A method for constructing a stiffness equivalent model of a porous laminated structural member

Abstract

This invention provides a method for constructing a stiffness equivalent model of a porous laminated structural member, including: S1, obtaining the unit cell characteristic size parameters of the pores on the laminates; S2, constructing a unit cell solid model of the laminates; S3, constructing a unit cell solid finite element analysis model of the laminates; S4, preprocessing the unit cell solid finite element analysis model; S5, calculating the stiffness equivalent modulus of the laminates at different temperatures; S6, repeating steps S1 to S5 to calculate the stiffness equivalent modulus of all laminates in the porous laminated structural member in each direction at different temperatures; S7, performing integrated boundary processing on the stiffness equivalent modulus calculated in step S6 to construct the stiffness equivalent model of the porous laminated structural member. This method can simplify porous laminated structural members into non-porous laminated structural models, effectively reflecting the mechanical properties of porous laminated structural members, while significantly improving computational efficiency and accuracy, and has broad engineering application prospects.

Description

Technical Field

[0001] This invention belongs to the field of aero-engines and relates to the design technology of stiffness equivalent model of perforated components, specifically to a method for constructing a stiffness equivalent model of a porous laminated structural component. Background Technology

[0002] Some components in aero-engines, such as turbine blades, flame tubes, and heat shields, contain numerous fine pores with a diameter not exceeding 1 mm, and the total area of ​​these pores accounts for more than 50% of the total area of ​​the component. When performing conventional finite element analysis on these components, retaining the structural features of these pores makes mesh generation extremely difficult and time-consuming when constructing the component's computational model, resulting in a massive number of meshes, reaching millions, leading to low computational efficiency and difficulty in simulating real-world usage scenarios. Conversely, ignoring the pore structure simplifies the component's computational model, but the computational accuracy cannot meet engineering requirements and cannot accurately reflect the component's true condition under operating conditions.

[0003] Therefore, it is necessary to improve the computational model construction method for components with fine holes. Summary of the Invention

[0004] To address the problems of existing methods in finite element analysis of porous components in aero-engines, such as difficulty in simulating real-world usage scenarios, low accuracy, and low reliability of calculation results, this invention discloses a method for constructing a stiffness equivalent model of porous laminated structural components. This method, a "stiffness equivalence" approach, simplifies porous laminated structural components into non-porous laminated structural models, effectively reflecting the mechanical properties of porous laminated structural components while significantly improving computational efficiency and accuracy, thus possessing broad engineering application prospects.

[0005] The technical solution to achieve the purpose of the invention is as follows: A method for constructing an equivalent stiffness model of a porous laminated structural member, wherein the porous laminated structural member includes multiple layers, and the method for constructing an equivalent stiffness model of the porous laminated structural member includes the following steps:

[0006] S1. Obtain the unit cell feature size parameters of the fine pores on the layer plate;

[0007] S2, unit cell feature size parameters, construct the unit cell solid model of the layer plate;

[0008] S3. Mesh the unit cell solid model and construct the unit cell solid finite element analysis model of the layer plate;

[0009] S4. Apply load performance parameters, temperature, and constraints to the unit cell finite element analysis model and perform preprocessing.

[0010] S5. Calculate the equivalent stiffness modulus of the upper plate at different temperatures;

[0011] S6. Repeat steps S1 to S5 to calculate the equivalent stiffness modulus of all layers in the porous laminated structure in each direction at different temperatures.

[0012] S7. Perform integrated boundary processing on the stiffness equivalent modulus calculated in step S6 to construct the stiffness equivalent model of the porous laminated structure component.

[0013] Further, in step S1, the method for obtaining the unit cell characteristic size parameters of the pores on the layer plate includes:

[0014] S11. Construct a structural model of the layer plate and determine the pore distribution pattern of the layer plate based on the pore diameter;

[0015] S12. Based on the distribution pattern of fine pores, obtain the unit cell characteristic size parameters of the fine pores on the layer plate.

[0016] Furthermore, in step S12, the unit cell characteristic size parameters include the pore radius, the lateral distance between the centers of two adjacent pores, the longitudinal distance between the centers of two adjacent pores, and the layer thickness; wherein, two adjacent pores refer to two pores with the same diameter.

