Prediction method for thermal residual stress of discontinuous particle reinforced composite material

Abstract

The invention discloses a prediction method for thermal residual stress of a discontinuous particle reinforced composite material, and belongs to the field of novel composite material modeling. The method specifically comprises the following steps: 1) constructing an initial convex polyhedron reinforced phase particle model; 2) establishing a composite material basic model; 3) performing volume scaling on the initial convex polyhedron reinforced phase particle model to obtain N target convex polyhedron reinforced phase particle models; 4) performing spatial rotation and translation on each target convex polyhedron reinforced phase particle model, and then combining the target convex polyhedron reinforced phase particle model with the composite material basic model to obtain a discontinuous particle reinforced composite material model; and 5) carrying out grid division, applying cooling boundary conditions, inputting thermodynamic attributes of corresponding materials, and carrying out numerical simulation on thermal mismatch behaviors in the cooling process of the discontinuous particle reinforced composite material. The method has the advantages of low modeling difficulty and few control parameters, and can effectively predict the influence of the reinforced 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 the study of composite materials, the shape of reinforcement particles is one of the main factors affecting performance. The shape of reinforcement particles will significantly affect the thermal residual stress of the material. If the reinforcement is sharp, it is easy to cause local high residual stress, resulting in micro-area plastic accumulation. If the reinforcement is round, this phenomenon will be alleviated. At present, experimental methods are used to study the effect of particle shape on the distribution of thermal residual stress in composite materials, which consumes a lot of manpower and time costs.

[0003] In recent years, finite element simulation has been relatively maturely applied to the prediction of thermal-mechanical coupling behavior of composite materials. This method has been able to obtain high-precision prediction results. High-throughput calculations are required to reveal the influence of particle shape on the thermal residual stress distribution of composite materials. This is a huge modeling project, so it is urgent to develop a new modeling method 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 in 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 a discontinuous particle reinforced composite material.

[0005] The specific technical solutions adopted by 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, and the specific steps are as follows:

[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 F of the reinforcement phase particles and the number N of the reinforcement phase particles 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 polyhedral reinforcement phase particle model after volume scaling in step S3 in space and combining it with the composite material basic 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, numerically simulating the thermal mismatch behavior of the discontinuous particle reinforced composite material during the cooling process, and obtaining the thermal residual stress distribution of the discontinuous particle reinforced composite material.

[0012] Preferably, 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 enhanced phase model is located at the origin O(0, 0, 0) of the Cartesian coordinate system.

[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] Preferably, the scaling factor in step S3

[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 VP of the initial convex polyhedral reinforcement phase particle model is 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 If the structural parameter OFFSET is in the range of 0.0<OFFSET<0.5, the volume of the initial convex polyhedral reinforcement phase particle model If the structural parameter OFFSET is in the range of 0.5<OFFSET<1.0, the volume of the initial convex polyhedral 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 basic model, then retain the convex polyhedron reinforcing phase particle model in the composite material basic model;

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

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

[0028] S432: If any node of the composite material basic 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 basic model passes through a convex polyhedron reinforcing phase particle model, and retain the model part in the composite material basic model;

[0029] If any edge of the composite material base model passes through the translated convex polyhedron reinforcement phase particle model, the translated convex polyhedron reinforcement phase particle model is copied three times, and the centroids are moved respectively so that the four edges in the 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 the surface in this direction passes through a convex polyhedron reinforcement phase particle model, and retain the model part in the composite material base model;

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

[0032] 4R 2 >=(x 1 -x 2 ) 2 +(y 1 -y 2 ) 2 +(z 1 -z 2 ) 2

[0033] Each time the centroid of the convex polyhedron reinforcement phase particle model is moved, 1 ,y 1 , z 1 ), the centroid of the convex polyhedron reinforcement phase particle model retained in the composite material basic model is (x 2 ,y 2 , z 2 );

[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 basic model;

[0035] S45: Assemble the particle set Set_P and the composite material basic model established in step S2 into one 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 outer sphere of the convex polyhedral reinforcement phase particle model If the structural parameter OFFEST = 1.0, the radius of the outer sphere of the convex polyhedral reinforcement phase particle model If the structural parameter OFFEST = 0.5, the radius of the outer sphere of the convex polyhedral 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 polyhedral 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 polyhedral reinforcement phase particle model

[0038] Preferably, the mesh type in the mesh division in step S5 is a 4-node tetrahedral 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: temperature range 0-1600°C, cooling rate ΔT 10-200°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 a discontinuous particle reinforced composite material. The method adjusts a structural parameter to control the shape of the convex polyhedral reinforcement phase particles from a cube to a regular octahedron. The method has simple steps, low modeling difficulty and few control parameters.

