Method for predicting thermal residual stress of lattice structure reinforced composite material

Abstract

The invention discloses a method for predicting thermal residual stress of a lattice structure reinforced composite material, and belongs to the field of lattice structure lattice unit model design. The method specifically comprises the following steps: 1) establishing a tetrahedron model and a foundation beam model; (2) the foundation beam models are combined after being rotated, and the intersection part of the foundation beam models and the tetrahedron model is a 1 / 48 dot matrix unit model; 3) sequentially obtaining a 1 / 24 dot matrix unit model, a 1 / 8 dot matrix unit model and a complete dot matrix structure model; 4) establishing a cube model; subtracting the lattice structure model from the cubic model to obtain a matrix model; 5) obtaining a lattice structure reinforced composite material geometric model; and 6) performing numerical simulation on the thermal mismatch behavior in the cooling process of the geometric model of the lattice structure reinforced composite material to obtain the thermal residual stress distribution condition of the lattice structure reinforced composite material. The method is easy and convenient to operate, the constructed lattice structure models are rich, and the simulation precision is high.

Description

Technical Field

[0001] The present invention belongs to the field of lattice unit model design of lattice structures, and particularly relates to a method for predicting the thermal residual stress of lattice structure reinforced composites. Background Art

[0002] The thermal residual stress of lattice structure reinforced composites is a problem of great concern in engineering design. The geometric shape of the lattice structure has an important influence on the distribution of thermal residual stress. Usually, the experimental measurement method is used to qualitatively reflect the load transfer and two-phase deformation conditions. However, it is difficult to systematically and comprehensively measure the influence of lattice structures with different shapes on the stress-strain distribution and residual stress distribution of the system through experimental methods.

[0003] In recent years, finite element simulation technology has been increasingly applied in the simulation of the mechanical behavior of lattice structures, and relatively accurate performance prediction results have been obtained. A new modeling method for lattice units of lattice structures combined with finite element simulation technology is expected to realize the thermal shrinkage behavior and high-throughput calculation of lattice structures with different shapes, reveal the relationship between the shape of lattice units and the thermal residual stress distribution of lattice structure reinforced composites, meet the needs of scientific research work, and its calculation results are expected to guide the research and development of new structures in engineering applications. Summary of the Invention

[0004] The purpose of the present invention is to address the current situation of difficult modeling of the shape of lattice units in the prior art, and provide a method for predicting the thermal residual stress of lattice structure reinforced composites. The method provided by the present invention can create lattice structures of various shapes. With the help of finite element simulation technology, the thermal shrinkage behavior of lattice structure reinforced composites is predicted, and the thermal residual stress of the lattice structure is calculated.

[0005] The specific technical solution adopted by the present invention is as follows:

[0006] The present invention provides a method for predicting the thermal residual stress of lattice structure reinforced composites, and the specific steps are as follows:

[0007] S1: Create a tetrahedron model OABC in 3D drawing software. The vertex positions of the tetrahedron model OABC are: O(0, 0, 0), A(L, L, L), B(0, 0, L), C(0, L, L);

[0008] S2: Input the number of beams N and cross-sectional shape parameters in 3D drawing software to create a basic beam model; determine the positions of the beams;

[0009] S3: According to the number of beams N in the basic beam model in step S2, copy N basic beam models; each basic beam model is rotated and merged into a solid model; the intersecting part of the solid model and the tetrahedron model created in step S1 is a 1 / 48 lattice unit model;

[0010] S4: After mirror-symmetrizing the 1 / 48 dot matrix unit model obtained in step S3 with respect to the ACO plane, a 1 / 48 dot matrix unit mirror-symmetry model is obtained; the 1 / 48 dot matrix unit model and the 1 / 48 dot matrix unit mirror-symmetry model are combined to obtain a 1 / 24 dot matrix unit model;

[0011] S5: Duplicate two copies of the 1 / 24 dot matrix unit model obtained in step S4, rotate them respectively and then combine them to obtain a 1 / 8 dot matrix unit model;

[0012] S6: The 1 / 8 dot matrix unit model obtained in step S5 is mirror-symmetrized with respect to the XOY plane in the Cartesian coordinate system, combined and then mirror-symmetrized with respect to the YOZ plane, combined and then mirror-symmetrized with respect to the ZOX plane to obtain a complete dot matrix structure model;

