A method for predicting thermal residual stress in discontinuous particle reinforced composites

Abstract

The present invention discloses a method for predicting thermal residual stress of discontinuous particle reinforced composite materials, which belongs to the field of new composite material modeling. Specifically as follows: 1) construct an initial convex polyhedron reinforcement phase particle model; 2) establish a composite material basic model; 3) perform volume scaling on the above-mentioned initial convex polyhedron reinforcement phase particle model to obtain N target convex polyhedron reinforcement phase particle models; 4) rotate and translate each target convex polyhedron reinforcement phase particle model in space and combine it with the composite material basic model to obtain a discontinuous particle reinforced composite material model; 5) perform grid division, apply cooling boundary conditions, and input the thermodynamic properties of the corresponding material to perform numerical simulation on the thermal mismatch behavior of the discontinuous particle reinforced composite material during the cooling process. This method has low modeling difficulty and few control parameters, and can effectively predict the influence of the reinforcement phase particle shape on the thermal residual stress distribution of the composite material.

Description

Technical Field

[0001] The invention belongs to the field of novel composite material modeling, and in particular relates to a method for predicting thermal residual stress of a discontinuous particle reinforced composite material. Background Art

[0002] In composite material research, reinforcement particle shape is one of the primary factors influencing performance. It significantly impacts the thermal residual stress of the material. Sharp reinforcements can easily induce localized high residual stresses, leading to microplastic accumulation. Rounded reinforcements alleviate this phenomenon. Currently, experimental studies of the effect of particle shape on the thermal residual stress distribution in composite materials are labor-intensive and time-consuming.

[0003] In recent years, finite element simulation has become a relatively mature application in predicting the coupled thermal-mechanical behavior of composite materials. This method has already achieved highly accurate predictions. Uncovering the influence of particle shape on the thermal residual stress distribution in composite materials requires high-throughput computation. This is a massive modeling undertaking, necessitating the development of a new modeling approach to meet the needs of scientific research. The thermal residual stress distribution predicted by this method can guide material design and meet the needs of new material research and development for engineering applications. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies in the prior art and provide a method for predicting thermal residual stress of discontinuous particle reinforced composite materials.

[0005] The specific technical solutions adopted in the present invention are as follows:

[0006] The present invention provides a method for predicting thermal residual stress of a discontinuous particle reinforced composite material, which comprises the following steps:

[0007] S1: establishing a cube model according to the basic side length, cutting off an equilateral triangle at each vertex of the cube model to obtain an initial convex polyhedron reinforcement phase particle model;

[0008] S2: Set the model length L, the volume fraction of the reinforcement phase particles F, and the number of reinforcement phase particles N to establish the basic model of the composite material;

[0009] S3: Calculate the scaling coefficient and scale the volume of the initial convex polyhedron reinforcement phase particle model established in step S1 to obtain N target convex polyhedron reinforcement phase particle models;

[0010] S4: rotating and translating each target convex polyhedron reinforcement phase particle model after volume scaling in step S3 in space and combining it with the composite material base model established in step S2 to obtain a discontinuous particle reinforced composite material model;

[0011] S5: Meshing the discontinuous particle reinforced composite material model obtained in step S4, applying cooling boundary conditions, and inputting the thermodynamic properties of the composite material base model and the convex polyhedron reinforcement phase particle model. Numerical simulation is performed on the thermal mismatch behavior of the discontinuous particle reinforced composite material during the cooling process to obtain the thermal residual stress distribution of the discontinuous particle reinforced composite material.

[0012] As an example, the side length of the equilateral triangle in step S1 is The structural parameter OFFEST refers to the ratio of the distance from the vertex of the cut-off equilateral triangle to the vertex of the cube model to the basic side length EDGE of the cube model; the value range of the structural parameter OFFEST is 0.0≤OFFSET≤1.0; the centroid of the convex polyhedron reinforcement phase model is located at the origin of the Cartesian coordinate system O(0, 0, 0).