[0043] (2) The present invention predicts the thermal residual stress distribution of the constructed discontinuous particle reinforced composite model through simulation technology. The method provided by the present invention can effectively predict the influence of the shape control of the convex polyhedral 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, wherein (a) to (e) are when the structural parameter OFFEST is 0.0, 0.25, 0.5, 0.75 and 1.0 respectively;

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

[0046] Figure 3 1 is a cloud diagram 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 is further described and illustrated below in conjunction with the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0048] The present invention provides a method for predicting thermal residual stress of a discontinuous particle reinforced composite material, and the specific steps are as follows:

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

[0050] A cube model is established according to 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'=√2×EDGE×OFFEST; 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.

[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 respectively, the structure of the initial convex polyhedron reinforcement phase particle model is as follows: Figure 1 (a)~ Figure 1 (e) as shown.

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

[0054] The basic model of the composite material is a cube, the model length is L, and the volume fraction F of the reinforcement phase particles and the number N of the reinforcement phase particles are set to obtain the basic model of the composite material. 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 polyhedral 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 VP of the initial convex polyhedral reinforcement phase particle model is 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 If the structural parameter OFFSET is in the range of 0.0<OFFSET<0.5, the volume of the initial convex polyhedral reinforcement phase particle model If the structural parameter OFFSET is in the range of 0.5<OFFSET<1.0, the volume of the initial convex polyhedral reinforcement phase particle model

[0061]

[0062] (2) Scaling the volume of the initial convex polyhedron reinforcement phase particle model established in step 1 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 polyhedral 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 reinforcing 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 reinforcing phase particle model to obtain the rotated convex polyhedron reinforcing 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 reinforcing phase particle model respectively, and the coordinates of the moved centroid are denoted as po(xnew, ynew, znew), 0 ≤ xnew ≤ L, 0 ≤ ynew ≤ L, 0 ≤ znew ≤ L;

[0071] 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;

[0072] If the rotated convex polyhedron reinforcing 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 the convex polyhedron reinforcing phase particle model by -L along the X direction; if |ynew - L| < Rc, then translate the convex polyhedron reinforcing phase particle model by -L along the Y direction; if |znew - L| < Rc, then translate the convex polyhedron reinforcing phase particle model by -L along the Z direction to obtain the translated convex polyhedron reinforcing phase particle model; Rc is the radius of the circumscribed sphere of the target convex polyhedron reinforcing phase particle model;

[0074] 2) 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;

[0075] If any edge of the composite material base model passes through the translated convex polyhedron reinforcement phase particle model, the translated convex polyhedron reinforcement phase particle model is copied three times, and the centroids are moved respectively so that the four edges in the direction pass through a convex polyhedron reinforcement phase particle model, and the model part in the composite material base model is retained;

[0076] Specifically: if the edge X=0, Y=0 passes through the translated convex polyhedron reinforcement phase particle model, then copy it 3 times and move the centroid to (L, 0, 0), (0, L, 0), (L, L, 0) respectively; if the edge Y=0, Z=0 passes through the translated convex polyhedron reinforcement phase particle model, then copy it 3 times and move the centroid to (0, L, 0), (0, 0, L), (0, L, L) respectively; if the edge X=0, Z=0 passes through the translated convex polyhedron reinforcement phase particle model, then copy it 3 times and move the centroid to (L, 0, 0), (0, 0, L), (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 the surface in this direction passes through a convex polyhedron reinforcement phase particle model, and retain the model part in the composite material base model;

[0078] Specifically: if 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 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 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 each 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] 4R 2 >=(x 1 -x 2 ) 2 +(y 1 -y 2 ) 2 +(z 1 -z 2 ) 2

[0081] Each time the centroid of the convex polyhedron reinforcement phase particle model is moved, 1,y 1 , z 1 ), the centroid of the convex polyhedron reinforcement phase particle model retained in the composite material basic model is (x 2 ,y 2 , z 2 ).

