A stress-strain analysis method for an anisotropic material

Abstract

The application provides a stress-strain analysis method of an anisotropic material, characterized in that the method comprises the following steps: S1, establishing a geometric model of the anisotropic material, and performing mesh division on the geometric model to obtain an isolated mesh model; S2, processing each mesh unit in the isolated mesh model to obtain a directional vector of each mesh unit; S3, creating a discrete field by using the directional vector of each mesh unit of the isolated mesh model obtained in step S2; and S4, performing material coordinate paving on each mesh unit of the isolated mesh model by using the discrete field.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of stress-strain analysis of anisotropic materials, and in particular to a method for mapping isolated grid coordinates of anisotropic materials. BACKGROUND

[0002] Ceramic materials belong to anisotropic materials, and have the characteristics of high temperature resistance, low density, corrosion resistance, high hardness, etc., and are widely used in devices such as aircraft engines, for example, flame tubes, turbine guide vanes, turbine outer rings, tail nozzles, etc. However, due to the stringent requirements of aircraft engines on their performance and stability, it is necessary to analyze the stress and strain of these anisotropic materials.

[0003] The existing stress-strain analysis method for anisotropic materials including ceramic matrix composites, etc. cannot consider both grid quality and element coordinate laying when establishing a grid model, thereby limiting the grid quality. The discrete method used in the prior art lays element coordinates in the grid model, which makes it difficult to select surfaces and lines due to grid discretization, thereby making it difficult to determine the material direction when designing complex grid element layups. The above factors result in inaccurate and inaccurate stress-strain analysis of ceramic matrix composites, making it difficult to fully guarantee the performance and stability of ceramic composite parts and other anisotropic materials, and failing to meet the demand for stress-strain analysis of anisotropic materials in the field.

[0004] Therefore, a method for better stress-strain analysis of anisotropic materials is needed to improve the performance and stability of anisotropic material parts. SUMMARY

[0005] In order to solve the problems and defects in the prior art, the present application provides a method for stress-strain analysis of anisotropic materials, which uses an isolated grid coordinate mapping method to establish a model, which can realize element coordinate laying for parts with complex layup design, and further analyze the stress and strain of anisotropic materials.

[0006] According to one embodiment of the present application, a method for stress-strain analysis of anisotropic materials is provided, which comprises the following steps: S1 establishing a geometric model of anisotropic materials and dividing the geometric model into grids to obtain an isolated grid model; S2 processing each grid element in the isolated grid model to obtain a direction vector of each grid element; S3 creating a discrete domain using the direction vector of each grid element of the isolated grid model obtained in step S2; S4 laying material coordinates for each grid element of the isolated grid model using the discrete domain.

[0007] Optionally, according to another embodiment of the present application, the step S2 further comprises the following steps: S2-1 obtaining the coordinates of the center point of each grid cell in the isolated grid model; S2-2 obtaining the tangent vector v1 at the projection point on the geometric line and the normal vector v3 at the projection point on the geometric surface of the center point of each grid cell in the isolated grid model; S2-3 keeping the v1 of the grid cell unchanged and correcting the v3 so that the v1 is perpendicular to the v3; S2-4 obtaining the v2 based on the v1 and the v3 by the right-hand rule, thereby obtaining the three directional vectors of the grid cell.

[0008] Optionally, according to another embodiment of the present application, the step S2-1 comprises: taking the average of all node coordinates of the grid cell as the center point coordinate of the grid cell.

[0009] Optionally, according to another embodiment of the present application, the step S2 uses Abaqus to process the grid cells in the isolated grid model to obtain the directional vectors of each grid cell.

[0010] Optionally, according to another embodiment of the present application, the step S2-2 comprises: using the getCurvature function in Abaqus to obtain the tangent vector v1 at the projection point on the geometric line of the center point of the grid cell, and using the Getnormal function to obtain the normal vector v3 at the projection point on the geometric surface of the center point of the grid cell.

[0011] Optionally, according to another embodiment of the present application, the step S2-3 comprises: taking the correction vector with the smallest coordinate change as the final normal axis direction.