[0013] Preferably, the composite material base model in step S2 is a cube, and the value range of F is 0.0<F≤0.2; one of the vertices of the composite material base model is located at the origin O(0, 0, 0) of the Cartesian coordinate system.

[0014] As an example, the scaling factor in step S3 is

[0015]

[0016] Where VP is the volume of the initial convex polyhedron reinforcement phase particle model; VOLUME is the volume of the target convex polyhedron reinforcement phase particle model; F is the volume fraction of the reinforcement phase particles; N is the number of reinforcement phase particles.

[0017] Furthermore, if the structural parameter OFFEST = 0.0, the volume of the initial convex polyhedron reinforcement phase particle model VP = EDGE 3 ; If the structural parameter OFFSET = 1.0, the volume of the initial convex polyhedron reinforcement phase particle model If the structural parameter OFFSET = 0.5, the volume of the initial convex polyhedron reinforcement phase particle model is If the structural parameter OFFSET is in the range of 0.0<OFFSET<0.5, the volume of the initial convex polyhedron reinforcement phase particle model is If the structural parameter OFFSET is in the range of 0.5<OFFSET<1.0, the volume of the initial convex polyhedron reinforcement phase particle model

[0018]

[0019] Preferably, the specific steps of constructing the discontinuous particle reinforced composite material model in step S4 are as follows:

[0020] S41: Establish a particle set Set_P;

[0021] S42: Rotate the target convex polyhedron reinforcing phase particle model by θ around the X-axis, where -45° ≤ θ ≤ 45°, and then rotate it by -90° ≤ θ ≤ 90°; The rotation matrix of the target convex polyhedron reinforcing phase particle model can be expressed as:

[0022]

[0023] Perform a rotation operation on all nodes pold(x, y, z) of each target convex polyhedron reinforcing phase particle model to obtain the rotated convex polyhedron reinforcing phase particle model, and the coordinates of each node pnew(xn, yn, zn):

[0024] pnew(xn, yn, zn) = R rot × pold(x, y, z);

[0025] S43: Calculate the circumradius Rc of the target convex polyhedron reinforcing phase particle model; Move the centroid of each rotated convex polyhedron reinforcing phase particle model respectively, and the coordinates of the moved centroid are denoted as po(xnew, ynew, znew), where Rc ≤ xnew ≤ L - Rc, Rc ≤ ynew ≤ L - Rc, Rc ≤ znew ≤ L - Rc; If the rotated convex polyhedron reinforcing phase particle model is completely located within the composite material base model, then retain the convex polyhedron reinforcing phase particle model in the composite material base model;

[0026] If the rotated convex polyhedron reinforcing phase particle model is not completely located within the composite material base model, then perform the following operations:

[0027] S431: If |xnew - L| < Rc, then translate the convex polyhedron reinforcing phase particle model along the X direction by -L; If |ynew - L| < Rc, then translate the convex polyhedron reinforcing phase particle model along the Y direction by -L; If |znew - L| < Rc, then translate the convex polyhedron reinforcing phase particle model along the Z direction by -L to obtain the translated convex polyhedron reinforcing phase particle model;

[0028] S432: If any node of the composite material base model is within the translated convex polyhedron reinforcing phase particle model, then copy the translated convex polyhedron reinforcing phase particle model 7 times and move the centroid to (0, 0, L), (0, L, 0), (0, L, L), (L, 0, L), (L, L, 0), (L, L, L), (L, 0, 0) respectively, so that each node of the composite material base model passes through a convex polyhedron reinforcing phase particle model, and retain the model part in the composite material base model;

[0029] If any edge of the composite material base model passes through the translated convex polyhedron reinforcement phase particle model, then copy the translated convex polyhedron reinforcement phase particle model three times and move the centroids respectively so that all four edges in that direction pass through a convex polyhedron reinforcement phase particle model, and the model part in the composite material base model is retained;

[0030] If any surface of the composite material base model passes through the translated convex polyhedron reinforcement phase particle model, then copy the translated convex polyhedron reinforcement phase particle model once and move the centroid so that each surface in that direction passes through a convex polyhedron reinforcement phase particle model, and the model part in the composite material base model is retained;

