initial conditions are determined according to a motion state of the target object at the initial time; and the contact boundary conditions comprise contact coordinates of the target object when the target object is subjected to extrusion; determining grid information of the geometric grid at the initial time; the grid information comprises node coordinates, unit information and a preset node average ratio; entering a time step iteration, and determining a deformation calculation method of each node / integration point at a current time step according to the grid information and extrusion deformation data at a starting time of the current time step; specifically, for any node in the geometric grid at the starting time of the current time step, determining whether the node is a boundary node to obtain a second determination result; the boundary node is a node at an edge of the geometric grid; if the second determination result is yes, determining that the deformation calculation method of the node / integration point at the current time step is a time-space stable node integration algorithm; if the second determination result is no, determining whether the time step is less than 100 to obtain a third determination result; if the third determination result is yes, determining that the deformation calculation method of the node / integration point at the current time step is the time-space stable node integration algorithm; if the third determination result is no, further determining whether the current time step number is an integer multiple of 100 to obtain a fourth determination result; if the fourth determination result is no, continuing to use a calculation method of a previous time step; if the fourth determination result is yes, further determining whether an algorithm of the previous time step is a node smoothed finite element method to obtain a fifth determination result; if the fifth determination result is yes, further determining whether stress is greater than the preset node average ratio to obtain a sixth determination result; if the fifth determination result is no, further determining whether stress is less than the preset node average ratio to obtain a seventh determination result; if the sixth determination result is yes, determining that the deformation calculation method of the node / integration point at the current time step is the time-space stable node integration algorithm; if the sixth determination result is no, determining that the deformation calculation method of the node / integration point at the current time step is the node smoothed finite element method; if the seventh determination result is yes, determining that the deformation calculation method of the node / integration point at the current time step is the node smoothed finite element method; if the seventh determination result is no, determining that the deformation calculation method of the node / integration point at the current time step is the time-space stable node integration algorithm; the extrusion deformation data comprises stress, strain, displacement and acceleration; the integration point is an integration point used for numerical integration in the time-space stable node integration algorithm or the node smoothed finite element method; and the deformation calculation method is the time-space stable node integration algorithm or the node smoothed finite element algorithm. According to object information of the target measured object at a current time step, using a corresponding deformation calculation method, extrusion deformation data of each node / integration point at the current time step is calculated, wherein the node data includes displacement and acceleration, and the integration point data includes stress and strain; It is judged whether the end moment of the current time step is the termination moment of the extrusion of the target measured object, and a first judgment result is obtained; If the first judgment result is no, data updating is performed according to the extrusion deformation of each node / integration point at the end moment of the current time step, and the updating result is taken as the extrusion deformation data of the starting moment of the next time step; If the first judgment result is yes, the extrusion deformation state of the target measured object is determined according to the extrusion deformation data of all nodes / integration points of the target measured object at all moments of extrusion.

2. The extrusion deformation state detection method according to claim 1, wherein whether the node is a boundary node is judged, and the judgment specifically includes: The boundary angle of the node is calculated; If the boundary angle is equal to 360 degrees, it is determined that the node is not a boundary node; If the boundary angle is less than 360 degrees, it is determined that the node is a boundary node. According to object information of the target measured object at a current time step, using a corresponding deformation calculation method, extrusion deformation data of each node / integration point at the end moment of the current time step is calculated, and specifically includes:

3. The extrusion deformation state detection method according to claim 1, characterized by According to object information of the target measured object at a current time step, using a corresponding deformation calculation method, force data of each node / integration point at the current time step is calculated, and the force data includes contact force, internal force and external force; According to the time step iteration algorithm and the force data, the extrusion deformation data of each node / integration point at the current time step is determined. Further including:

4. The extrusion deformation state detection method according to claim 1, characterized by A stress nephogram is generated according to the stress in the extrusion deformation data. Including:

5. An extrusion deformation state detection system characterized by comprising: A data loading module is configured to read an input file to obtain a geometric grid and object information of the target measured object at an initial moment; Each grid in the geometric grid is a unit, and each intersection point in the geometric grid is a node; The object information includes material parameters, initial conditions and contact boundary conditions; the material parameters include elastic modulus, Poisson's ratio and mass density; the initial conditions are determined according to the motion state of the target measured object at the initial moment; and the contact boundary conditions include contact coordinates of the target measured object when it is extruded; A grid information determination module is configured to determine grid information of the geometric grid at the initial moment; the grid information includes node coordinates, unit information and a preset node average ratio; A grid information determination module is configured to determine grid information of the geometric grid at the initial moment; the grid information includes node coordinates, unit information and a preset node average ratio; The deformation calculation method determination module is configured to enter time step iteration, determine a deformation calculation method of each node / integration point in a current time step according to the grid information and extrusion deformation data at a starting moment of the current time step, and specifically include: determining whether any node in the geometric grid at the starting moment of the current time step is a boundary node to obtain a second determination result; the boundary node is a node at an edge of the geometric grid; if the second determination result is yes, determining that the deformation calculation method of the node / integration point in the current time step is a time-space stable node integration algorithm; if the second determination result is no, determining whether the time step is less than 100 to obtain a third determination result; if the third determination result is yes, determining that the deformation calculation method of the node / integration point in the current time step is the time-space stable node integration algorithm; if the third determination result is no, further determining whether the current time step number is an integer multiple of 100 to obtain a fourth determination result; if the fourth determination result is no, continuing to use a calculation method of a previous time step; if the fourth determination result is yes, further determining whether an algorithm of the previous time step is a node smoothed finite element method to obtain a fifth determination result; if the fifth determination result is yes, further determining whether stress is greater than a preset node average ratio to obtain a sixth determination result; if the fifth determination result is no, further determining whether stress is less than the preset node average ratio to obtain a seventh determination result; if the sixth determination result is yes, determining that the deformation calculation method of the node / integration point in the current time step is the time-space stable node integration algorithm; if the sixth determination result is no, determining that the deformation calculation method of the node / integration point in the current time step is the node smoothed finite element method; if the seventh determination result is yes, determining that the deformation calculation method of the node / integration point in the current time step is the node smoothed finite element method; if the seventh determination result is no, determining that the deformation calculation method of the node / integration point in the current time step is the time-space stable node integration algorithm; the extrusion deformation data includes stress, strain, displacement and acceleration; the integration point is an integration point used for numerical integration in the time-space stable node integration algorithm or the node smoothed finite element method; and the deformation calculation method is the time-space stable node integration algorithm or the node smoothed finite element algorithm; The deformation calculation module is configured to calculate extrusion deformation data of each node / integration point in a current time step according to object information of the target measured object in the current time step by using a corresponding deformation calculation method, wherein node data includes displacement and acceleration, and integration point data includes stress and strain. The end determination module is configured to determine whether an ending moment of the current time step is a termination moment of extrusion of the target measured object to obtain a first determination result. The first determination result module is configured to, if the first determination result is no, perform data updating according to extrusion deformation of each node / integration point at the ending moment of the current time step, and use an updating result as extrusion deformation data at a starting moment of a next time step. A second judgment result module is configured to, if the first judgment result is yes, determine the extrusion deformation state of the target measured object according to the extrusion deformation data of all nodes / integration points of the target measured object at all moments of extrusion.

6. An electronic device, comprising: The electronic device comprises a memory and a processor, the memory is used for storing a computer program, and the processor runs the computer program to enable the electronic device to perform the extrusion deformation state detection method according to any one of claims 1-4.

7. A computer readable storage medium characterized by The computer program is stored in the memory and is executed by the processor to implement the extrusion deformation state detection method according to any one of claims 1-4.

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