[0013] S7: Establish a cube model with a side length of 2L; perform a volume subtraction operation in the modeling software to subtract the dot matrix structure model from the cube model to obtain a matrix model;

[0014] S8: Assemble the matrix model obtained in step S7 and the dot matrix structure model in step S6 to obtain a geometric model of a dot matrix structure reinforced composite material;

[0015] S9: Perform mesh division on the geometric model of the dot matrix structure reinforced composite material obtained in step S8, apply a cooling boundary condition, and input the material properties of the matrix model and the dot matrix structure model respectively; perform a numerical simulation on the thermal mismatch behavior during the cooling process of the geometric model of the dot matrix structure reinforced composite material to obtain the thermal residual stress distribution of the dot matrix structure reinforced composite material.

[0016] Preferably, the 3D drawing software uses AutoCAD, Blender, Rhino or Abaqus.

[0017] Preferably, in step S2, if the cross-sectional shape parameter is circular, input the cross-sectional radius; if the cross-sectional shape parameter is annular, input the inner diameter and outer diameter of the ring; if the cross-sectional shape parameter is polygonal, input the number of sides of the polygon and the radius of the circumscribed circle.

[0018] Preferably, in step S2, the position of the beam is determined as follows: It is stipulated that the starting point of each beam in the foundation beam model is at any vertex of the tetrahedron model OABC, the end point of the beam is on any side of the plane opposite to the vertex, and the offset value offset of the beam orientation ranges from [0, 1] to determine the position of the beam.

[0019] Preferably, the rotation mode of each basic beam model in step S3 is as follows: Obtain the direction vector Vn of the beam according to the starting point and the ending point of the beam, and normalize the direction vector Vn to obtain Vn'; Determine the rotation axis RotAxis = Vn'+(0, 0, 1); Use the centroid of the beam as the rotation center and rotate it 180° around the rotation axis RotAxis vector.

[0020] Preferably, after copying in step S5, a 1 / 24 first lattice unit model and a 1 / 24 second lattice unit model are obtained respectively; The 1 / 24 first lattice unit model rotates clockwise 120° around the (1, 1, 1) vector, and the 1 / 24 second lattice unit model rotates counterclockwise 120° around the (1, 1, 1) vector. After merging the two rotated 1 / 24 lattice unit models, a 1 / 8 lattice unit model is obtained.

[0021] Preferably, in step S7, the vertex coordinates of the cube model are (-L, -L, -L), (-L, -L, L), (-L, L, L), (-L, L, -L), (L, -L, -L), (L, -L, L), (L, L, L), (L, L, -L) respectively.

[0022] Preferably, in the mesh division in step S9, the mesh type is 4-node tetrahedral elements, and the total number of mesh elements is not less than 500,000.

[0023] Preferably, the cooling boundary condition setting in step S9: The high temperature T1 is not greater than 1600 °C, the low temperature T0 is not lower than -100 °C, and the cooling rate ΔT is 2 - 200 °C.

[0024] Preferably, in step S9, numerical simulation is carried out using finite element software such as ABAQUS, ANSYS or Comsol software.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The method provided by the present invention can generate lattice structures of various shapes. By flexibly setting the beam position parameters to control the shape of the lattice structure, the established lattice structure model has a rich shape and is close to the real lattice structure geometric model in industrial production, and has wide applicability.

[0027] (2) The modeling process in the present invention is convenient and simple to operate. Only a small number of parameters such as all faces, vertices and directions of the tetrahedron need to be controlled, which is convenient for users to operate.

[0028] (3) By calculating the thermal shrinkage behavior of the lattice structure, the distribution of internal participation stress and thermal shrinkage strain can be revealed, which has important significance academically and can also provide effective guidance for the structural design of industrial materials. Description of the Drawings

[0029] Figure 1 It is the 1 / 48 dot matrix unit model established in Examples 1 to 3;

[0030] Figure 2 It is the 1 / 24 dot matrix unit model established in Examples 1 to 3;

[0031] Figure 3 It is the 1 / 8 dot matrix unit model established in Examples 1 to 3;

[0032] Figure 4 It is the dot matrix unit model established in Examples 1 to 3;

[0033] Figure 5 It is the thermal residual stress simulation nephogram of the geometric model of the lattice structure reinforced composite material established in Examples 1 to 3. Detailed Implementation Modes

[0034] The present invention will be further described and explained below in conjunction with the drawings and specific implementation modes. The technical features of each implementation mode in the present invention can be combined correspondingly without conflict.