[0031] S44: Calculate the circumscribed sphere radius Rc of the target convex polyhedron reinforcement phase particle model; each time the convex polyhedron reinforcement phase particle model is moved, perform collision detection with the model portion retained in the composite material base model: the collision detection formula is as follows:

[0032] 4Rc 2 >=(x1-x2) 2 +(y1-y2) 2 +(z1-z2) 2

[0033] Each time the centroid of the convex polyhedron reinforcement phase particle model is moved, it is (x1, y1, z1), and the centroid of the convex polyhedron reinforcement phase particle model retained in the composite material basic model is (x2, y2, z2);

[0034] If the above collision detection formula is satisfied, the convex polyhedron reinforcement phase particle model is transferred to the particle set Set_P; if the above collision detection formula is not satisfied, the convex polyhedron reinforcement phase particle model is deleted from the composite material base model;

[0035] S45: Assemble the particle set Set_P and the composite material basic model established in step S2 into an entity to obtain a discontinuous particle reinforced composite material model.

[0036] Furthermore, the circumscribed sphere radius Rc of the target convex polyhedron reinforcement phase particle model is calculated as follows:

[0037] If the structural parameter OFFEST = 0.0, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFEST = 1.0, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFEST = 0.5, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFSET is in the range of 0.0<OFFSET<0.5, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFSET is in the range of 0.5<OFFSET<1.0, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model

[0038] Preferably, the mesh type in the mesh division in step S5 is a 4-node tetrahedron unit, and the total number of mesh units is not less than 700,000.

[0039] Preferably, the thermodynamic properties in step S5 include elastic properties, plastic properties and expansion properties; the elastic properties include Young's modulus and Poisson's ratio, the plastic properties are the plastic deformation stress-strain relationship, and the expansion properties are the thermal expansion coefficient.

[0040] Preferably, the cooling boundary conditions in step S5 are set as follows: a temperature range of 0 to 1600°C, and a cooling rate ΔT of 10 to 200°C.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The present invention provides a method for predicting thermal residual stress of discontinuous particle-reinforced composite materials. This method regulates the shape of convex polyhedral reinforcement phase particles from cube to regular octahedron by adjusting a structural parameter. The method has simple steps, low modeling difficulty, and few control parameters.

[0043] (2) The present invention uses simulation technology to predict the thermal residual stress distribution of a constructed discontinuous particle-reinforced composite model. The method provided by the present invention can effectively predict the effect of the shape control of the convex polyhedron reinforcement phase particles on the thermal residual stress distribution of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the initial convex polyhedron reinforcement phase particle model provided in the embodiment, where (a) to (e) are when the structural parameter OFFEST is 0.0, 0.25, 0.5, 0.75 and 1.0 respectively;

[0045] Figure 2 Schematic diagram of the discontinuous particle reinforced composite material model provided in the embodiment, where (a) to (e) are when the structural parameter OFFEST is 0.0, 0.25, 0.5, 0.75 and 1.0 respectively;

[0046] Figure 31 and 2 are cloud diagrams of thermal residual stress simulation of the discontinuous particle reinforced composite material in the embodiment, where (a) to (e) are when the structural parameter OFFEST is 0.0, 0.25, 0.5, 0.75 and 1.0, respectively. DETAILED DESCRIPTION

[0047] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention may be combined accordingly, provided that there is no conflict between them.

[0048] The present invention provides a method for predicting thermal residual stress of a discontinuous particle reinforced composite material, which comprises the following steps:

[0049] 1. Set up the initial convex polyhedron reinforcement phase particle model.

[0050] A cube model is established based on the basic side length EDGE, and an equilateral triangle is cut off at each vertex of the cube model to obtain an initial convex polyhedron reinforcement phase particle model. The centroid of the initial convex polyhedron reinforcement phase model is located at the origin O(0,0,0) of the Cartesian coordinate system.

