A method for predicting thermal residual stress in quasi-continuous network composite materials
By establishing a convex polyhedron reinforcement phase model and mesh structure parameters in 3D modeling software and combining it with finite element simulation, the problem of predicting the thermal residual stress distribution of quasi-continuous composite materials was solved, and the prediction of thermal stress distribution of complex structures was realized.
Patent Information
- Application Number
- CN202411349615.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2044-09-26
AI Technical Summary
Existing technologies make it difficult to effectively predict the thermal residual stress distribution of quasi-continuous network composite materials, model establishment is difficult, and simulation prediction work is difficult to carry out.
By establishing a geometric model of a convex polyhedron reinforcement phase in 3D modeling software, setting the mesh structure parameters, calculating the position and quantity of the reinforcement phase, performing mesh division, and applying cooling boundary conditions, numerical simulation is performed using finite element software to obtain the thermal residual stress distribution.
The geometric model of quasi-continuous composite materials is established, which can predict the distribution of thermal residual stress, support different types of reinforcement phase shapes, simplify the modeling process and improve the accuracy of prediction.
Smart Images
Figure CN119324017B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of novel composite material configuration design and model establishment, and particularly relates to a method for predicting thermal residual stress of a quasi-continuous network composite material. Background Art
[0002] Quasi-continuous network composites are a new type of composite material in which reinforcements are distributed in a network-like structure around matrix particles. In recent years, quasi-continuous network composites have attracted the attention of numerous researchers and engineers. In composite material research, the distribution characteristics of the reinforcement phase are one of the main factors affecting performance. However, the quasi-continuous network distribution of the reinforcement phase can significantly affect the thermal residual stress distribution of the composite material after cooling. Because it promotes the local volume fraction of the reinforcement phase, the material's residual stress gradient is large and stress concentration occurs. The complex microstructure resulting from the quasi-continuous network distribution makes it difficult to study the distribution characteristics—the distribution patterns of thermal residual stress—through trial and error.
[0003] Currently, finite element simulation technology has been maturely applied in the study of the mechanical behavior of materials under thermal-mechanical coupling conditions in composite materials. This technology can stably and accurately predict the elastic-plastic and thermal behavior of materials, and has successfully completed thermal residual stress analysis in some simple structural composite materials. However, when faced with complex quasi-continuous network composite materials, simulation and prediction work remains difficult due to backward modeling technology. Therefore, the current scientific research and engineering fields urgently need a new modeling technology breakthrough and its application to the prediction of thermal residual stress in quasi-continuous network composite materials to meet the material research and development needs of scientific research and engineering fields. Summary of the Invention
[0004] The purpose of the present invention is to address the problems in the prior art such as difficulty in establishing a quasi-continuous composite material model and difficulty in predicting the influence of thermal residual stress, and to provide a method for predicting the thermal residual stress of a quasi-continuous network composite material.
[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 quasi-continuous network composite material, which comprises the following steps:
[0007] S1: In the 3D modeling software, a geometric model of the convex polyhedron reinforcement phase is established according to the geometric parameters of the convex polyhedron reinforcement phase;
[0008] S2: Set mesh structure parameters and establish mesh structure geometric model;
[0009] S3: setting the volume fraction of the convex polyhedron reinforcement phase, and calculating the number of convex polyhedron reinforcement phases accommodated in the network plane based on the network structure geometric model obtained in step S2;
[0010] S4: Based on the number of convex polyhedral reinforcement phases accommodated in the network plane calculated in step S3, the position of the convex polyhedral reinforcement phase is calculated;
[0011] S5: Based on the position of the convex polyhedron reinforcement phase obtained in step S4, the convex polyhedron reinforcement phase geometric model established in step S1 is inserted into the plane of all the network structure geometric models to obtain a quasi-continuous network composite material geometric model;
[0012] S6: Meshing the geometric model of the quasi-continuous network composite material obtained in step S5 and applying cooling boundary conditions; inputting material properties, performing numerical simulation on the thermal mismatch behavior of the quasi-continuous network composite material during the cooling process, and obtaining the thermal residual stress distribution of the quasi-continuous network composite material.