[0035] The present invention provides a method for predicting the thermal residual stress of a lattice structure reinforced composite material, and the specific steps of the operation are as follows:

[0036] 1. Create a tetrahedron model.

[0037] Create a tetrahedron model OABC in a three-dimensional drawing software. The vertex positions of the tetrahedron model OABC are: O(0, 0, 0), A(L, L, L), B(0, 0, L), C(0, L, L). The BOC plane of the tetrahedron model OABC is denoted as 0, the CAB plane is denoted as 1, the OBA plane is denoted as 2, and the ACO plane is denoted as 3.

[0038] 2. Create a basic beam model.

[0039] Input the number of beams N and cross-sectional shape parameters in a three-dimensional drawing software to create a basic beam model. If the cross-sectional shape parameter is circular, input the cross-sectional radius; if the cross-sectional shape parameter is annular, input the inner diameter and outer diameter of the ring; if the cross-sectional shape parameter is polygonal, input the number of sides of the polygon and the radius of the circumscribed circle.

[0040] 3. Determine the position of the beam.

[0041] It is stipulated that the starting point of each beam in the foundation beam model is at any vertex of the tetrahedron model OABC, and the ending point of the beam is on any side of the plane opposite to this vertex. If the starting point of the beam is at point A of the tetrahedron model OABC, the ending point of this beam is on side BC, side BO, or side CO of the BOC plane opposite to point A (such that this beam is in the ACO plane); if the starting point of the beam is at point B of the tetrahedron model OABC, the ending point of this beam is on side AC, side CO, or side AO of the ACO plane opposite to point B, and so on.

[0042] The offset value of the beam orientation offset, offset, ranges from [0, 1] to determine the position of the beam.

[0043] IV. Obtain the 1 / 48 lattice unit model.

[0044] (1) According to the number of beams N in the foundation beam model, copy N foundation beam models.

[0045] (2) Obtain the direction vector Vn of the beam based on the starting point and ending point of the beam, and normalize the direction vector Vn to obtain Vn', so that its vector length is 1.

[0046] (3) Determine the rotation axis RotAxis:

[0047] RotAxis = Vn′ + (0, 0, 1);

[0048] (4) Take the centroid of the beam as the rotation center and rotate it 180° around the RotAxis vector.

[0049] (5) After performing the above rotation on N foundation beam models, merge them into a solid model GEO; the intersection part of the solid model GEO and the tetrahedron model created in step one is the 1 / 48 lattice unit model.

[0050] V. Obtain the 1 / 24 lattice unit model.

[0051] After copying the 1 / 48 lattice unit model obtained in step four, perform mirror symmetry with the ACO plane to obtain the 1 / 48 lattice unit mirror symmetry model; merge the 1 / 48 lattice unit model and the 1 / 48 lattice unit mirror symmetry model to obtain the 1 / 24 lattice unit model.

[0052] VI. Obtain the 1 / 8 lattice unit model.

[0053] (1) Copy two copies of the 1 / 24 lattice unit model obtained in step five, and denote them as the 1 / 24 first lattice unit model and the 1 / 24 second lattice unit model respectively.

[0054] (2) Rotate the 1 / 24 first dot matrix unit model clockwise by 120° around the (1, 1, 1) vector, and rotate the 1 / 24 second dot matrix unit model counterclockwise by 120° around the (1, 1, 1) vector.

[0055] (3) Combine the two rotated 1 / 24 dot matrix unit models to obtain a 1 / 8 dot matrix unit model.

[0056] VII. Obtain a complete dot matrix structure model.

