CN117574470B

CN117574470B - Intelligent model reconstruction method and device for industrial structure

Info

Publication number: CN117574470B
Application number: CN202311607652.7A
Authority: CN
Inventors: 任宏塬; 杜建镔; 夏博; 陈雪乾; 张海西; 周平章
Original assignee: Beijing Youjie Future Technology Co ltd; Tsinghua University
Current assignee: Beijing Youjie Future Technology Co ltd; Tsinghua University
Priority date: 2023-11-28
Filing date: 2023-11-28
Publication date: 2024-08-23
Anticipated expiration: 2043-11-28
Also published as: CN117574470A

Abstract

The application provides an intelligent model reconstruction method of an industrial structure, which comprises the following steps: generating a triangular grid model based on the structure optimization result; re-gridding the triangular grid model to obtain a quadrilateral grid model; performing model partitioning and topology inspection on the quadrilateral mesh model to obtain a patch layout result; carrying out harmonic mapping and uniform sampling on the quadrilateral mesh model based on the patch layout result to obtain sampling points; and (3) taking the sampling points as fitting points to carry out NURBS surface fitting to obtain CAD model files corresponding to the topological optimization structure. The application adopting the scheme realizes the full-flow engineering optimization design.

Description

Intelligent model reconstruction method and device for industrial structure

Technical Field

The application relates to the technical field, in particular to an intelligent model reconstruction method and device for an industrial structure.

Background

The structure optimization method is widely applied to the industrial fields of aerospace, automobiles, machine tools, buildings, instruments and the like, takes up important roles in research and development design, and the industrial structure obtained by the structure optimization has wide application range and great development potential. At present, the development of the design and manufacturing industry is rapid, the development and production requirements of various products cannot be met due to a large number of manual traditional industrial design flows, and designers continuously pursue shorter development periods, lower production cost, better product performance, more convenient design modes and higher product quality. In the industrial structure optimization design, compared with size optimization and shape optimization, the topology optimization has larger design freedom degree, and can bring about brand new innovation of industrial design. However, the result obtained by the variable density method can generate zigzag boundaries and gray cells, and cannot be directly used for subsequent parameterization design and manufacture. The result obtained by the level set method is an implicit boundary and lacks explicit expression. The structural optimization results often contain some details that are difficult to handle in conventional manufacturing, resulting in high manufacturing costs and even failure to manufacture, which may reduce the mechanical properties of the structure if blind structural modifications are made. The traditional CAD reconstruction of the model result is carried out through the manual post-processing, and the process is complex and long in time period.

Disclosure of Invention

The present application aims to solve at least one of the technical problems in the related art to some extent.

Therefore, the first object of the present application is to provide an intelligent model reconstruction method for an industrial structure, which solves the technical problems of complicated process and long time period of the existing method, and realizes the full-flow engineering optimization design of the industrial structure.

A second object of the present application is to propose an intelligent model reconstruction device for industrial structures.

To achieve the above object, an embodiment of a first aspect of the present application provides an intelligent model reconstruction method for an industrial structure, including: generating a triangular grid model based on the structure optimization result; re-gridding the triangular grid model to obtain a quadrilateral grid model; performing model partitioning and topology inspection on the quadrilateral mesh model to obtain a patch layout result; carrying out harmonic mapping and uniform sampling on the quadrilateral mesh model based on the patch layout result to obtain sampling points; and (3) taking the sampling points as fitting points to carry out NURBS surface fitting to obtain CAD model files corresponding to the topological optimization structure.

According to the intelligent model reconstruction method of the industrial structure, provided by the embodiment of the application, the structural optimization result is automatically and intelligently reconstructed into the CAD model based on Rosy field solving, quadrilateral layout dividing and spline fitting of the grid model, so that seamless connection between the topology optimization and other methods and CAD is realized. The method has an important pushing effect on the realization of the integrated design and production manufacturing of the industrial structure, thereby realizing the full-flow engineering optimization design of 'application scene-structure optimization result-quadrilateral layout-NURBS curved surface-CAD model-shape optimization/parameter detailed design-production manufacturing'.