[0012] Optionally, according to another embodiment of the present application, a stress-strain analysis method of anisotropic material is provided, characterized by comprising the following steps: establishing a geometric model of anisotropic material, and performing grid division on the geometric model to obtain an isolated grid model; for each grid cell in the isolated grid model, processing to obtain the coordinates of the center point C of each grid cell; obtaining the tangent vector v1 at the projection point on the geometric line and the normal vector v3 at the projection point on the geometric surface of the center point C of each grid cell in the isolated grid model; keeping the v1 of the tangent vector of the center point C of the grid cell at the projection point on the geometric line unchanged, and correcting the normal vector v3 of the center point C of the grid cell at the projection point on the geometric surface so that the v1 is perpendicular to the v3; obtaining the unit vector v2 based on the v1 and the v3 by the right-hand rule, thereby obtaining the three directional vectors of the grid cell; using the obtained directional vectors of each grid cell of the isolated grid model to create a discrete domain; and using the discrete domain to perform material coordinate paving for each grid cell of the isolated grid model.

[0013] Optionally, according to another embodiment of the present application, the step of obtaining the coordinates of the center point C of each grid unit comprises taking the average of all the node coordinates of the grid unit as the coordinates of the center point of the grid unit.

[0014] Optionally, according to another embodiment of the present application, the step of modifying the normal vector v3 of the center point C of the grid unit at the projection point on the geometric surface comprises taking the modified vector with the minimum coordinate change as the final normal axis direction.

[0015] According to another embodiment of the present application, a stress-strain analysis method of an anisotropic material is provided, which comprises the following steps:

[0016] S1, a geometric model of an anisotropic material is established, and the geometric model is meshed to obtain an isolated grid model;

[0017] S2, the isolated grid model is imported into Abaqus;

[0018] S3, the geometric model of the anisotropic material is imported into Abaqus and placed in the same model (Model) as the isolated grid model;

[0019] S4, for each grid unit in the isolated grid, the following processing is performed on the grid unit in the isolated grid model using Abaqus to obtain the directional vector of each grid unit:

[0020] S4-1, the coordinates of the center point of the grid unit are obtained;

[0021] S4-2, the tangent vector v1 of the center point of the grid unit at the projection point on the geometric line and the normal vector v3 of the center point of the grid unit at the projection point on the geometric surface are obtained, wherein as shown in Figure 2 , C point is the center point of a unit, E point is the projection point of C point on the curve L(x, y, z), vt is the directional vector of the tangent of the curve L(x, y, z) at the point E, and the tangent vector is taken as the 1 direction of the material attribute (as shown in Figure 3 ), Q point is the projection point of C point on the surface S(x, y, z), the gray plane is the tangent plane of the surface S(x, y, z) at the point Q, and vn is the directional vector of the normal of the surface S(x, y, z) at the point Q, and the normal vector is taken as the 3 direction of the material attribute (as shown in Figure 4 ).

[0022] S4-3, v1 is unchanged, and v3 is modified so that v1 is perpendicular to v3;

[0023] S4-4, based on v1 and v3, v2 is obtained through the right-hand rule, so as to obtain three directional vectors of the grid unit, v1, v2, and v3 are the material coordinate system of the grid unit;

[0024] S5 creating a discrete domain with the directional vector of each grid cell obtained in step S4;

[0025] S6 performing material coordinate laying for each grid cell with the discrete domain.

[0026] Optionally, in the above step S1, the geometric model of the anisotropic material is meshed by a CAE application system Hypermesh.

[0027] Optionally, in the S4-1, the average of all node coordinates of the grid cell is taken as the center point coordinate of the grid cell.

[0028] Optionally, in the S4-2, in Abaqus, the tangent vector v1 is obtained by using the getCurvature function, and the normal vector v3 is obtained by using the Getnormal function.

[0029] Optionally, in the S4-3, the corrected vector with the smallest coordinate change is taken as the final normal axis direction.

[0030] Compared with the prior art, the stress and strain analysis method of the anisotropic material provided by the embodiment of the present application has at least the following beneficial effects and advantages: the cell coordinate laying efficiency is improved; the cell coordinate laying is realized for a part with a complex laying design by taking geometry as a tool; the method is suitable for isolated grid models, the grid quality of the model is improved, and the strength calculation precision is improved; the material direction is determined, and the consistency and accuracy of the material direction are ensured; the stress and strain analysis accuracy and precision of the anisotropic material such as ceramic matrix composite material are improved, and the performance and stability of the anisotropic material part are fully ensured. BRIEF DESCRIPTION OF DRAWINGS

[0031] The present application can be better understood by reference to the accompanying drawings. The components in the drawings should not be considered as being to scale, emphasis instead being placed upon illustrating the principles of the application.