[0057] (1) Duplicate the 1 / 8 dot matrix unit model obtained in Step VI, make a mirror symmetry with respect to the XOY plane in the Cartesian coordinate system to obtain the Model_1_8_XOY model, and combine the 1 / 8 dot matrix unit model and the Model_1_8_XOY model to obtain the Model_1_8_1 model;

[0058] (2) Duplicate the Model_1_8_1 model, make a mirror symmetry with respect to the YOZ plane in the Cartesian coordinate system to obtain the Model_1_8_1_YOZ model; combine the Model_1_8_1 model and the Model_1_8_1_YOZ model to obtain the Model_1_8_2 model;

[0059] (3) Duplicate the Model_1_8_2 model, make a mirror symmetry with respect to the ZOX plane in the Cartesian coordinate system to obtain the Model_1_8_2_ZOX model; combine the Model_1_8_2 model and the Model_1_8_2_ZOX model to obtain a complete dot matrix structure model.

[0060] VIII. Establish a cube model.

[0061] Establish a cube model CUBIC with a side length of 2L; the vertex coordinates of the cube model CUBIC are (-L, -L, -L), (-L, -L, L), (-L, L, L), (-L, L, -L), (L, -L, -L), (L, -L, L), (L, L, L), and (L, L, -L) respectively.

[0062] IX. Subtraction operation of solid from solid.

[0063] In the modeling software, use the cube model CUBIC established in Step VIII as the object to be subtracted, and use the dot matrix structure model obtained in Step VII as the subtracting object, and subtract the dot matrix structure model from the cube model to obtain a matrix model.

[0064] X. Obtain a geometric model of a dot matrix structure reinforced composite material.

[0065] Assemble the matrix model obtained in Step IX and the dot matrix structure model in Step VII to obtain a geometric model of a dot matrix structure reinforced composite material.

[0066] XI. Numerical simulation.

[0067] Perform mesh generation on the geometric model of the lattice structure reinforced composite material obtained in Step X. In the mesh generation, the mesh type is 4-node tetrahedral elements, and the total number of mesh elements is not less than 500,000. Apply a cooling boundary condition: the high temperature T1 is not greater than 1600 °C, the low temperature T0 is not lower than -100 °C, and the cooling rate ΔT is 2 to 200 °C.

[0068] Input the material properties of the matrix model and the lattice structure model respectively; perform numerical simulation on the thermal mismatch behavior during the cooling process of the geometric model of the lattice structure reinforced composite material to obtain the thermal residual stress distribution of the lattice structure reinforced composite material.

[0069] In the present invention, the 3D drawing software uses AutoCAD, Blender, Rhino or Abaqus. The numerical simulation is carried out using finite element software such as ABAQUS, ANSYS or Comsol software.

[0070] Example 1

[0071] I. Create a tetrahedron OABC with the shortest side length of L for geometric parameters; the vertex positions of the tetrahedron model OABC are: O(0, 0, 0), A(L, L, L), B(0, 0, L), C(0, L, L).

[0072] II. Input the number of beams N = 2, and the cross-sectional shape parameter is a circle with a radius of 5, and create a basic beam model.

[0073] III. Determine that the plane parameter of the first beam is 0, the node number of the beam is 0, and the starting point PO 1 of the first beam is (0, 0, L). The offset of the beam orientation is 0.75, so the starting point PE 1 of the first beam is (0, 0.75L, 0.75L); determine that the plane parameter of the second beam is 1, the node number of the beam is 1, and the starting point PO 1 ' of the second beam is (L, L, L). The offset of the beam orientation is 0, so the end point PE 1 ' of the second beam is (0, 0, L).

[0074] IV. According to the number of two beams, copy 2 basic beam models, and perform the following operations on the 2 basic beam models respectively:

[0075] (1) Obtain the direction vector Vn of the beam according to the starting point and end point of the beam, and normalize the direction vector Vn to obtain Vn', so that its vector length is 1.

[0076] (2) Determine the rotation axis RotAxis:

[0077] RotAxis = Vn′+(0, 0, 1);

[0078] (3) Using the centroid of the beam as the center of rotation, rotate it 180° around the RotAxis vector.

[0079] (2) After performing the above rotation on both of the two basic beam models, merge them into a solid model GEO; the intersecting part of the solid model GEO and the tetrahedron model OABC created in the first step is a 1 / 48 lattice unit model, as Figure 1 (a) shown.