[0051] The side length of the equilateral triangle, L', is √2 × EDGE × OFFEST. The structural parameter OFFEST is the ratio of the distance from the vertex of the cut-off equilateral triangle to the vertex of the cube model to the length of the cube model's base side, EDGE. The value range of the structural parameter OFFEST is 0.0 ≤ OFFSET ≤ 1.0.

[0052] Specific as Figure 1 As shown in Figure 2, when the structural parameter OFFEST is set to 0.0, 0.25, 0.5, 0.75, and 1.0, the structure of the initial convex polyhedron reinforcement phase particle model is as follows: Figure 1 (a)~ Figure 1 (e) shown.

[0053] 2. Establish a basic model of composite materials.

[0054] The composite material basic model is a cube with a model length of L. The volume fraction of the reinforcement phase particles F and the number of reinforcement phase particles N are set to obtain the composite material basic model. The value range of F is 0.0<F≤0.2.

[0055] One of the vertices of the composite material basic model is located at the origin O(0, 0, 0) of the Cartesian coordinate system, and the other vertices are V1(L, 0, 0), V2(L, L, 0), V3(0, L, 0), V4(0, 0, L), V5(L, 0, L), V6(L, L, L), and V7(0, L, L).

[0056] 3. Scale the initial convex polyhedron reinforcement phase particle model.

[0057] (1) Calculate the scaling factor

[0058]

[0059] Where VP is the volume of the initial convex polyhedron reinforcement phase particle model; VOLUME is the volume of the target convex polyhedron reinforcement phase particle model; F is the volume fraction of the reinforcement phase particles; N is the number of reinforcement phase particles.

[0060] It should be noted that if the structural parameter OFFEST = 0.0, the volume of the initial convex polyhedron reinforcement phase particle model VP = EDGE 3 ; If the structural parameter OFFSET = 1.0, the volume of the initial convex polyhedron reinforcement phase particle model If the structural parameter OFFSET = 0.5, the volume of the initial convex polyhedron reinforcement phase particle model is If the structural parameter OFFSET is in the range of 0.0<OFFSET<0.5, the volume of the initial convex polyhedron reinforcement phase particle model is If the structural parameter OFFSET is in the range of 0.5<OFFSET<1.0, the volume of the initial convex polyhedron reinforcement phase particle model

[0061]

[0062] (2) The volume of the initial convex polyhedron reinforcement phase particle model established in step 1 is scaled to obtain N target convex polyhedron reinforcement phase particle models.

[0063] 4. Construct a model of discontinuous particle reinforced composite materials.

[0064] After the volume scaling of each target convex polyhedron reinforcement phase particle model in step 3 is spatially rotated and translated, it is combined with the composite material basic model established in step 2 to obtain a discontinuous particle reinforced composite material model, as follows:

[0065] (1) Create a particle set Set_P; at this time, the particle set is an empty set.

[0066] (2) Rotate the target convex polyhedron reinforcement phase particle model around the X axis by θ, -45°≤θ≤45°, and then rotate it around the Y axis -90°≤θ≤90°; the rotation matrix of the target convex polyhedron reinforcement phase particle model can be expressed as:

[0067]

[0068] Perform a rotation operation on all nodes pold(x, y, z) of each target convex polyhedron reinforced phase particle model to obtain the rotated convex polyhedron reinforced phase particle model, and the coordinates of each node pnew(xn, yn, zn):

[0069] pnew(xn, yn, zn) = R rot × pold(x, y, z);

[0070] (3) Move the centroid of each rotated convex polyhedron reinforced phase particle model respectively, and the coordinates of the moved centroid are denoted as po(xnew, ynew, znew), where 0 ≤ xnew ≤ L, 0 ≤ ynew ≤ L, 0 ≤ znew ≤ L;

[0071] If the rotated convex polyhedron reinforced phase particle model is completely located within the composite material base model, then retain this convex polyhedron reinforced phase particle model in the composite material base model;

[0072] If the rotated convex polyhedron reinforced phase particle model is not completely located within the composite material base model, then perform the following operations:

[0073] 1) If |xnew - L| < Rc, then translate this convex polyhedron reinforced phase particle model along the X direction by -L; if |ynew - L| < Rc, then translate this convex polyhedron reinforced phase particle model along the Y direction by -L; if |znew - L| < Rc, then translate this convex polyhedron reinforced phase particle model along the Z direction by -L to obtain the translated convex polyhedron reinforced phase particle model; Rc is the radius of the circumscribed sphere of the target convex polyhedron reinforced phase particle model;

[0074] 2) If any node of the composite material base model is within the translated convex polyhedron reinforced phase particle model, then copy this translated convex polyhedron reinforced phase particle model 7 times and move the centroid to (0, 0, L), (0, L, 0), (0, L, L), (L, 0, L), (L, L, 0), (L, L, L), (L, 0, 0) respectively, so that each node of the composite material base model passes through a convex polyhedron reinforced phase particle model, and retain the model part in the composite material base model;

[0075] If any edge of the composite material base model passes through the translated convex polyhedron reinforced phase particle model, then copy this translated convex polyhedron reinforced phase particle model 3 times and move the centroid respectively, so that each of the 4 edges in this direction passes through a convex polyhedron reinforced phase particle model, and retain the model part in the composite material base model;

[0076] Specifically: if the edge X=0, Y=0 passes through the translated convex polyhedron reinforcement phase particle model, it is copied 3 times and the centroid is moved to (L, 0, 0), (0, L, 0), and (L, L, 0) respectively; if the edge Y=0, Z=0 passes through the translated convex polyhedron reinforcement phase particle model, it is copied 3 times and the centroid is moved to (0, L, 0), (0, 0, L), and (0, L, L) respectively; if the edge X=0, Z=0 passes through the translated convex polyhedron reinforcement phase particle model, it is copied 3 times and the centroid is moved to (L, 0, 0), (0, 0, L), and (L, 0, L) respectively; so that the four edges in this direction all pass through a convex polyhedron reinforcement phase particle model.

[0077] If any surface of the composite material base model passes through the translated convex polyhedron reinforcement phase particle model, then copy the translated convex polyhedron reinforcement phase particle model once and move the centroid so that each surface in that direction passes through a convex polyhedron reinforcement phase particle model, and the model part in the composite material base model is retained;

[0078] Specifically: if the edge X=0 passes through the translated convex polyhedron reinforced phase particle model, then copy it once and move the centroid to (L, 0, 0); if the edge Y=0 passes through the translated convex polyhedron reinforced phase particle model, then copy it once and move the centroid to (0, L, 0); if the edge Z=0 passes through the translated convex polyhedron reinforced phase particle model, then copy it once and move the centroid to (0, 0, L); so that the surface in this direction passes through a convex polyhedron reinforced phase particle model.

[0079] (4) Each time the convex polyhedron reinforcement phase particle model is moved, a collision detection is performed with the model part retained in the composite material base model. The collision detection formula is as follows:

[0080] 4Rc 2 >=(x1-x2) 2 +(y1-y2) 2 +(z1-z2) 2

[0081] Each time the centroid of the convex polyhedron reinforcement phase particle model is moved, it is (x1, y1, z1), and the centroid of the convex polyhedron reinforcement phase particle model retained in the composite material basic model is (x2, y2, z2).

[0082] The calculation method of the circumscribed sphere radius Rc of the target convex polyhedron reinforcement phase particle model is as follows:

[0083] If the structural parameter OFFEST = 0.0, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFEST = 1.0, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFEST = 0.5, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFSET is in the range of 0.0<OFFSET<0.5, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFSET is in the range of 0.5<OFFSET<1.0, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model

[0084] If the above collision detection formula is satisfied, the convex polyhedron reinforcement phase particle model is transferred to the particle set Set_P; if the above collision detection formula is not satisfied, the convex polyhedron reinforcement phase particle model is deleted from the composite material base model to ensure that the convex polyhedron reinforcement phase particle models in the composite material base model do not overlap.

[0085] (5) Assemble the particle set Set_P and the composite material basic model established in step S2 into an entity to obtain a discontinuous particle reinforced composite material model.

[0086] 5. Grid division and cooling boundary condition setting.

