CN-122021155-A - Topology optimization method, system, equipment and storage medium of lattice structure

CN122021155ACN 122021155 ACN122021155 ACN 122021155ACN-122021155-A

Abstract

The invention relates to the technical field of topological optimization of lattice structures, and discloses a topological optimization method, a system, equipment and a storage medium of a lattice structure. The method comprises the steps of firstly establishing a target index containing a topological layer, a spatial layer and a mapping table according to an initial design domain or an initial lattice model of a target to be optimized, executing multi-physical-field sensitivity analysis based on the target index and a preset boundary condition to obtain geometrical parameters and topology existence sensitivity data, generating a priority queue according to a sensitivity absolute value, sequentially executing topology reconstruction and geometrical form optimization, updating physical fields and sensitivity data in a first-order neighborhood of an operation object after an optimization task is completed, incrementally maintaining the target index until convergence conditions are met to obtain a lattice topology framework, and outputting a standard additive manufacturing file and a lattice metadata text report through geometrical entity reconstruction, topology validity verification and additive manufacturing technology constraint verification. The invention realizes high-efficiency and high-precision topology optimization under the condition of limited resources, and combines structural performance and manufacturability.

Inventors

ZHANG KAIXIANG
LI XIN
JIA XINJIAN
LIU BINGSHAN
WANG GONG

Assignees

中国科学院空间应用工程与技术中心

Dates

Publication Date: 20260512
Application Date: 20260128

Claims (10)