[0080] V. After copying the above 1 / 48 lattice unit model, perform mirror symmetry with the ACO plane to obtain a 1 / 48 lattice unit mirror symmetry model; merge the 1 / 48 lattice unit model and the 1 / 48 lattice unit mirror symmetry model to obtain a 1 / 24 lattice unit model, as Figure 2 (a) shown.

[0081] VI. Copy two copies of the above 1 / 24 lattice unit models, denoted as the 1 / 24 first lattice unit model and the 1 / 24 second lattice unit model respectively. Rotate the 1 / 24 first lattice unit model 120° clockwise around the (1, 1, 1) vector, and rotate the 1 / 24 second lattice unit model 120° counterclockwise around the (1, 1, 1) vector. After merging the two rotated 1 / 24 lattice unit models, obtain a 1 / 8 lattice unit model, as Figure 3 (a) shown.

[0082] VII. Obtain a complete lattice structure model.

[0083] (1) Copy one copy of the above 1 / 8 lattice unit model, perform mirror symmetry with the XOY plane in the Cartesian coordinate system to obtain the Model_1_8_XOY model, and after merging the 1 / 8 lattice unit model and the Model_1_8_XOY model, obtain the Model_1_8_1 model;

[0084] (2) Copy one copy of the Model_1_8_1 model, perform mirror symmetry with the YOZ plane in the Cartesian coordinate system to obtain the Model_1_8_1_YOZ model; after merging the Model_1_8_1 model and the Model_1_8_1_YOZ model, obtain the Model_1_8_2 model;

[0085] (3) Duplicate the Model_1_8_2 model and perform a mirror symmetry operation with respect to the ZOX plane in the Cartesian coordinate system to obtain the Model_1_8_2_ZOX model; after merging the Model_1_8_2 model and the Model_1_8_2_ZOX model, a complete lattice structure model is obtained.

[0086] VIII. Establish a cubic model CUBIC with a side length of 2L; the vertex coordinates of the cubic model CUBIC are (-L, -L, -L), (-L, -L, L), (-L, L, L), (-L, L, -L), (L, -L, -L), (L, -L, L), (L, L, L), and (L, L, -L) respectively.

[0087] IX. Perform a volume subtraction operation in the modeling software, using the cubic model CUBIC as the object to be subtracted and the lattice structure model as the subtracting object, and subtract the lattice structure model from the cubic model to obtain the matrix model.

[0088] X. Assemble the matrix model and the lattice structure model to obtain the geometric model of the lattice structure reinforced composite material, as shown in Figure 4 (a).

[0089] Example 2

[0090] The remaining steps of this example are the same as those of Example 1, except that the offsets of the two beams are different: determine that the plane parameters of the first beam are 0, the node numbers of the beam are 0, and the starting point PO 2 of the first beam is (0, 0, L). The offset of the beam orientation is 1, so the end point PE 2 of the first beam is (0, L, L); determine that the plane parameter of the second beam is 1, the node number of the beam is 1, and the starting point PO 2 ' of the second beam is (L, L, L). The offset of the beam orientation is 0, so the end point PE 2 ' of the second beam is (0, 0, L).

[0091] The 1 / 48 lattice unit model established in this example is shown in Figure 1 (b). The 1 / 24 lattice unit model is shown in Figure 2 (b). The 1 / 8 lattice unit model is shown in Figure 3 (b). The finally established geometric model of the lattice structure reinforced composite material is shown in Figure 4 (b).

[0092] Example 3

[0093] The remaining steps of this embodiment are the same as those of Embodiment 1, except that the offsets of the two beams are different: the plane parameters of the first beam are determined to be 0, the node number of the beam is 0, and the starting point PO of the first beam 3 is (0, 0, L). The offset of the beam orientation is 1, so the starting point PE of the first beam 3 is (0, L, L); the plane parameters of the second beam are determined to be 1, the node number of the beam is 1, and the starting point PO of the second beam 3 ’ are L, L, L) respectively. The offset of the beam orientation is 1, so the end point PE of the second beam 3 ’ is (0, L, L).