[0087] The resulting discontinuous particle-reinforced composite model was meshed using a 4-node tetrahedral mesh with a total of no fewer than 700,000 mesh elements. A cooling boundary condition was applied, with a temperature range of 0 to 1600°C and a cooling rate ΔT of 10 to 200°C. The thermodynamic properties (including elastic, plastic, and expansion properties) of the composite base model and the convex polyhedral reinforcement phase particle model were input to numerically simulate the thermal mismatch behavior of the discontinuous particle-reinforced composite during cooling, and the thermal residual stress distribution of the discontinuous particle-reinforced composite was determined.

[0088] It should be noted that elastic properties include Young's modulus and Poisson's ratio, expansion properties include thermal expansion coefficient, and plastic properties include plastic deformation stress-strain relationship. The calculation formula for plastic deformation stress-strain relationship is as follows:

[0089] σ=(A+Bε n )

[0090] Where: σ is the matrix flow stress, ε is the plastic strain, and A, B, and n are material-related parameters.

[0091] Example 1

[0092] 1. Set up the initial convex polyhedron reinforcement phase particle model.

[0093] The basic edge length EDGE is set to 1000, and the structural parameter OFFSET is set to 0.0, 0.25, 0.5, 0.75, and 1.0 respectively. The initial convex polyhedron reinforcement phase particle model is as follows: Figure 1 shown.

[0094] 2. Establish a basic model of composite materials.

[0095] The basic model of the composite material is a cube, the model length is L=100, the volume fraction of the reinforcement phase particles is set to F=0.1, and the number of reinforcement phase particles N=50.

[0096] 3. Calculate the scaling coefficient and scale the initial convex polyhedron reinforcement phase particle model to obtain the target convex polyhedron reinforcement phase particle model.

[0097] 4. Construct a model of discontinuous particle reinforced composite materials, as follows Figure 2 shown.

[0098] 5. The discontinuous particle reinforced composite material model is meshed. The mesh type is 4-node tetrahedron element, and the total number of mesh elements is 828,000.

[0099] 6. Input the thermodynamic properties of the composite material base model and the convex polyhedron reinforcement phase particle model.

[0100] The composite material base model is aluminum alloy with a Young's modulus of 70 GPa, a Poisson's ratio of 0.33, and a thermal expansion coefficient of 23.2×10 -6 / K; the convex polyhedron reinforcement phase particle model material is silicon carbide, with a Young's modulus of 427 GPa, a Poisson's ratio of 0.17, and a thermal expansion coefficient of 4.0×10 -6 / K.

[0101] The relationship between the plastic deformation stress (σ) and strain (ε) of aluminum alloy is as follows:

[0102] σ=A+Bε n

[0103] Among them, A is 240.09, B is 200.07, and n is 0.2.

[0104] 7. Apply cooling boundary conditions.

[0105] Enter the temperature field parameters, the high temperature is 500℃, the low temperature is 20℃, and the cooling rate is 120℃.

[0106] 8. Calculate the thermal residual stress distribution of the above-mentioned discontinuous particle reinforced composite material model material based on finite element software.

[0107] In this example, finite element models of five different silicon carbide particle-reinforced aluminum composites were established. The particle shapes are diverse, and as the structural parameter OFFSET increases, the particle shapes transition from cube to tetradecahedron to octahedron. Figure 3 The cross-sectional view of the residual stress distribution of the aluminum matrix at x = 50 shows that as offset increases, the stress gradient in the matrix near the interface increases, while the stress level in the low-stress region farther from the interface increases and the area decreases (blue area). This significant change in the thermal residual stress distribution occurs. This demonstrates that the model established using the method provided by this invention can effectively predict the effect of particle shape manipulation on the thermal residual stress distribution of composite materials.

[0108] The embodiment described above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Persons skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent substitution or equivalent transformation falls within the scope of protection of the present invention.