[0017] Furthermore, in step S3, when the unit cell solid model is meshed, the mesh type is tetrahedral mesh element or hexahedral mesh element, and the hole edge position in the unit cell solid model is finely divided during meshing.

[0018] Furthermore, in step S2, if there are ≥2 sizes of unit cell solid models in the layer, then in step S3, the unit cell solid models of each size are separately meshed to construct unit cell solid finite element analysis models, and then combined to form the unit cell solid model of the layer.

[0019] Furthermore, in step S4, the performance parameters are material performance parameters, and the constraints are boundary constraints and load constraints.

[0020] Furthermore, in step S5, the method for calculating the equivalent stiffness modulus of the upper plate at different temperatures includes:

[0021] S51. Extract the stress and strain of each mesh element in each direction in the finite element analysis model of a single-cell solid at different temperatures.

[0022] S52. Calculate the product of stress and strain in each direction of each mesh element and the mesh element volume, sum them and divide by the total mesh element volume to obtain the equivalent stress and equivalent strain of the unit cell finite element analysis model.

[0023] S53. Calculate the equivalent stiffness modulus of the plate based on equivalent stress and equivalent strain.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: The method for constructing the stiffness equivalent model of porous laminated structural components provided by the present invention is a "stiffness equivalence" method. This method simplifies the stiffness equivalent model of porous laminated structural components with a large number of fine pores, reduces the difficulty of analysis, improves the calculation efficiency, and improves the accuracy and reliability of the analysis results. It provides theoretical support and provides basic support for the design and analysis of porous laminated structures in aero-engines, and has engineering application prospects.

[0025] Meanwhile, the method of this invention can reduce the number of meshes in finite element analysis by more than 70% compared to the original model, saving more than 80% of the computational analysis time. During the analysis, the application of material property parameters with equivalent stiffness modulus better reflects the mechanical properties of the original porous laminated structure, thus improving computational accuracy. The method of this invention has been successfully applied to the finite element analysis of a porous laminated structure component of a certain type of engine, and a complete analysis process has been established based on this. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0027] Figure 1 This is a flowchart of the method for constructing the stiffness equivalent model of the porous laminated structure component of the present invention;

[0028] Figure 2 This is a schematic diagram showing the distribution of fine holes on the layer plate in a specific embodiment;

[0029] Figure 3 This is a schematic diagram of the finite element analysis model of a single-cell solid model of a porous laminated structural component after meshing, as shown in a specific embodiment. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0031] This specific implementation method constructs a stiffness equivalent model for porous laminated structural components including multiple layers, which provides basic support for the analysis of some multi-layered components with a large number of fine pores in aero-engines. It should be noted that layers with the same fine pore distribution pattern among multiple layers can be regarded as the same layer.

[0032] See Figure 1 As shown in the figure, this specific embodiment discloses a method for constructing a stiffness equivalent model of a porous laminated structural member, including the following steps:

[0033] S1. Obtain the unit cell feature size parameters of the fine pores on the layer plate;

[0034] S2, unit cell feature size parameters, construct the unit cell solid model of the layer plate;

[0035] S3. Mesh the unit cell solid model and construct the unit cell solid finite element analysis model of the layer plate;

[0036] S4. Apply load performance parameters, temperature, and constraints to the unit cell finite element analysis model and perform preprocessing.

[0037] S5. Calculate the equivalent stiffness modulus of the upper plate at different temperatures;

[0038] S6. Repeat steps S1 to S5 to calculate the equivalent stiffness modulus of all layers in the porous laminated structure in each direction at different temperatures.

[0039] S7. Perform integrated boundary processing on the stiffness equivalent modulus calculated in step S6 to construct the stiffness equivalent model of the porous laminated structure component.

[0040] The following specific examples illustrate each step in the above method for constructing the stiffness equivalent model:

[0041] In one embodiment, step S1, the method for obtaining the unit cell feature size parameters of the pores on the layer plate, includes:

[0042] S11. Construct a structural model of the layer plate and determine the pore distribution pattern of the layer plate based on the pore diameter;

[0043] S12. Based on the distribution pattern of fine pores, obtain the unit cell characteristic size parameters of the fine pores on the layer plate;

[0044] Among them, the characteristic size parameters of the unit cell include the pore radius, the lateral distance between the centers of two adjacent pores, the longitudinal distance between the centers of two adjacent pores, and the thickness of the layer; where two adjacent pores refer to two pores with the same diameter.