[0013] Preferably, the geometric parameters of the convex polyhedron reinforcement phase in step S1 include the volume of the convex polyhedron and the radius of the circumscribed circle of the cross section of the XOY plane; the center point of the convex polyhedron reinforcement phase is the origin of the Cartesian coordinate system O(0, 0, 0), and the convex polyhedron reinforcement is mirror-symmetrical with respect to the XOY plane and has an even number of rotational symmetry about the Z axis.
[0014] Preferably, the number of network plane edges of the mesh structure geometric model in step S2 is not less than 4, the internal angle of the network plane is not less than 90°, and the average aspect ratio of the network plane is not higher than 2:1.
[0015] Preferably, the mesh structure parameters in step S2 include model size, number of mesh cells and angular distribution of average angles of network planes.
[0016] As an example, the network plane in step S3 accommodates the number N of convex polyhedron reinforcement phases. i The calculation method is as follows:
[0017] S31: Calculate the total number N of convex polyhedral reinforcement phases:
[0018]
[0019] Where: VF is the volume fraction of the convex polyhedron reinforcement phase; VP is the volume of the convex polyhedron reinforcement phase; L is the model size;
[0020] S32: Calculate the area ratio sr of the i-th network plane in the mesh structure geometric model i :
[0021]
[0022] Where: S i is the area of the ith network plane, S net is the total area of the mesh structure geometric model;
[0023] S33: Calculate the number N of convex polyhedron enhancement phases accommodated by the i-th network plane i =N×sr i .
[0024] Preferably, the specific method for calculating the position of the convex polyhedron reinforcement phase in step S4 is as follows:
[0025] S41: Calculate the center O of the i-th network plane i (X i , Y i , Z i ):
[0026]
[0027] Where: ∑V i,j is the node coordinates and NV of the i-th network plane i is the number of nodes in the network plane;
[0028] S42: Calculate a new plane based on the i-th network plane:
[0029] Extract all edges of the i-th network plane and point them towards the center O of the network plane. i Translate the length of the radius of the circumscribed circle of the section of the XOY plane; the figure enclosed by the translated edge is the new plane Si_new;
[0030] S43: Generate N in the new plane Si_new i points, and the distance between any two points is not less than the length of the radius of the cross-section circumscribed circle of the two XOY planes; the generated N i The coordinate positions of the points are taken as the first set Set-Node i , respectively represent the position of the convex polyhedron reinforcement phase in the network plane.
[0031] Preferably, the specific steps of establishing the geometric model of the quasi-continuous network composite material in step S5 are as follows:
[0032] S51: Calculate the rotation axis Raxis of the convex polyhedron reinforcement phase in the i-th network plane:
[0033] Raxis=(VN i +Zaxis) / 2
[0034] Where: VN i is the normal vector of the i-th network plane, and Zaxis is the unit vector in the Z direction of the network plane;
[0035] S52: With the rotation axis Raxis as the axis, the convex polyhedron reinforcement phase is spatially rotated with a rotation angle of 180° to obtain a new convex polyhedron reinforcement phase Polyhedron_i;
[0036] S53: According to the first set Set-Node i The coordinate position of each point in the network is used to move the new convex polyhedron reinforcement phase Polyhedron_i from the Cartesian coordinate system origin O(0,0,0), and insert the convex polyhedron reinforcement phase into the i-th network plane;
[0037] S54: Repeat steps S51 to S53, insert convex polyhedron reinforcement phases into all network planes, and gather all convex polyhedron reinforcement phases into the second set REINFORCEMENT to obtain the reinforcement phase geometric model of the composite material; draw a cube with the Cartesian coordinate system origin O(0, 0, 0) and point (L, L, L) as the minimum and maximum points respectively to obtain the matrix geometric model; assemble the reinforcement phase geometric model and the matrix geometric model of the composite material to obtain a quasi-continuous network composite material geometric model.