Claims

1. A method for predicting thermal residual stress of a discontinuous particle reinforced composite material, characterized in that: The specific steps are as follows: S1: Establish a cube model based on the base side length, and cut off an equilateral triangle at each vertex of the cube model to obtain an initial convex polyhedron reinforced phase particle model; S2: Set the model length L, the volume fraction F of the reinforced phase particles, and the number N of the reinforced phase particles to establish a basic composite material model; S3: Calculate the scaling coefficient S, and perform volume scaling on the initial convex polyhedron reinforced phase particle model established in step S1 to obtain N target convex polyhedron reinforced phase particle models; S4: Rotate and translate each target convex polyhedron reinforced phase particle model obtained by volume scaling in step S3 in space and combine it with the basic composite material model established in step S2 to obtain a discontinuous particle reinforced composite material model; S5: Perform mesh division on the discontinuous particle reinforced composite material model obtained in step S4, apply a cooling boundary condition, and input the thermodynamic properties of the basic composite material model and the convex polyhedron reinforced phase particle model to perform numerical simulation on the thermal mismatch behavior during the cooling process of the discontinuous particle reinforced composite material, and obtain the thermal residual stress distribution of the discontinuous particle reinforced composite material; The specific steps for constructing the discontinuous particle reinforced composite material model in step S4 are as follows: S41: Establish a particle set Set_P; S42: Rotate the target convex polyhedron reinforcement phase particle model around the X axis by θ, -45°≤θ≤45°, and then rotate it around the Y axis The rotation matrix of the target convex polyhedron reinforcement phase particle model can be expressed as: Perform a rotation operation on all nodes pold(x, y, z) of each target convex polyhedron reinforced phase particle model to obtain a rotated convex polyhedron reinforced phase particle model, and the coordinates of each node pnew(xn, yn, zn): pnew(xn,in,zn)=R rot ×pold(x,y,z); S43: Calculate the circumradius Rc of the target convex polyhedron reinforced phase particle model; move the centroid of each rotated convex polyhedron reinforced phase particle model respectively, and the coordinates of the moved centroid are denoted as po(xnew, ynew, znew), Rc ≤ xnew ≤ L - Rc, Rc ≤ ynew ≤ L - Rc, Rc ≤ znew ≤ L - Rc; if the rotated convex polyhedron reinforced phase particle model is completely located in the basic composite material model, then retain the convex polyhedron reinforced phase particle model in the basic composite material model; If the rotated convex polyhedron reinforced phase particle model is not completely located in the basic composite material model, then perform the following operations: S431: If |xnew - L| < Rc, then translate the convex polyhedron reinforced phase particle model along the X direction by -L; if |ynew - L| < Rc, then translate the convex polyhedron reinforced phase particle model along the Y direction by -L; if |znew - L| < Rc, then translate the convex polyhedron reinforced phase particle model along the Z direction by -L to obtain a translated convex polyhedron reinforced phase particle model; S432: If any node of the composite material base model is within the translated convex polyhedron reinforcement phase particle model, copy the translated convex polyhedron reinforcement phase particle model seven times, and move the centroids to (0, 0, L), (0, L, 0), (0, L, L), (L, 0, L), (L, L, 0), (L, L, L), (L, 0, 0), so that each node of the composite material base model passes through a convex polyhedron reinforcement phase particle model, and the model portion is retained in the composite material base model; If any edge of the composite material base model passes through the translated convex polyhedron reinforcement phase particle model, then copy the translated convex polyhedron reinforcement phase particle model three times and move the centroids respectively so that all four edges in that direction pass through a convex polyhedron reinforcement phase particle model, and the model part in the composite material base model is retained; If any surface of the composite material base model passes through the translated convex polyhedron reinforcement phase particle model, then copy the translated convex polyhedron reinforcement phase particle model once and move the centroid so that each surface in that direction passes through a convex polyhedron reinforcement phase particle model, and the model part in the composite material base model is retained; S44: Each time the convex polyhedron reinforcement phase particle model is moved, a collision detection is performed with the model part retained in the composite material base model: the collision detection formula is as follows: <h2 style=";text-align:left;direction:ltr">4Rc<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> >=(x1-x2)<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +(y1-y2)<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +(z1-z2)<h2 style=";text-align:left;direction:ltr"> 2 Each time the centroid of the convex polyhedron reinforcement phase particle model is moved, it is (x1, y1, z1), and the centroid of the convex polyhedron reinforcement phase particle model retained in the composite material basic model is (x2, y2, z2); If the above collision detection formula is satisfied, the convex polyhedron reinforcement phase particle model is transferred to the particle set Set_P; if the above collision detection formula is not satisfied, the convex polyhedron reinforcement phase particle model is deleted from the composite material base model; S45: Assemble the particle set Set_P and the composite material basic model established in step S2 into an entity to obtain a discontinuous particle reinforced composite material model.