[0045] It should be noted here that, see Figure 2 As shown, the same layer may contain one or more types of pores. For each type of pore, the unit cell characteristic size parameter needs to be calculated separately.

[0046] In one embodiment, in step S2, the unit cell solid model is constructed using geometric modeling software such as CAD or UG, based on the unit cell feature size parameters.

[0047] It should be noted that when there are ≥2 sizes of unit cell solid models in the layer, in step S3, the unit cell solid finite element analysis model is constructed separately for each size of unit cell solid model, and then combined to form the unit cell solid model of the layer.

[0048] In one embodiment, in step S3, the finite element analysis model of the single-cell solid of the plate is generated by importing the single-cell solid model into meshing software such as ANSA and Hypermesh, and then meshing it using 10-node tetrahedral elements or 20-node hexahedral elements.

[0049] It should be noted that, to ensure solution efficiency and accuracy, the mesh of the unit cell solid model should not be too large or too small, and at least two mesh layers should be maintained in the thickness direction of the layer. Furthermore, the mesh at the hole edges in the unit cell solid model should be refined; typically, the number of mesh elements at the hole edges should not be less than 20. For this specific implementation, see [link to implementation details]. Figure 3 The diagram shows a schematic of the finite element analysis model of a unit cell solid model formed by finite element meshing of one of the layers of a porous laminated structure component.

[0050] In one embodiment, the constructed unit cell finite element analysis model needs to be preprocessed, that is, in step S4, the load performance parameters, temperature and constraints of the unit cell finite element analysis model are preprocessed, wherein the performance parameters are material performance parameters and the constraints are boundary constraints and load constraints.

[0051] It should be noted that since the material properties are different at different temperatures, the correspondence between the material properties and temperature must be ensured when preprocessing the finite element analysis model of the unit cell.

[0052] When boundary constraints and load constraints are applied, the lateral distance between the centers of two adjacent fine holes and the longitudinal distance between the centers of two adjacent fine holes are not necessarily equal. Therefore, the internal mechanical properties of the unit cell finite element analysis model in the xy plane may exhibit anisotropy, i.e., E x ≠E y In terms of the unit cell microstructure, due to its three orthogonal planes of symmetry, the equivalent material is an orthotropic material, and the independent engineering material variables are E. xx E yy E zz G xy G xz G yz E xx E is the elastic modulus in the x-direction of a hexahedral mesh element. yy E is the elastic modulus in the y-direction of a hexahedral mesh element. zzG is the elastic modulus in the z-direction of a hexahedral mesh element. xy G is the shear modulus of the hexahedral mesh element in the xy plane. xz G is the shear modulus of the xz plane of a hexahedral mesh element. yz This is the shear modulus of the yz plane of a hexahedral mesh element.

[0053] In solving E xx At that time, the unit cell constraint boundary condition is to constrain one side of the unit cell in the x direction, and apply a forced displacement of 0.1 mm to the other side; the constraint on one side of the two sides in the y and z directions is 0, and the other side maintains the same deformation, with displacement coupling constraint applied. E zz E yy G xy G xz G yz The constraint boundary and E xx The constraint boundaries are similar. It should be noted that the material property parameters at different temperatures need to be calculated separately. The model is the same, but the material properties are different, so they need to be solved separately.

[0054] In one embodiment, step S5, the method for calculating the equivalent stiffness modulus of the upper plate at different temperatures, includes:

[0055] S51. At different temperatures, extract the stress σ in each direction of each mesh element in the finite element analysis model of the unit cell solid. ij (x) and strain ε ij (x):

[0056] S52. Calculate the product of stress and strain in each direction of each mesh element and the mesh element volume, sum them, and divide by the total mesh element volume to obtain the equivalent stress of the unit cell finite element analysis model. and equivalent strain

[0057] S53. Based on equivalent stress and equivalent strain, calculate the equivalent stiffness modulus of the laminate, i.e.

[0058]

[0059] Where σ(x) is the material's micro-stress, and ε(x) is the material's micro-strain; Ω X Let x represent the region occupied by the volume element at position x, v be the volume of the mesh element, and x be the mesoscopic coordinate. The stiffness equivalent modulus is the stiffness equivalent model of a porous laminated structural member.