[0038] Preferably, the mesh type in the mesh division in step S6 is a 4-node tetrahedron unit, and the total number of mesh units is not less than 700,000.
[0039] Preferably, the cooling boundary conditions in step S6 are set as follows: the high temperature T1 is not greater than 1200°C, the low temperature T0 is not lower than -100°C, and the cooling rate ΔT is 80-120°C.
[0040] Preferably, in step S6, finite element software ABAQUS is used to perform numerical simulation.
[0041] Compared with the prior art, the present invention has the following beneficial effects:
[0042] (1) The method provided by the present invention effectively solves the problem of difficulty in establishing geometric models of quasi-continuous composite materials. The method has low modeling difficulty, simple steps, and can support different types of reinforcement phase shapes.
[0043] (2) The present invention uses simulation technology to predict the thermal residual stress distribution of a quasi-continuous composite material geometric model. The method provided by the present invention can generate distributed particle shapes, and high-throughput calculations can establish the relationship between the enhanced phase space distribution characteristics and the thermal residual stress distribution. BRIEF DESCRIPTION OF THE DRAWINGS
[0044] Figure 1 The geometric model of the convex polyhedron reinforcement phase established in Example 1;
[0045] Figure 2The mesh structure geometric model established in Example 1;
[0046] Figure 3 is the geometric model of the quasi-continuous network composite material obtained in Example 1;
[0047] Figure 4 This is a cloud diagram of the thermal residual stress simulation of the quasi-continuous network composite material in Example 1. DETAILED DESCRIPTION
[0048] 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.
[0049] The present invention provides a method for predicting thermal residual stress of a quasi-continuous network composite material. The specific method is as follows:
[0050] 1. Establish the geometric model of convex polyhedron reinforcement phase.
[0051] In 3D modeling software, a geometric model of the convex polyhedron reinforcement phase was constructed based on its geometric parameters. These parameters include the volume VP of the convex polyhedron and the radius RP of the circumcircle of its cross section in the XOY plane. The resulting convex polyhedron reinforcement phase possesses the following characteristics: its center is the Cartesian origin O(0, 0, 0), the convex polyhedron reinforcement phase is mirror-symmetric about the XOY plane, and it exhibits even-numbered rotational symmetry about the Z axis.
[0052] It should be noted that the 3D modeling software can be AutoCAD, CINEMA 4D, SolidWorks, NX, Rhinoceros, MAYA, 3DMAX or Blender software.
[0053] 2. Establish a mesh structure geometric model.
[0054] In commercial software or an open-source software package, set the mesh parameters and establish a mesh geometry model. The mesh geometry model must have the following characteristics: the number of mesh plane edges must be at least 4, the internal angles of the mesh plane must be at least 90°, and the average aspect ratio of the mesh plane must be no greater than 2:1.
[0055] It should be noted that commercial software can be AutoCAD, CINEMA 4D, Rhinoceros or MATLAB, and open source software packages can be Blender, Neper or Scipy.
[0056] 3. Calculate the number of convex polyhedron reinforcement phases that the network plane can accommodate.
[0057] (1) Calculate the total number N of convex polyhedral reinforcement phases:
[0058]
[0059] Where: VF is the volume fraction of the convex polyhedron reinforcement phase; VP is the volume of the convex polyhedron reinforcement phase; L is the model size.
[0060] Perform the following operations on each network plane:
[0061] (2) Calculate the area ratio sr of the i-th network plane in the mesh structure geometric model i :
[0062]
[0063] Where: S i is the area of the ith network plane, S net is the total area of the mesh structure geometric model;
[0064] (3) Calculate the number N of convex polyhedron reinforcement phases that can be accommodated by the i-th network plane i =N×sr i .
[0065] 4. Calculate the position of the convex polyhedron reinforcement phase in the network plane.