[0094] The 1 / 48 lattice unit model established in this embodiment is as shown in Figure 1 (c). The 1 / 24 lattice unit model is as shown in Figure 2 (c). The 1 / 8 lattice unit model is as shown in Figure 3 (c). Finally, the geometric model of the lattice structure reinforced composite material is established, as shown in Figure 4 (c).

[0095] Next, the geometric models of the lattice structure reinforced composite materials established in Embodiments 1 to 3 are respectively predicted for the thermal residual stress distribution, as follows:

[0096] (1) The three-dimensional meshes are respectively divided for the geometric models of the lattice structure reinforced composite materials. The mesh type is a 4-node tetrahedral mesh, and the number of divided meshes is about 880,000.

[0097] (2) Set the cooling boundary conditions, set the high temperature T1 = 500 °C, the low temperature T0 = 20 °C, and the cooling rate ΔT = 10 °C.

[0098] (3) Use the commercial finite element software ABAQUS to input the material properties: the material of the matrix model is pure aluminum (Al), and the material of the lattice structure model is silicon carbide (SiC). The Poisson's ratio is not sensitive to temperature, 0.33 for aluminum and 0.17 for silicon carbide. The Young's modulus (E Al , unit GPa) varies with temperature (T) as follows:

[0099] E Al = 68.93 + 0.017T - 3.97×10 -4 T 2 + 4.28×10 -7 T 3

[0100] The thermal expansion coefficient (α Al , unit 10 -6 / K) varies with temperature (T) as follows:

[0101] α Al = (21.98 + 0.017T - 1.89×10 -5 T 2 + 5.30×10 -9 T 3 )

[0102] The Young's modulus (E SiC , in GPa) of silicon carbide varies with temperature (T) as follows:

[0103] E Al = 427.48 - 0.025T + 1.58×10 -6 T 2 - 2.00×10 -9 T 3

[0104] The coefficient of thermal expansion (α SiC , in 10 -6 / K) of silicon carbide varies with temperature (T) as follows:

[0105] α Al = (3.07 + 0.006T - 5.85×10 -6 T 2 + 2.07×10 -9 T 3 )

[0106] Numerical simulation was carried out on the thermal mismatch behavior of the lattice structure reinforced composite material during the cooling process to obtain the distribution of thermal residual stress of the lattice structure reinforced composite material.

[0107] In this embodiment, three geometric models of lattice structure reinforced composite materials were established. The lattice structure is relatively complex. Figure 5 The sectional views of the residual stress distribution of the matrix are at X = 0 (Figs. (a), (c), (e)) and X = 50 (Figs. (b), (d), (f)). It can be found that the thermal residual stress distribution of the composite material has been well predicted. In the aluminum matrix near the silicon carbide lattice, there is a relatively high thermal residual stress. However, by comparing the residual stress sectional views, it can be found that in the first lattice structure, there are extremely low stress regions and extremely high stress strip patterns inside the aluminum matrix far from the silicon carbide. While the second and third models do not have this feature, only low stress regions exist in the matrix far from the silicon carbide. It can be seen that the method provided by the present invention for establishing the model can effectively predict the thermal residual stress distribution of the lattice structure reinforced composite material with a complex structure.