Optionally, in one embodiment of the present application, the generating process of the structure optimization result includes:

setting application scenes and boundary conditions of industrial products;

Modeling and topology optimization solving are carried out based on the set content, and a pseudo-density field/level set function field is obtained as a topology optimization result.

Optionally, in an embodiment of the present application, performing model partitioning and topology checking on the quadrilateral mesh model to obtain a patch layout result, including:

obtaining the layout of a plurality of quadrilateral patches of a quadrilateral mesh model, wherein each quadrilateral patch is a single-communication curved surface with a boundary, and the topology is isomorphic to a disc;

And checking the topological correctness of all quadrilateral patches, and secondarily dividing the patch layout with the deficiency of not 0 by adding coincident points or coincident edges to obtain a patch layout result.

Optionally, in an embodiment of the present application, performing harmonic mapping and uniform sampling on the quadrilateral mesh model based on the patch layout result to obtain sampling points includes:

Blending and mapping the quadrilateral mesh model to a planar parameter domain;

and uniformly sampling in the plane parameter domain to obtain sampling points and corresponding space coordinate information.

Optionally, in an embodiment of the present application, performing NURBS surface fitting with the sampling points as fitting points to obtain a CAD model file corresponding to the topology optimization structure, including:

And carrying out NURBS surface fitting according to a preset surface order and a fitting mode based on fitting points to obtain a CAD model file corresponding to the topological optimization structure expressed by NURBS, wherein the preset fitting mode is interpolation fitting or least square approximate fitting.

To achieve the above object, an embodiment of a second aspect of the present invention provides an intelligent model reconstruction device for an industrial structure, which includes a model generating module, a model updating module, a model partitioning module, a sampling module, and a fitting module, wherein,

The model generation module is used for generating a triangular grid model based on the structure optimization result;

the model updating module is used for re-gridding the triangular grid model to obtain a quadrilateral grid model;

The model partitioning module is used for performing model partitioning and topology inspection on the quadrilateral mesh model to obtain a patch layout result;

the sampling module is used for carrying out harmonic mapping and uniform sampling on the quadrilateral mesh model based on the patch layout result to obtain sampling points;

And the fitting module is used for carrying out NURBS surface fitting by taking the sampling points as fitting points to obtain CAD model files corresponding to the topological optimization structure.

Optionally, in an embodiment of the present application, the apparatus further includes a structure generating module, specifically configured to:

setting application scenes and boundary conditions of industrial products;

modeling and topology optimization solving are carried out based on the set content, and a pseudo density field/level set function field is obtained as a structure optimization result.

Optionally, in one embodiment of the present application, the model partitioning module is specifically configured to:

Optionally, in one embodiment of the present application, the sampling module is specifically configured to:

Blending and mapping the quadrilateral mesh model to a planar parameter domain;

Optionally, in one embodiment of the present application, the fitting module is specifically configured to:

Additional aspects and advantages of the application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the application.

Drawings

The foregoing and/or additional aspects and advantages of the application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic flow chart of an intelligent model reconstruction method for an industrial structure according to an embodiment of the application;

FIG. 2 is a flow chart of model reconstruction according to an embodiment of the present application;

FIG. 3 is an exemplary diagram of a topology optimized derived cantilever Liang Qingliang chemical design result in accordance with an embodiment of the present application;

FIG. 4 is an exemplary diagram of a quadrilateral mesh model obtained by re-meshing in accordance with an embodiment of the present application;

FIG. 5 is a diagram illustrating a secondary division of a patch layout with a deficiency of not 0 by adding overlapping points or overlapping edges according to an embodiment of the present application;

FIG. 6 is a NURBS patch line block diagram in a reconstructed CAD model of topology optimization results according to an embodiment of the present application;

FIG. 7 is an exemplary diagram of a reconstructed CAD model of another cantilever Liang Qingliang-based design result under different application conditions according to an embodiment of the present application;

Fig. 8 is a schematic structural diagram of an intelligent model reconstruction device for an industrial structure according to an embodiment of the present application.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present application and should not be construed as limiting the application.