[0066] Perform the following operations on all network planes of the mesh structure geometric model:
[0067] (1) Calculate the center O of the i-th network plane i (X i , Y i , Z i ):
[0068]
[0069] Where: ∑V i,j is the node coordinates and NV of the i-th network plane i is the number of nodes in the network plane;
[0070] (2) Calculate the new plane based on the i-th network plane:
[0071] Extract all edges of the i-th network plane and point them towards the center O of the network plane. i Translate the length RP of the radius of the circumscribed circle of a cross section; the figure enclosed by the translated edge is the new plane Si_new;
[0072] (3) Randomly generate N in the new plane Si_new i points, and the distance between any two points is not less than the length RP of the radius of the circumscribed circle of the two sections; the generated N iThe coordinate positions of the points are taken as the first set Set-Node i , respectively represent the position of the convex polyhedron reinforcement phase in the network plane.
[0073] 5. Establish a quasi-continuous network composite material geometric model.
[0074] Perform the following operations on all network planes of the mesh structure geometric model:
[0075] (1) Calculate the rotation axis Raxis of the convex polyhedron reinforcement phase in the i-th network plane:
[0076] Raxis=(VN i +Zaxis) / 2
[0077] Where: VN i is the normal vector of the i-th network plane, and Zaxis is the unit vector in the Z direction of the network plane;
[0078] (2) Perform spatial rotation on the convex polyhedron reinforcement phase in the i-th network plane.
[0079] With the rotation axis Raxis as the axis, the convex polyhedron reinforcement phase is spatially rotated with a rotation angle of 180° to obtain a new convex polyhedron reinforcement phase Polyhedron_i;
[0080] (3) Perform convex polyhedron enhancement phase insertion on the i-th network plane.
[0081] According to the first set Set-Node i The coordinate position of each point in the convex polyhedron is respectively moved from the Cartesian coordinate system origin O(0,0,0) to insert the convex polyhedron reinforcement phase into the i-th network plane. In other words, the new convex polyhedron reinforcement phase Polyhedron_i is inserted into the convex polyhedron_i according to the first set Set-Node i The coordinate position in the vector is moved.
[0082] For example, the first set Set-Node i There are two coordinate positions (1, 1, 1) and (2, 2, 2), so the two new convex polyhedron enhancement phases are translated from the origin O(0, 0, 0) by (1, 1, 1) and (2, 2, 2) respectively.
[0083] (4) Repeat steps (1) to (2), insert convex polyhedral reinforcement phases into all network planes, and collect all convex polyhedral reinforcement phases into the second set REINFORCEMENT to obtain the reinforcement phase geometric model of the composite material.
[0084] Draw a cube with the Cartesian origin O(0,0,0) and the point (L,L,L) as the minimum and maximum points, respectively, to obtain the base geometry model. In other words, the nodes of this cube are (0,0,0) and (L,L,L), and the faces of the cube are parallel to the XOY, YOZ, and ZOX planes, respectively.
[0085] The reinforcement phase geometric model and the matrix geometric model of the composite material are assembled to obtain a quasi-continuous network composite material geometric model.
[0086] 6. Grid division and boundary condition setting.
[0087] The resulting quasi-continuous mesh composite geometry was meshed using a 4-node tetrahedral mesh with a minimum of 700,000 elements. The high temperature T1, low temperature T0, and cooling rate ΔT were set as cooling boundary conditions. The temperature field of the quasi-continuous mesh composite geometry was reduced from T1 to T0 over (TT) / ΔT calculation steps. The (0, 0, 0) node of the constraint model remained motionless and rotational during the simulation.
[0088] 7. Finite element simulation.
[0089] Finite element software ABAQUS is used to input material properties and perform numerical simulation on the thermal mismatch behavior of quasi-continuous network composite materials during cooling process, and the thermal residual stress distribution of quasi-continuous network composite materials is obtained.
[0090] The following will illustrate the practical application effects of the above method of the present invention through specific examples.
[0091] Example 1
[0092] 1. Establish the geometric model of convex polyhedron reinforcement phase.
[0093] The convex polyhedron created is a hexagonal prism, which is symmetrical about the Z axis for 6 rotations, such as Figure 1 The volume of the convex polyhedron reinforcement phase is VP = 47.0, and the radius of the circumscribed circle of the cross section in the XOY plane is RP = 0.97.