[0032] Figure 1 A flowchart of the stress and strain analysis method of the anisotropic material provided by the embodiment of the present application is shown.

[0033] Figure 2 A schematic diagram of determining the coordinate of the material of an isolated grid cell in the stress and strain analysis method of the anisotropic material provided by the embodiment of the present application is shown.

[0034] Figure 3 A schematic diagram of determining the tangent vector of the center point C of the grid cell with respect to the curve L in the stress and strain analysis method of the anisotropic material provided by the embodiment of the present application is shown.

[0035] Figure 4A schematic diagram for determining a normal vector of a mesh cell center point C with respect to a curved surface S in a stress-strain analysis method of an anisotropic material according to an embodiment of the present application.

[0036] Figure 5 A schematic diagram for determining an isolated mesh material coordinate using a geometric model in an exemplary embodiment of a stress-strain analysis method of an anisotropic material according to an embodiment of the present application.

[0037] Figure 6 A schematic diagram for determining a material principal direction in an exemplary embodiment of a stress-strain analysis method of an anisotropic material according to an embodiment of the present application.

[0038] Figure 7 A schematic diagram for determining a material normal in an exemplary embodiment of a stress-strain analysis method of an anisotropic material according to an embodiment of the present application.

[0039] Figure 8 A schematic diagram for applying corresponding boundary conditions and loads in an exemplary embodiment of a stress-strain analysis method of an anisotropic material according to an embodiment of the present application.

[0040] Figure 9 A schematic diagram for obtaining a stress-strain distribution of an anisotropic material in an exemplary embodiment of a stress-strain analysis method of an anisotropic material according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] Exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is to be understood that the present disclosure can be embodied in various forms without being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. It should be noted that technical terms or scientific terms used in the present disclosure should be interpreted as having the meanings commonly understood by those skilled in the art unless otherwise defined.

[0042] A stress-strain analysis method of an anisotropic material according to an embodiment of the present application will be described in detail below with reference to the accompanying drawings. Figure 1 A flowchart of a stress-strain analysis method of an anisotropic material according to an embodiment of the present application. Reference is made to Figure 1A stress-strain analysis method of an anisotropic material, characterized by comprising the following steps: establishing a geometric model of the anisotropic material, and performing meshing on the geometric model to obtain an isolated mesh model; for each mesh element in the isolated mesh model, processing to obtain the coordinates of the center point C of each mesh element; obtaining the tangent vector v1 at the projection point on a geometric line and the normal vector v3 at the projection point on a geometric surface of the center point C of each mesh element in the isolated mesh model; keeping the tangent vector v1 at the projection point on the geometric line unchanged, and correcting the normal vector v3 at the projection point on the geometric surface of the center point C of the mesh element, so that v1 is perpendicular to v3; on the basis of v1 and v3, obtaining v2 through the right-hand rule, so as to obtain three directional vectors of the mesh element; using the directional vectors of each mesh element of the obtained isolated mesh model to create a discrete domain; and using the discrete domain to perform material coordinate paving for each mesh element of the isolated mesh model.

[0043] The stress-strain analysis method of an anisotropic material according to another embodiment of the present application is described in detail below. Figure 1 The flowchart of the stress-strain analysis method of an anisotropic material according to the embodiment of the present application is shown. Figure 2 The schematic diagram of determining the coordinates of the material of the isolated mesh element in the stress-strain analysis method of an anisotropic material according to the embodiment of the present application is shown. Figure 3 The schematic diagram of determining the tangent vector of the center point C of the mesh element with respect to the curve L in the stress-strain analysis method of an anisotropic material according to the embodiment of the present application is shown. Figure 4 The schematic diagram of determining the normal vector of the center point C of the mesh element with respect to the surface S in the stress-strain analysis method of an anisotropic material according to the embodiment of the present application is shown.

[0044] Reference Figures 1-4 According to one embodiment of the present application, a stress-strain analysis method of an anisotropic material is provided, comprising the following steps: S1 establishing a geometric model of the anisotropic material, and performing meshing on the geometric model to obtain an isolated mesh model; S2 for each mesh element in the isolated mesh model, processing to obtain the directional vector of each mesh element; S3 using the directional vector of each mesh element of the isolated mesh model obtained in step S2 to create a discrete domain; and S4 using the discrete domain to perform material coordinate paving for each mesh element of the isolated mesh model. Optionally, in the above step S1, the geometric model of the anisotropic material can be established through a 3D model established by any modeling software, such as UG, Solidwork, etc.