1. A method for topology optimization of a lattice structure, comprising: Establishing a target index according to an initial design domain or an initial lattice model of a target to be optimized, wherein the target index comprises a topology layer, a space layer and a mapping table, the topology layer is used for representing the connection relation between nodes in the target to be optimized and structural units, and the space layer is used for representing the space position information of the nodes in the target to be optimized; Based on the target index, performing multi-physical field sensitivity analysis on the target to be optimized according to a preset boundary condition, obtaining full-field physical response data and converting the full-field physical response data into sensitivity data, wherein the sensitivity data comprises geometric parameter sensitivity and topology existence sensitivity; Generating a priority queue according to the absolute value of the sensitivity data, wherein the priority queue comprises a plurality of optimization tasks which are arranged in sequence, and performing topology reconstruction and geometry optimization operations on the target to be optimized according to a queue sequence to obtain a lattice structure intermediate model; Updating physical field distribution and sensitivity data in a first-order neighborhood of an operation object of an optimization task aiming at the lattice structure intermediate model after each optimization task is completed, and maintaining the target index in a synchronous increment mode until a preset convergence condition is met, so as to obtain a lattice topology framework; And carrying out geometric entity reconstruction, topology effectiveness verification and additive manufacturing process constraint verification on the lattice topology framework, and outputting a standard additive manufacturing file and a lattice metadata text report corresponding to the target to be optimized.
2. The method of claim 1, wherein the topology layer of the target index adopts a half-side data structure centered on a vertex, only represents the connection relation between a node and a structural unit, each half-side object stores a dual side, a starting point and a next side pointer surrounding the starting point, and the structural unit comprises a micro rod piece and a wallboard; The space layer adopts a pointer-free linear octree, the space position information of the nodes is flattened and stored in a continuous memory, and the parent-child node relation is established through Morton codes or integer indexes; The mapping table comprises a first mapping table from a space position to a topology logic and a second mapping table from the topology logic to the space position, and the first mapping table and the second mapping table are used for realizing real-time bidirectional indexing of a topology layer and a space layer.
3. The method of claim 1, wherein the predetermined boundary conditions include load conditions, thermal boundary conditions, and displacement constraints, wherein performing a multi-physical field sensitivity analysis on the object to be optimized according to the predetermined boundary conditions based on the object index, obtaining full-field physical response data and converting the full-field physical response data into sensitivity data comprises: based on the discrete lattice diagram structure related to the target index, a beam unit or truss unit is adopted to construct a global stiffness matrix and a heat conduction matrix, a balance equation is solved by combining the preset boundary condition, and key physical quantities of full-field node displacement, temperature distribution and structural units are obtained, wherein the key physical quantities comprise von mises stress, strain energy density, heat flux modulus and node counterforce; Determining geometrical parameter sensitivities based on the key physical quantities, wherein the geometrical parameter sensitivities comprise structural unit section sensitivities and node position sensitivities, the structural unit section sensitivities are derivatives of unit strain energy to structural unit section radii, and the node position sensitivities are gradients of system flexibility to node space coordinates; And determining topology existence sensitivity based on the key physical quantity, wherein the topology existence sensitivity comprises an additive threshold and a subtractive threshold, the additive threshold and the subtractive threshold are set through the average energy density or stress concentration coefficient of a local area, the topology existence sensitivity is used for dividing an area with the topology existence sensitivity higher than the additive threshold into topology subdivision demand areas, and dividing an area with the topology existence sensitivity lower than the subtractive threshold into topology redundant areas.
4. The method of claim 1, wherein generating a priority queue from the absolute value of the sensitivity data and performing topology reconstruction and geometry optimization operations comprises: taking the absolute value of the sensitivity data as a sequencing key value, and sequentially sequencing a plurality of optimization tasks from large to small to obtain the priority queue; Allocating a unique version number to each node and each structural unit in the target to be optimized, and increasing the version number corresponding to any node or any structural unit when any node or any structural unit is modified; Ejecting an optimization task from the front end of the priority queue, comparing the version number of the node or the structural unit recorded by the task with the current version number, judging that the task is invalid and discarding if the version number is inconsistent with the current version number, and determining that the task is an effective optimization task if the version number is consistent with the current version number; aiming at the effective optimization task, according to the type of the sensitivity data, corresponding topological structure reconstruction or geometric form optimization operation execution is scheduled, and targeted optimization of the point array structure is completed.
5. The method of claim 4, wherein performing topology reconstruction and geometry optimization operations comprises performing a geometry optimization operation of local movement of nodes or radial scaling of structural units if the sensitivity data is geometry parameter sensitivity, and performing a topology reconstruction operation of topology growth, node splitting, topology degradation, or pruning if the sensitivity data is topology presence sensitivity.
6. The method of claim 1, wherein updating the physical field distribution and sensitivity data in the first-order neighborhood of the operation object of the optimization task, maintaining the target index in synchronization increments until a preset convergence condition is satisfied, and obtaining a lattice topology skeleton, includes: adopting a local interpolation method or a structure-based method to rapidly determine the topology or geometrically changed physical field distribution in the first-order neighborhood of the operation object, and synchronously updating the sensitivity data of nodes and structural units in the region; Performing incremental maintenance on the target index, wherein when the space layer is updated, the leaf node index of the node is calculated through Morton codes, and only corresponding key value pairs are updated; if the updated sensitivity data meets the preset threshold condition, regenerating an optimization task by a corresponding node or a structural unit, and adding the optimization task into the priority queue; and circularly executing the steps of determining physical field distribution, updating sensitivity data, incrementally maintaining the target index and generating an optimization task until a preset convergence condition is met, and ending iteration to obtain a lattice topological skeleton, wherein the preset convergence condition comprises an effective task that the volume of the residual material reaches a target volume fraction, the global maximum stress is lower than allowable stress or the sensitivity of a priority queue is not higher than an operation threshold.
7. The method of claim 1, wherein performing geometric entity reconstruction, topology validity verification, and additive manufacturing process constraint verification on the lattice topology framework comprises: Extracting endpoint coordinates and section radius information of all structural units in the lattice topological skeleton, and constructing a full-field scalar function by adopting a weighted symbol distance field technology; generating a smooth transition curved surface through an exponential or polynomial mixing function aiming at a node area where the multiple structural units meet; Setting a zero isosurface threshold value, and discretizing the scalar function into a closed triangular grid by adopting a moving cube algorithm or a double-contour algorithm so as to complete geometrical entity reconstruction; performing manifold inspection on the closed triangular meshes, checking the water tightness of the model, and automatically eliminating non-manifold edges, holes and self-intersecting patches; Detecting a region with a hanging angle larger than a preset angle threshold value or a wall thickness smaller than a preset thickness threshold value in the model based on preset additive manufacturing process parameters, and automatically correcting by a Laplace smoothing or local grid subdivision algorithm; And packaging the corrected model into a standard additive manufacturing file, and generating a lattice metadata text report containing a node connectivity list and a structural unit radius distribution list, wherein the standard additive manufacturing file is in the format of STL, OBJ or 3MF.
8. A topology optimization system of a lattice structure, comprising: The system comprises an index construction module, a target index generation module, a target optimization module and a target optimization module, wherein the index construction module is used for establishing a target index according to an initial design domain or an initial lattice model of a target to be optimized, the target index comprises a topology layer, a space layer and a mapping table, the topology layer is used for representing the connection relation between nodes in the target to be optimized and a structural unit, and the space layer is used for representing the space position information of the nodes in the target to be optimized; The sensitivity analysis module is used for executing multi-physical-field sensitivity analysis on the target to be optimized according to a preset boundary condition based on the target index, acquiring full-field physical response data and converting the full-field physical response data into sensitivity data, wherein the sensitivity data comprises geometrical parameter sensitivity and topology existence sensitivity; The topology evolution module is used for generating a priority queue according to the absolute value of the sensitivity data, the priority queue comprises a plurality of optimization tasks which are arranged in sequence, and performing topology reconstruction and geometry optimization operations on the target to be optimized according to the sequence of the queue to obtain a lattice structure intermediate model; The local optimization module is used for updating physical field distribution and sensitivity data in a first-order neighborhood of an operation object of the optimization task aiming at the lattice structure intermediate model after each optimization task is completed, and synchronously maintaining the target index in an incremental mode until a preset convergence condition is met, so as to obtain a lattice topology framework; And the result output module is used for carrying out geometric entity reconstruction, topology effectiveness verification and additive manufacturing process constraint verification on the lattice topology framework and outputting a standard additive manufacturing file and lattice metadata text report corresponding to the target to be optimized.
9. An electronic device, comprising: A memory for storing instructions executable by the processor; wherein the processor is configured to execute the instructions to implement a topology optimization method of the lattice structure of any one of claims 1-7.
10. A computer readable storage medium, wherein at least one computer program is stored in the computer readable storage medium, and the at least one computer program is loaded and executed by a processor, so that the computer implements the topology optimization method of the lattice structure according to any one of claims 1-7.

Description

Topology optimization method, system, equipment and storage medium of lattice structure Technical Field The present invention relates to the field of topology optimization technologies, and in particular, to a topology optimization method, system, device, and storage medium for a lattice structure. Background With the continuous progress of additive manufacturing technology, the lattice structure has been widely applied in high-end fields such as aerospace, automobile engineering, biomedical and the like by virtue of the outstanding advantages of light weight, high strength, excellent heat dissipation, good biocompatibility and the like. However, in a complex service scenario, a single uniform lattice structure is difficult to meet performance requirements under the limitation of multiple physical fields and multiple constraints, so that accurate distribution of materials and extremely improved structural performance are required to be achieved through topology optimization, and how to consider design freedom and calculation efficiency in the optimization process becomes an important subject to be solved urgently in the current industry. In order to meet the requirement, two typical solutions appear in the prior art, namely, a gradient lattice structure design method based on topological optimization is adopted, the size of a strut of a lattice cell is determined by establishing an initial geometric model, extracting density and stress information of a finite element unit and then utilizing a mapping function relation, and an optimization model is output by combining constraint of an additive manufacturing process, and the other type is a variable density conformal lattice structure design method based on topological optimization, wherein an effective grid area is firstly extracted through variable density topological optimization to generate a two-dimensional or three-dimensional conformal grid, then the size of a rod diameter is optimized based on a function relation between a density gray value and the rod diameter, and finally a conformal lattice structure is generated. However, both of these prior arts have a key disadvantage that topology optimization is inefficient and it is difficult to cope with the optimization requirements of large-scale complex structures. The former technology relies on a global or local search algorithm based on distance, the algorithm complexity is extremely high when processing large-scale lattices of millions of rods, an acceleration data structure is not introduced, the cost rises exponentially when facing multi-physical field coupling calculation, and the weighting mapping algorithm adopted by the latter technology is also insufficient in efficiency, cannot meet the requirement of industry on quick design response, and becomes a core bottleneck for restricting the application of large-scale high-precision lattice structure engineering. Disclosure of Invention The embodiment of the invention provides a topology optimization method, a system, equipment and a storage medium of a lattice structure, which can solve the problems of topology connectivity failure, limited design freedom and low optimization efficiency in the topology optimization of the lattice structure in the prior art, and realize the efficient optimization design of the lattice structure with excellent mechanical/thermal performance and manufacturability in a large-scale complex scene. In order to achieve the above purpose, the embodiment of the present invention adopts the following technical scheme: According to the first aspect, a topology optimization method of a lattice structure is provided, which comprises the steps of establishing a target index according to an initial design domain or an initial lattice model of a target to be optimized, wherein the target index comprises a topology layer, a space layer and a mapping table, the topology layer is used for representing the connection relation between nodes in the target to be optimized and structural units, and the space layer is used for representing the space position information of the nodes in the target to be optimized; the method comprises the steps of establishing a mapping table, establishing a real-time bidirectional index of a topological layer and a space layer, carrying out multi-physical-field sensitivity analysis on the object to be optimized according to a preset boundary condition based on the object index, obtaining full-field physical response data, converting the full-field physical response data into sensitivity data, generating a priority queue according to the absolute value of the sensitivity data, carrying out topological structure reconstruction and geometric form optimization operation on the object to be optimized according to a queue sequence to obtain a lattice structure intermediate model, updating physical field distribution and sensitivity data in a first-order neighborhood of an operation object of the optimization task