[0094] 2. Establish a mesh structure geometric model.
[0095] The model size is L = 100, the number of mesh cells is 24, and the network plane angle is bimodal distribution, concentrated at 60° and 120°, as shown in the following example: Figure 2 shown.
[0096] 3. Set the volume fraction of the convex polyhedron reinforcement phase VF = 10%, and calculate the number of convex polyhedron reinforcement phases that can be accommodated on the network plane.
[0097] 4. Based on the number of convex polyhedral reinforcement phases obtained in step 3, calculate the position of the reinforcement phase in the network plane.
[0098] 5. Establish the geometric model of quasi-continuous network composite material. The obtained geometric model of quasi-continuous network composite material is as follows Figure 3 shown.
[0099] 6. Meshing and Cooling Boundary Conditions. A quasi-continuous mesh composite geometry model was meshed using 4-node tetrahedral elements with a total of 1,000,000 elements. The model was set to a high temperature of T1 = 500°C, a low temperature of T0 = 380°C, and a cooling rate of ΔT = 120°C.
[0100] 7. Using the commercial finite element software ABAQUS, inputting material properties, numerically simulate the thermal mismatch behavior of the quasi-continuous network composite material during the cooling process to obtain the thermal residual stress distribution of the quasi-continuous network composite material.
[0101] The relationship between the material's Young's modulus (E), Poisson's ratio (λ), and expansion coefficient (α) and temperature is set as follows:
[0102]
[0103]
[0104] This example establishes a finite element model of a composite material with hexagonal whisker reinforcements. The model is relatively complex, with the whiskers oriented in the plane of the network layer. Figure 4 The residual stress distribution of the matrix is shown in a cross-sectional diagram at X=50. It can be seen that the thermal residual stress distribution of the composite material is well predicted. The stress level in the reinforcement phase aggregation area is higher than 75MPa, and the residual stress increases sharply as the reinforcement phase spacing decreases. However, the residual stress level in the reinforcement phase aggregation area decreases sharply, and in the area far away from the reinforcement phase, the stress level drops to ~10MPa. It can be seen that the model established by the method provided by the present invention can effectively predict the thermal residual stress distribution of quasi-continuous composite materials with complex structures.
[0105] 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 quasi-continuous network composite material, characterized in that: The specific steps are as follows: S1: In the 3D modeling software, a geometric model of the convex polyhedron reinforcement phase is established according to the geometric parameters of the convex polyhedron reinforcement phase; S2: Set mesh structure parameters and establish mesh structure geometric model; S3: setting the volume fraction of the convex polyhedron reinforcement phase, and calculating the number of convex polyhedron reinforcement phases accommodated in the network plane based on the network structure geometric model obtained in step S2; S4: Based on the number of convex polyhedral reinforcement phases accommodated in the network plane calculated in step S3, the position of the convex polyhedral reinforcement phase is calculated; S5: Based on the position of the convex polyhedron reinforcement phase obtained in step S4, the convex polyhedron reinforcement phase geometric model established in step S1 is inserted into the plane of all the network structure geometric models to obtain a quasi-continuous network composite material geometric model; S6: Meshing the geometric model of the quasi-continuous network composite material obtained in step S5 and applying cooling boundary conditions; inputting material properties, performing numerical simulation on the thermal mismatch behavior of the quasi-continuous network composite material during the cooling process, and obtaining the thermal residual stress distribution of the quasi-continuous network composite material; The network plane in step S3 accommodates the number N of convex polyhedron enhancement phases i The calculation method is as follows: S31: Calculate the total number N of convex polyhedral reinforcement phases: Where: VF is the volume fraction of the convex polyhedron reinforcement phase; VP is the volume of the convex polyhedron reinforcement phase; L is the model size; S32: Calculate the area ratio sr of the i-th network plane in the mesh structure geometric model i : Where: S i is the area of the ith network plane, S net is the total area of the mesh structure geometric model; S33: Calculate the