[0060] Through steps S1 to S5, the equivalent stiffness modulus of all layers in the porous laminated structure in each direction at different temperatures can be calculated. When analyzing the entire porous laminated structure, the equivalent stiffness modulus of each layer is used to perform integrated boundary treatment, thereby constructing the equivalent stiffness model of the porous laminated structure.

[0061] The stiffness equivalent model construction method for porous laminated structural components provided in this specific embodiment is a "stiffness equivalence" method. This method simplifies the stiffness equivalent model of porous laminated structural components with a large number of fine pores, reduces the analysis difficulty, improves the calculation efficiency, and enhances the accuracy and reliability of the analysis results. It provides theoretical support and basic support for the design and analysis of porous laminated structures in aero-engines, and has engineering application prospects.

[0062] Meanwhile, the method of this invention can reduce the number of meshes in finite element analysis by more than 70% compared to the original model, saving more than 80% of the computational analysis time. During the analysis, the application of material property parameters with equivalent stiffness modulus better reflects the mechanical properties of the original porous laminated structure, thus improving computational accuracy. The method of this invention has been successfully applied to the finite element analysis of a porous laminated structure component of a certain type of engine, and a complete analysis process has been established based on this.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0064] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for constructing an equivalent stiffness model for a porous laminated structural member, characterized in that, Porous laminated structural members consist of multiple layers. The method for constructing the stiffness equivalent model of porous laminated structural members includes the following steps: S1. Obtain the unit cell feature size parameters of the fine pores on the layer plate; S2, unit cell feature size parameters, construct the unit cell solid model of the layer plate; S3. Mesh the unit cell solid model and construct the unit cell solid finite element analysis model of the layer plate; S4. Apply load performance parameters, temperature, and constraints to the unit cell finite element analysis model to ensure the correspondence between material performance parameters and temperature. S5. Calculate the equivalent stiffness modulus of the laminate at different temperatures, including: S51. Extracting the stress and strain of each mesh element in each direction in the unit cell finite element analysis model at different temperatures; S52. Calculating the product of the stress and strain in each direction of each mesh element with the volume of the mesh element, summing the products and dividing by the total volume of the mesh elements to obtain the equivalent stress and equivalent strain of the unit cell finite element analysis model; S53. Calculating the equivalent stiffness modulus of the laminate based on the equivalent stress and equivalent strain. S6. Repeat steps S1 to S5 to calculate the equivalent stiffness modulus of all layers in the porous laminated structure in each direction at different temperatures. S7. Perform integrated boundary processing on the stiffness equivalent modulus calculated in step S6 to construct the stiffness equivalent model of the porous laminated structure component.

2. The method for constructing a stiffness equivalent model according to claim 1, characterized in that, In step S1, the method for obtaining the unit cell characteristic size parameters of the pores on the layer includes: S11. Construct a structural model of the layer plate and determine the pore distribution pattern of the layer plate based on the pore diameter; S12. Based on the distribution pattern of fine pores, obtain the unit cell characteristic size parameters of the fine pores on the layer plate.

3. The method for constructing a stiffness equivalent model according to claim 2, characterized in that, In step S12, the unit cell characteristic size parameters include the pore radius, the lateral distance between the centers of two adjacent pores, the longitudinal distance between the centers of two adjacent pores, and the layer thickness; wherein, two adjacent pores refer to two pores with the same diameter.

4. The method for constructing a stiffness equivalent model according to claim 1, characterized in that, In step S3, when the unit cell solid model is meshed, the mesh type is tetrahedral mesh element or hexahedral mesh element, and the hole edge positions in the unit cell solid model are refined during meshing.

5. The method for constructing a stiffness equivalent model according to claim 1, characterized in that, In step S2, if there are ≥2 sizes of unit cell solid models in the layer, then in step S3, the unit cell solid models of each size are separately meshed to construct unit cell solid finite element analysis models, and then combined to form the unit cell solid model of the layer.

6. The method for constructing a stiffness equivalent model according to claim 1, characterized in that, In step S4, the performance parameters are material performance parameters, and the constraints are boundary constraints and load constraints.

Images