[0045] Optionally, in the step S1, the geometric model of the anisotropic material can be meshed by a CAE application system, such as Hypermesh. The Hypermesh is a CAE application system.

[0046] Optionally, in the step S2, an engineering simulation system based on the finite element method, such as Abaqus, can be used to obtain the direction vectors of each mesh element.

[0047] According to another embodiment of the present application, the step S2 further comprises the following steps: S2-1 obtaining the coordinates of the center point of each mesh element in the isolated mesh model; S2-2 obtaining the tangent vector v1 at the projection point on the geometric line and the normal vector v3 at the projection point on the geometric surface of the center point of each mesh element in the isolated mesh model; S2-3 correcting v3 so that v1 is perpendicular to v3; S2-4 obtaining the unit vector v2 based on v1 and v3 by the right-hand rule, thereby obtaining the three direction vectors of the mesh element. Wherein, v1, v2, v3 are the material coordinate system of the mesh element. Specifically, when using Abaqus to obtain the direction vectors of each mesh element, the obtained isolated mesh model can be first imported into Abaqus, the geometric model of the anisotropic material is imported into Abaqus and placed in the same Model (model) as the isolated mesh model, and then the direction vectors of each mesh element are obtained by processing. The Abaqus mentioned here is an engineering simulation system based on the finite element method. A specific illustrative example is shown in FIG. 2. Figure 2 As shown in FIG. 2, C is the center point of a certain element. As shown in FIG. 3, Figure 3 As shown in FIG. 3, E is the projection point of C on the curve L(x, y, z), and vt is the tangent direction vector of the curve L(x, y, z) at the point E. The tangent vector is taken as the 1 direction of the material property. As shown in FIG. 4, Figure 4 As shown in FIG. 4, Q is the projection point of C on the surface S(x, y, z), and the gray plane is the tangent plane of the surface S(x, y, z) at the point Q. vn is the normal direction vector of the surface S(x, y, z) at the point Q. The normal vector is taken as the 3 direction of the material property. Wherein, in this example, vt is equivalent to v1 as described above, and vn is equivalent to v3 as described above. Optionally, the step of obtaining the direction vectors of each mesh element can be performed in an engineering simulation system based on the finite element method, such as Abaqus.

[0048] In the optional embodiment, the step S2-1 of obtaining the coordinates of the center point C of each mesh element in the isolated mesh model can be performed by taking the average of all node coordinates of the mesh element as the center point coordinate of the mesh element.

[0049] Optionally, in step S2-2, the tangent vector v1 of the center point of the grid element at the projection point on the geometric line can be obtained using the getCurvature function in Abaqus, and the normal vector v3 of the center point of the grid element at the projection point on the geometric surface can be obtained using the Getnormal function.

[0050] Optionally, in the step S2-3, the normal vector v3 of the center point of the grid element at the projection point on the geometric surface can be corrected by taking the correction vector with the minimum coordinate change as the final normal axis direction. That is, v3 is corrected to be strictly perpendicular to v1, and the corrected direction is the final normal axis direction. Through this step, the accuracy and precision of the analysis result can be advantageously improved. Optionally, the above steps S2-1, S2-2, S2-3 can be performed in an engineering simulation system based on the finite element method, such as Abaqus.

[0051] Through the above method and steps of the stress-strain analysis method of anisotropic material provided by the embodiments of the present application, the problem of difficulty in selecting the surface and line of anisotropic material is solved, and the material direction is more accurately determined when performing complex grid element layer design.

[0052] Optionally, the direction vector of each grid element of the isolated grid model obtained in step S2 is used to create a discrete domain in step S3, which can be achieved by writing the material coordinate system v1, v2 of each grid element into the discrete domain. Optionally, this can be performed in an engineering simulation system based on the finite element method, such as Abaqus.

[0053] Optionally, when using Abaqus for numerical analysis, the node, grid, material, and other information in the inp file is read for numerical solution. Similarly, when the element coordinates of the isolated grid are written into the inp file in a certain format, the element coordinate laying can be achieved. In Abaqus, a discrete domain is established, and each element number in the discrete domain corresponds to 6 input values. Since in the Cartesian coordinate system, only two directions of each element need to be determined to determine the element material coordinates, each direction is determined by 3 coordinates, so 6 values of each element are needed to determine the element material coordinates. Similarly, this conforms to the writing rules of the element coordinates in the inp file. Therefore, the element coordinates can be written into the inp file through the discrete domain.

[0054] The following describes exemplary embodiments of the stress-strain analysis method of anisotropic material provided by the embodiments of the present application in detail, so as to better understand the present application. Figure 5 The schematic diagram for determining the isolated grid material coordinates using geometric figures in the exemplary embodiments of the stress-strain analysis method of anisotropic material provided by the embodiments of the present application is shown in the following.Figure 6 A schematic diagram of determining the principal direction of a material in an exemplary embodiment of the stress-strain analysis method of an anisotropic material provided for applying the embodiments of the present application. Figure 7 A schematic diagram of determining the normal direction of a material in an exemplary embodiment of the stress-strain analysis method of an anisotropic material provided for applying the embodiments of the present application. Figure 8 A schematic diagram of applying corresponding boundary conditions and loads in an exemplary embodiment of the stress-strain analysis method of an anisotropic material provided for applying the embodiments of the present application. Figure 9 A schematic diagram of the stress-strain distribution of an anisotropic material obtained in an exemplary embodiment of the stress-strain analysis method of an anisotropic material provided for applying the embodiments of the present application.

[0055] Embodiment 1

[0056] In this exemplary embodiment, a stress-strain analysis is performed on a component of a ceramic matrix composite material using the stress-strain analysis method of an anisotropic material provided according to the embodiments of the present application. First, a geometric model of the component of the ceramic matrix composite material is established, and the geometric model is imported into Hypermesh for meshing to obtain an isolated mesh model.

[0057] As shown in FIG. 1, the isolated mesh model is imported into Abaqus. Then, the geometric model is imported into Abaqus and placed in the same model as the isolated mesh model. Figure 5

[0058] Next, material parameters and / or material directions are added to the isolated mesh model. This step more specifically includes obtaining coordinates of a center point of each mesh element in the isolated mesh model; as shown in FIG. 2, selecting a line as a material principal direction and a plane as a material normal direction to obtain a tangent vector at a projection point of the center point of each mesh element in the isolated mesh model on the geometric line and a normal vector at a projection point of the center point on the geometric plane; keeping v1 of the mesh element unchanged, correcting v3 so that v1 is perpendicular to v3; and obtaining v2 based on v1 and v3 by a right-hand rule to obtain three direction vectors of the mesh element. Optionally, a plug-in of Abaqus can be used to add material directions in this step. Figure 6 Figure 7 As shown in FIG. 3, according to the obtained analysis results of the component of the ceramic matrix material, corresponding boundary conditions and loads are applied to the component of the ceramic matrix material.

[0059] As shown in FIG. 4, according to the obtained analysis results of the component of the ceramic matrix material, corresponding boundary conditions and loads are applied to the component of the ceramic matrix material. Figure 8 As shown in FIG. 5, the stress-strain distribution of the ceramic matrix material is obtained.

[0060] Figure 9 ​​​The analysis result is submitted, and a stress-strain distribution diagram of the ceramic matrix material part after corresponding boundary conditions and loads are applied to the ceramic matrix material part is obtained. The stress-strain distribution diagram can be used for subsequent further judgment and analysis as needed.

[0061] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0062] It should be understood that the foregoing merely illustrates some embodiments, and changes, modifications, additions and / or changes can be made without departing from the scope and spirit of the disclosed embodiments, and the embodiments are illustrative rather than limiting. In addition, the described embodiments relate to currently considered most practical and most preferred embodiments, which should be understood as the embodiments should not be limited to the disclosed embodiments, but rather, are intended to cover different modifications and equivalent arrangements included in the spirit and scope of the embodiments. In addition, various embodiments described above can be applied together with other embodiments, for example, aspects of one embodiment can be combined with aspects of another embodiment to achieve another embodiment. In addition, each independent feature or component of any given component can constitute another embodiment.

[0063] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application.