2. The method for predicting thermal residual stress of a discontinuous particle reinforced composite material according to claim 1, characterized in that: The side length of the equilateral triangle in step S1 The structural parameter OFFEST refers to the ratio of the distance from the vertex of the cut-off equilateral triangle to the vertex of the cube model to the basic side length EDGE of the cube model; the value range of the structural parameter OFFEST is 0.0≤OFFSET≤1.0; the centroid of the convex polyhedron reinforcement phase model is located at the origin of the Cartesian coordinate system O(0, 0, 0).

3. The method for predicting thermal residual stress of a discontinuous particle reinforced composite material according to claim 1, characterized in that: In step S2, the composite material base model is a cube, and the value range of F is 0.0<F≤0.2; one of the vertices of the composite material base model is located at the origin O(0, 0, 0) of the Cartesian coordinate system.

4. The method for predicting thermal residual stress of a discontinuous particle reinforced composite material according to claim 1, characterized in that: The scaling factor in step S3 Where VP is the volume of the initial convex polyhedron reinforcement phase particle model; VOLUME is the volume of the target convex polyhedron reinforcement phase particle model; F is the volume fraction of the reinforcement phase particles; N is the number of reinforcement phase particles.

5. The method for predicting thermal residual stress of a discontinuous particle reinforced composite material according to claim 4, characterized in that: If the structural parameter OFFEST = 0.0, the volume of the initial convex polyhedron reinforcement phase particle model VP = EDGE 3 ; If the structural parameter OFFSET = 1.0, the volume of the initial convex polyhedron reinforcement phase particle model If the structural parameter OFFSET = 0.5, the volume of the initial convex polyhedron reinforcement phase particle model is If the structural parameter OFFSET is in the range of 0.0<OFFSET<0.5, the volume of the initial convex polyhedron reinforcement phase particle model is If the structural parameter OFFSET is in the range of 0.5<OFFSET<1.0, the volume of the initial convex polyhedron reinforcement phase particle model 6. The method for predicting thermal residual stress of a discontinuous particle reinforced composite material according to claim 1, characterized in that: The calculation method of the circumscribed sphere radius Rc of the target convex polyhedron reinforcement phase particle model is as follows: If the structural parameter OFFEST = 0.0, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFEST = 1.0, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFEST = 0.5, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFSET is in the range of 0.0<OFFSET<0.5, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model If the structural parameter OFFSET is in the range of 0.5<OFFSET<1.0, the radius of the circumscribed sphere of the convex polyhedron reinforcement phase particle model 7. The method for predicting thermal residual stress of a discontinuous particle reinforced composite material according to claim 1, characterized in that: The mesh type in the mesh division in step S5 is a 4-node tetrahedron unit, and the total number of mesh units is not less than 700,000.

8. The method for predicting thermal residual stress of a discontinuous particle reinforced composite material according to claim 1, characterized in that: The thermodynamic properties in step S5 include elastic properties, plastic properties and expansion properties; the elastic properties include Young's modulus and Poisson's ratio, the plastic properties are the stress-strain relationship of plastic deformation, and the expansion properties are the thermal expansion coefficient.

9. The method for predicting thermal residual stress of a discontinuous particle reinforced composite material according to claim 1, characterized in that: The cooling boundary conditions in step S5 are set as follows: temperature range 0-1600°C, cooling rate ΔT 10-200°C.

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