[0108] The embodiments described above are only a preferred solution of the present invention, but they are not intended to limit the present invention. Those of ordinary skill in the relevant technical field can still make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A method for predicting thermal residual stress of a lattice structure reinforced composite material, characterized in that: The specific steps are as follows: S1: Create a tetrahedron model OABC in a three-dimensional mapping software. The vertex positions of the tetrahedron model OABC are: O(0, 0, 0), A(L, L, L), B(0, 0, L), and C(0, L, L); S2: Input the number of beams N and the cross-sectional shape parameters in the 3D drawing software to create a basic beam model; determine the position of the beam; S3: according to the number of beams N in the foundation beam model in step S2, N foundation beam models are copied; each foundation beam model is rotated and merged into a solid model; the intersection of the solid model and the tetrahedron model created in step S1 is a 1 / 48 lattice unit model; S4: After the 1 / 48 lattice unit model obtained in step S3 is mirror-symmetric with the ACO plane, a 1 / 48 lattice unit mirror-symmetric model is obtained; the 1 / 48 lattice unit model and the 1 / 48 lattice unit mirror-symmetric model are combined to obtain a 1 / 24 lattice unit model; S5: Copy two copies of the 1 / 24 lattice unit model obtained in step S4, rotate them respectively, and then merge them to obtain a 1 / 8 lattice unit model; S6: The 1 / 8 lattice unit model obtained in step S5 is mirror-symmetric with the XOY plane in the Cartesian coordinate system, and then mirror-symmetric with the YOZ plane after merging, and then mirror-symmetric with the ZOX plane after merging, to obtain a complete lattice structure model; S7: Establish a cube model with a side length of 2L; perform a volume subtraction operation in the modeling software to subtract the lattice structure model from the cube model to obtain a matrix model; S8: Assembling the matrix model obtained in step S7 and the lattice structure model obtained in step S6 to obtain a geometric model of the lattice structure reinforced composite material; S9: Meshing the geometric model of the lattice structure reinforced composite material obtained in step S8, applying a cooling boundary condition, and inputting material properties of the matrix model and the lattice structure model respectively; The thermal mismatch behavior of the lattice structure reinforced composite material geometric model during the cooling process was numerically simulated to obtain the thermal residual stress distribution of the lattice structure reinforced composite material.

2. The method for predicting thermal residual stress of a lattice structure reinforced composite material according to claim 1, characterized in that: The three-dimensional drawing software adopts AutoCAD, Blender, Rhino or Abaqus.

3. The method for predicting thermal residual stress of lattice structure reinforced composite material according to claim 1, characterized in that: In step S2, if the cross-sectional shape parameter is a circle, input the cross-sectional radius; if the cross-sectional shape parameter is a ring, input the inner diameter and outer diameter of the ring; if the cross-sectional shape parameter is a polygon, input the number of sides of the polygon and the radius of the circumscribed circle.

4. The method for predicting thermal residual stress of lattice structure reinforced composite material according to claim 1, characterized in that: In step S2, the beam position is determined as follows: the starting point of each beam in the basic beam model is specified to be at any vertex of the tetrahedron model OABC, the end point of the beam is on any side of the plane opposite to the vertex, the offset of the beam orientation has a value range of [0, 1], and the position of the beam is determined.

5. The method for predicting thermal residual stress of lattice structure reinforced composite material according to claim 1, characterized in that: The rotation method of each basic beam model in step S3 is as follows: obtain the direction vector Vn of the beam according to the starting point and end point of the beam, and normalize the direction vector Vn to obtain Vn'; determine the rotation axis RotAxis = Vn'+(0, 0, 1); use the centroid of the beam as the rotation center and rotate it 180° around the rotation axis RotAxis vector.

6. The method for predicting thermal residual stress of a lattice structure reinforced composite material according to claim 1, characterized in that: After copying in step S5, a 1 / 24 first lattice unit model and a 1 / 24 second lattice unit model are obtained respectively; the 1 / 24 first lattice unit model is rotated 120° clockwise around the (1, 1, 1) vector, and the 1 / 24 second lattice unit model is rotated 120° counterclockwise around the (1, 1, 1) vector. The two rotated 1 / 24 lattice unit models are merged to obtain a 1 / 8 lattice unit model.

7. The method for predicting thermal residual stress of a lattice structure reinforced composite material according to claim 1, characterized in that: In step S7, the coordinates of the vertices of the cube model are (-L, -L, -L), (-L, -L, L), (-L, L, L), (-L, L, -L), (L, -L, -L), (L, -L, L), (L, L, L), (L, L, -L).

8. The method for predicting thermal residual stress of a lattice structure reinforced composite material according to claim 1, characterized in that: In the mesh division in step S9, the mesh type is 4-node tetrahedron unit, and the total number of mesh units is not less than 500,000.

9. The method for predicting thermal residual stress of a lattice structure reinforced composite material according to claim 1, characterized in that: The cooling boundary conditions in step S9 are set as follows: the high temperature T1 is not greater than 1600°C, the low temperature T0 is not less than -100°C, and the cooling rate ΔT is 2 to 200°C.

10. The method for predicting thermal residual stress of a lattice structure reinforced composite material according to claim 1, characterized in that: In step S9, finite element software ABAQUS, ANSYS or Comsol software is used to perform numerical simulation.

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