number N of convex polyhedron enhancement phases accommodated by the i-th network plane i =N×sr i ; The specific method for calculating the position of the convex polyhedron reinforcement phase in step S4 is as follows: S41: Calculate the center O of the i-th network plane i (X i , Y i , Z i ): Where: ∑V i,j is the node coordinates and NV of the i-th network plane i is the number of nodes in the network plane; S42: Calculate a new plane based on the i-th network plane: Extract all edges of the i-th network plane and point them towards the center O of the network plane. i Translate the length of the radius of the circumscribed circle of the section of the XOY plane; the figure enclosed by the translated edge is the new plane Si_new; S43: Generate N in the new plane Si_new i points, and the distance between any two points is not less than the length of the radius of the cross-section circumscribed circle of the two XOY planes; the generated N i The coordinate positions of the points are taken as the first set Set-Node i , respectively represent the position of the convex polyhedron reinforcement phase in the network plane; The specific steps for establishing the geometric model of the quasi-continuous network composite material in step S5 are as follows: S51: Calculate the rotation axis Raxis of the convex polyhedron reinforcement phase in the i-th network plane: Raxis=(VN i +Zaxis) / 2 Where: VN i is the normal vector of the i-th network plane, and Zaxis is the unit vector in the Z direction of the network plane; S52: With the rotation axis Raxis as the axis, the convex polyhedron reinforcement phase is spatially rotated with a rotation angle of 180° to obtain a new convex polyhedron reinforcement phase Polyhedron_i; S53: According to the first set Set-Node i The coordinate position of each point in the network is used to move the new convex polyhedron reinforcement phase Polyhedron_i from the Cartesian coordinate system origin O(0,0,0), and insert the convex polyhedron reinforcement phase into the i-th network plane; S54: Repeat steps S51 to S53, insert convex polyhedron reinforcement phases into all network planes, and gather all convex polyhedron reinforcement phases into the second set REINFORCEMENT to obtain the reinforcement phase geometric model of the composite material; draw a cube with the Cartesian coordinate system origin O(0, 0, 0) and point (L, L, L) as the minimum and maximum points respectively to obtain the matrix geometric model; assemble the reinforcement phase geometric model and the matrix geometric model of the composite material to obtain a quasi-continuous network composite material geometric model.
2. The method for predicting thermal residual stress of a quasi-continuous network composite material according to claim 1, characterized in that: The geometric parameters of the convex polyhedron reinforcement phase in step S1 include the volume of the convex polyhedron and the radius of the circumscribed circle of the cross section of the XOY plane; the center point of the convex polyhedron reinforcement phase is the origin of the Cartesian coordinate system O(0, 0, 0), and the convex polyhedron reinforcement is mirror-symmetrical with respect to the XOY plane and has an even number of rotational symmetry about the Z axis.
3. The method for predicting thermal residual stress of a quasi-continuous network composite material according to claim 1, characterized in that: The number of network plane edges of the mesh structure geometric model in step S2 is not less than 4, the internal angle of the network plane is not less than 90°, and the average aspect ratio of the network plane is not higher than 2:
1.
4. The method for predicting thermal residual stress of a quasi-continuous network composite material according to claim 1, characterized in that: The mesh structure parameters in step S2 include model size, number of mesh cells and angular distribution of average angles of network planes.
5. The method for predicting thermal residual stress of a quasi-continuous network composite material according to claim 1, characterized in that: The mesh type in the mesh division described in step S6 is a 4-node tetrahedron unit, and the total number of mesh units is not less than 700,000.
6. The method for predicting thermal residual stress of a quasi-continuous network composite material according to claim 1, characterized in that: The cooling boundary conditions in step S6 are set as follows: the high temperature T1 is not greater than 1200°C, the low temperature T0 is not less than -100°C, and the cooling rate ΔT is 80-120°C.
7. The method for predicting thermal residual stress of a quasi-continuous network composite material according to claim 1, characterized in that: In step S6, the finite element software ABAQUS is used to perform numerical simulation.