[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 outer sphere of the convex polyhedral reinforcement phase particle model If the structural parameter OFFEST = 1.0, the radius of the outer sphere of the convex polyhedral reinforcement phase particle model If the structural parameter OFFEST = 0.5, the radius of the outer sphere of the convex polyhedral 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 polyhedral 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 polyhedral 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 basic model to ensure that the convex polyhedron reinforcement phase particle models in the composite material basic 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 setting of cooling boundary conditions.

[0087] The obtained discontinuous particle reinforced composite material model is meshed, and the mesh type in the meshing is 4-node tetrahedral unit, and the total number of mesh units is not less than 700,000. A cooling boundary condition is applied, the temperature range is 0-1600℃, and the cooling rate ΔT is 10-200℃. The thermodynamic properties (including elastic properties, plastic properties and expansion properties) of the composite material basic model and the convex polyhedral reinforcement phase particle model are input, and the thermal mismatch behavior of the discontinuous particle reinforced composite material during the cooling process is numerically simulated to obtain the thermal residual stress distribution of the discontinuous particle reinforced composite material.

[0088] It should be noted that the elastic properties include Young's modulus and Poisson's ratio, the expansion property is the thermal expansion coefficient, and the plastic property is the plastic deformation stress-strain relationship. The calculation formula for the 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 polyhedral 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 factor 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 non-continuous particle reinforced composite material model is meshed. The mesh type is 4-node tetrahedral unit and the total number of mesh units is 828,000.

[0099] 6. Input the thermodynamic properties of the composite material base model and the convex polyhedral 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 427GPa, 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] Input 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 model material based on finite element software.

[0107] In this embodiment, five finite element models of silicon carbide particle reinforced aluminum composite materials are established. The particle shapes are rich, and as the structural parameter OFFSET increases, the particle shapes achieve a transition from cube to tetradecahedron to octahedron. Figure 3 The cross-sectional diagram of the residual stress distribution of the matrix aluminum at X=50 shows that as OFFSET increases, the stress gradient of the matrix near the interface increases, and the stress level of the low stress area far from the interface increases and the area decreases (blue area). The thermal residual stress distribution has changed significantly. This shows that the model established by the method provided by the present invention can effectively predict the effect of particle shape control on the thermal residual stress distribution of the composite material.

[0108] The above-described embodiment is only a preferred solution of the present invention, but it is not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope 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 according to 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 factor, 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 after 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, and perform numerical simulation on the thermal mismatch behavior during the cooling process of the discontinuous particle reinforced composite material to obtain the thermal residual stress distribution of the discontinuous particle reinforced composite material.

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 enhanced phase model is located at the origin O(0, 0, 0) of the Cartesian coordinate system.

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 basic composite material model is a cube, and the value range of F is 0.0 < F ≤ 0.2; one of the vertices of the basic composite material 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 reinforced phase particle model; VOLUME is the volume of the target convex polyhedron reinforced phase particle model; F is the volume fraction of the reinforced phase particles; N is the number of the reinforced 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 polyhedral 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 If the structural parameter OFFSET is in the range of 0.0<OFFSET<0.5, the volume of the initial convex polyhedral reinforcement phase particle model If the structural parameter OFFSET is in the range of 0.5<OFFSET<1.0, the volume of the initial convex polyhedral 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 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 polyhedral 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: 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 after movement, 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 after movement, 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 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 reinforcement phase particle model, and the model part in the composite material base model is retained; If any edge of the composite material base model passes through the translated convex polyhedron reinforcement phase particle model, the translated convex polyhedron reinforcement phase particle model is copied three times, and the centroids are moved respectively so that the four edges in the 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 the surface in this direction passes through a convex polyhedron reinforcement phase particle model, and retain the model part in the composite material base model; 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 basic model; S45: Assemble the particle set Set_P and the composite material basic model established in step S2 into one entity to obtain a discontinuous particle reinforced composite material model.

7. The method for predicting thermal residual stress of a discontinuous particle reinforced composite material according to claim 6, 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 outer sphere of the convex polyhedral reinforcement phase particle model If the structural parameter OFFEST = 1.0, the radius of the outer sphere of the convex polyhedral reinforcement phase particle model If the structural parameter OFFEST = 0.5, the radius of the outer sphere of the convex polyhedral 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 polyhedral 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 polyhedral reinforcement phase particle model 8. 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 tetrahedral unit, and the total number of mesh units is not less than 700,000.

9. 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.

10. 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: the temperature range is 0 to 1600°C, and the cooling rate ΔT is 10 to 200°C.

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