Aiming at the problem that the results obtained by structural optimization such as industrial lightweight design are difficult to apply, based on Rosy field solving and spline fitting on the surface patches, a Non-uniform rational B spline (Non-Uniform Rational B-Splines, NURBS) curved surface and a reconstructed CAD model corresponding to the design results are obtained. Although the prior art provides a smoothing post-processing function for the structure optimization result, a large number of triangular patches are usually adopted to fit the structure boundary, the variable scale is large, so that further detailed parameterization design and model adjustment are difficult to effectively perform, and the smoothing effect is often poor, so that the manufacturing is not facilitated. According to the invention, the model boundary with the complex topology is split into a plurality of quadrilateral surface patch layouts with the topology isomorphic to the disc, so that various complex structural components can be processed, and meanwhile, the intelligent degree and the automation degree are higher.

The following describes an intelligent model reconstruction method and device for an industrial structure according to an embodiment of the present application with reference to the accompanying drawings.

Fig. 1 is a schematic flow chart of an intelligent model reconstruction method for an industrial structure according to an embodiment of the application.

As shown in fig. 1, the intelligent model reconstruction method of the industrial structure comprises the following steps:

step 101, generating a triangular grid model based on a structure optimization result;

102, re-gridding the triangular grid model to obtain a quadrilateral grid model;

step 103, performing model partitioning and topology inspection on the quadrilateral mesh model to obtain a patch layout result;

104, carrying out harmonic mapping and uniform sampling on the quadrilateral mesh model based on the patch layout result to obtain sampling points;

And 105, carrying out NURBS surface fitting by taking the sampling points as fitting points to obtain CAD model files corresponding to the topological optimization structures.

setting application scenes and boundary conditions of industrial products;

Blending and mapping the quadrilateral mesh model to a planar parameter domain;

The method for reconstructing an intelligent model of an industrial structure according to the present application will be described in detail by way of specific examples.

In this embodiment, a mesh model composed of a large number of triangle patches is derived according to the calculation result of the structure optimization, and common formats include STL, PLY, OBJ and OFF. Since NURBS surface basis functions have two parameter directions, a network of quadrilateral elements needs to be laid on the triangular mesh prior to NURBS surface fitting, a step called re-meshing. In order to obtain a NURBS patch with better performance, harmonic mapping and uniform sampling on a quadrilateral patch are required, and sampling points are used as fitting points. The harmonic mapping is the harmonic energy minimization mapping between two manifolds, and has the advantages of ensuring the minimum deformation generated in the mapping process, having the corner protection property and the rounding protection property, and further obtaining uniform and high-quality grids, adjustable and controllable grid shapes and density degrees and the like. The curved surface subjected to the harmonic mapping treatment is a single-connected curved surface with a boundary and is topologically isomorphic with a disk. Fig. 2 is a model reconstruction flow chart, as shown in fig. 2, the CAD model reconstruction flow chart is:

deriving a triangular mesh model from the topology optimization results, as shown in FIG. 3, an exemplary graph of the design results for cantilever Liang Qingliang derived for topology optimization;

Converting the triangle mesh model into a quadrilateral patch mesh, namely re-meshing, as shown in fig. 4, and performing example diagram of the quadrilateral mesh model obtained by re-meshing;

Obtaining a plurality of rough quadrilateral surface patch layouts of the structural surface, namely performing model partitioning, so that each surface patch is a single communicated curved surface with a boundary, and the topology is isomorphic to a disc;

Checking the topological correctness of all the patches, and secondarily dividing the patch layout with the deficiency of not 0 by adding coincident points or coincident edges, as shown in fig. 5, which is an exemplary diagram of secondarily dividing the patch layout with the deficiency of not 0 by adding coincident points or coincident edges;

Mapping the grid harmony to a plane parameter domain, and uniformly sampling in the parameter domain to obtain the space coordinate information of the fitting point;

According to the preset surface order and fitting mode, NURBS surface fitting is carried out, accurate interpolation fitting or least square approximate fitting can be selected, CAD model files corresponding to the original topological optimization result configuration expressed by NURBS can be obtained, the CAD model files are shown in FIG. 6, NURBS surface patch line diagrams in the reconstructed CAD model of the topological optimization result are shown in FIG. 7, and an exemplary diagram of the reconstructed CAD model of another cantilever Liang Qingliang design result under different application conditions is shown.