Claims

1. A method for stress-strain analysis of anisotropic materials, characterized in that, The model is built using the isolated grid coordinate mapping method, including the following steps: S1 imports the isolated mesh model into Abaqus, establishes a 3D geometric model of the anisotropic material using modeling software, imports the 3D geometric model of the anisotropic material into Abaqus, places it in the same model as the isolated mesh model, and meshes the 3D geometric model to obtain a 3D isolated mesh model. S2 uses Abaqus to process each mesh cell in the 3D isolated mesh model to obtain the three-dimensional orientation vector of each mesh cell; S3 uses the orientation vector of each mesh element of the isolated mesh model obtained in step S2 to create a discrete domain in Abaqus; where each mesh element uses 6 values ​​to determine the material coordinates of the mesh element, where each orientation vector of the mesh element includes 3 coordinates, and the 6 values ​​are a total of 6 coordinates of the two orientation vectors of the mesh element; S4 uses a discrete domain to lay out the material coordinates for each mesh cell of the 3D isolated mesh model; wherein, the material coordinates of the mesh cells are written into the inp file to realize the laying out of the material coordinates of the mesh cells; S2 further includes the following steps: S2-1 Obtain the coordinates of the center point of each grid cell in the isolated grid model; S2-2 In Abaqus, the getCurvature function is used to obtain the tangent vector v1 at the projection point of the center point of each mesh cell on the geometric line in the 3D isolated mesh model, and the Getnormal function is used to obtain the normal vector v3 at the projection point of the center point of each mesh cell on the geometric surface. S2-3 Keep the v1 of the grid cell unchanged, and modify v3 so that v1 is perpendicular to v3; Based on v1 and v3, S2-4 obtains the unit vector v2 through the right-hand rule, thus obtaining the three direction vectors of the mesh element. The tangent vector v1, the unit vector v2, and the normal vector v3 form the material coordinate system of the mesh element. S2-3 includes: taking the correction vector with the smallest coordinate change as the final normal axis direction.

2. The stress-strain analysis method for anisotropic materials according to claim 1, characterized in that, Step S2-1 includes: The average value of the coordinates of all nodes in the grid cell is used as the coordinates of the center point of the grid cell.

3. A method for stress-strain analysis of anisotropic materials, characterized in that, The model is built using the isolated grid coordinate mapping method, including the following steps: Import the isolated mesh model into Abaqus, create a 3D geometric model of the ceramic matrix composite component using modeling software, import the 3D geometric model of the ceramic matrix composite component into Abaqus, place it in the same model as the isolated mesh model, and mesh the 3D geometric model to obtain a 3D isolated mesh model. Abaqus was used to process each mesh cell in the 3D isolated mesh model to obtain the coordinates of the center point C of each mesh cell; In Abaqus, the getCurvature function is used to obtain the tangent vector v1 at the projection point of the center point C of each mesh cell on the geometric line in the 3D isolated mesh model, and the Getnormal function is used to obtain the normal vector v3 at the projection point of the center point of each mesh cell on the geometric surface. Keep the tangent vector v1 of the center point C of the grid cell at the projection point on the geometric line unchanged, and modify the normal vector v3 of the center point C of the grid cell at the projection point on the geometric surface so that v1 is perpendicular to v3. Based on v1 and v3, the unit vector v2 is obtained by the right-hand rule, thus obtaining the three direction vectors of the mesh element. The tangent vector v1, the unit vector v2, and the normal vector v3 form the material coordinate system of the mesh element. A discrete domain is created using the orientation vector of each mesh cell in the obtained 3D isolated mesh model; where each mesh cell uses 6 values ​​to determine the material coordinates of the mesh cell, and each orientation vector of the mesh cell includes 3 coordinates, and the 6 values ​​are a total of 6 coordinates from the two orientation vectors of the mesh cell; Material coordinates are laid out for each mesh cell of the 3D isolated mesh model using a discrete domain; wherein, the material coordinates of the mesh cells are written into an inp file to realize the material coordinate laying out of the mesh cells. The steps to correct the normal vector v3 at the projection point of the center point C of the mesh cell onto the geometric surface include taking the correction vector with the smallest coordinate change as the final normal axis direction.

4. The stress-strain analysis method for anisotropic materials according to claim 3, characterized in that, The step of obtaining the coordinates of the center point C of each grid cell includes using the average of the coordinates of all nodes in the grid cell as the coordinates of the center point of the grid cell.

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