In order to realize the embodiment, the application further provides an intelligent model reconstruction device of the industrial structure.

As shown in fig. 8, the intelligent model reconstruction device of the industrial structure comprises a model generation module, a model updating module, a model partitioning module, a sampling module and a fitting module, wherein,

setting application scenes and boundary conditions of industrial products;

Blending and mapping the quadrilateral mesh model to a planar parameter domain;

It should be noted that the foregoing explanation of the embodiment of the method for reconstructing an intelligent model of an industrial structure is also applicable to the device for reconstructing an intelligent model of an industrial structure of the embodiment, and will not be repeated herein.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and additional implementations are included within the scope of the preferred embodiment of the present application in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order from that shown or discussed, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present application.

Logic and/or steps represented in the flowcharts or otherwise described herein, e.g., a ordered listing of executable instructions for implementing logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program is printed, as the program may be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.

It is to be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. As with the other embodiments, if implemented in hardware, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.

Those of ordinary skill in the art will appreciate that all or a portion of the steps carried out in the method of the above-described embodiments may be implemented by a program to instruct related hardware, where the program may be stored in a computer readable storage medium, and where the program, when executed, includes one or a combination of the steps of the method embodiments.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing module, or each unit may exist alone physically, or two or more units may be integrated in one module. The integrated modules may be implemented in hardware or in software functional modules. The integrated modules may also be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product.

The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, or the like. While embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.

Claims

1. An intelligent model reconstruction method of an industrial structure is characterized by comprising the following steps:

generating a triangular grid model based on the structure optimization result;

Re-gridding the triangular grid model to obtain a quadrilateral grid model;

performing model partitioning and topology inspection on the quadrilateral mesh model to obtain a patch layout result;

carrying out harmonic mapping and uniform sampling on the quadrilateral mesh model based on the patch layout result to obtain sampling points;

Carrying out NURBS surface fitting by taking the sampling points as fitting points to obtain CAD model files corresponding to the topological optimization structure;

the generating process of the structure optimization result comprises the following steps:

setting application scenes and boundary conditions of industrial products;

modeling and topology optimization solving are carried out based on the set content, and a pseudo-density field/level set function field is obtained to serve as the structure optimization result;

Performing model partitioning and topology inspection on the quadrilateral mesh model to obtain a patch layout result, wherein the method comprises the following steps:

Obtaining the layout of a plurality of quadrilateral patches of the quadrilateral mesh model, wherein each quadrilateral patch is a single communicated curved surface with a boundary, and the topology is isomorphic to a disc;

Checking the topological correctness of all quadrilateral patches, and secondarily dividing the patch layout with the deficiency of not 0 in a mode of adding coincident points or coincident edges to obtain a patch layout result;

the step of carrying out harmonic mapping and uniform sampling on the quadrilateral mesh model based on the patch layout result to obtain sampling points comprises the following steps:

blending and mapping the quadrilateral mesh model to a planar parameter domain;

2. The method of claim 1, wherein the performing NURBS surface fitting with the sampling points as fitting points to obtain CAD model files corresponding to the topology optimization structure comprises:

And carrying out NURBS surface fitting according to a preset surface order and a fitting mode based on the fitting point to obtain a CAD model file corresponding to the topological optimization structure expressed by NURBS, wherein the preset fitting mode is interpolation fitting or least square approximate fitting.

3. An intelligent model reconstruction device of an industrial structure is characterized by comprising a model generation module, a model updating module, a model partitioning module, a sampling module and a fitting module, wherein,

the fitting module is used for carrying out NURBS surface fitting by taking the sampling points as fitting points to obtain CAD model files corresponding to the topological optimization structure;

the device further comprises a structure generation module, which is specifically used for:

setting application scenes and boundary conditions of industrial products;

The model partitioning module is specifically configured to:

the sampling module is specifically configured to:

blending and mapping the quadrilateral mesh model to a planar parameter domain;

4. The apparatus of claim 3, wherein the fitting module is specifically configured to: