Research On GBESO Topology Optimization And Reconstruction Of Mechanical Structure Based On CAD/CAE Rapid Response

Conceptual design,basic design and detailed design are three stage of the process ofmechanical structure design. Each of them contains the circulation of de-sign-optimize-redesign. With the continuous development of CAD and CAE technology,efficiency and quality of the mechanical structure design have a large increase.However,due to increasing competition in product markets,the requirements of mechanicalproduct design are constantly improved and the design of high efficiency,high precision andlow-cost design become the goal of the designers. Therefore,the key of mechanical productdesign is to achieve a low-cost and high-quality design in a short term.On the basis of the existing research on the mechanical structure design method in thispaper,the conversion method between CAD and CAE finite element model based on meshdata was studied,Bi-directional relevance model transformation mechanism based on thetheory of parametric design and shared data was established,mathematical model of themechanical structure topology optimization with BESO (Bi-directional EvolutionaryStructural Optimization) was deduced,the GBESO (Genetic Bi-directional EvolutionaryStructural Optimization) optimization strategy based on elitist preservation was putforward,reverse-engineered reconstruction method of optimized outcome model based onthe characteristics and constraints was set,and the theoretical guidance and method toachieve the high efficiency,high precision and low-cost mechanical structure design wereprovided. The specific content as follows:(1) Researching on the theory of parametric design, parametric CAD modeling principleswas built based on characteristics by the analysis of mechanical structure design process.Implementation method of data transmission was discussed and sharing mechanism of CADmodel and its associated data was established. By analyzing the transformation mechanism of CAD model to CAE model, conversion method of finite element model was found andBi-directional relevance model transformation mechanism was established. Fast and accurateCAD/CAE response in structural design process was achieved and the foundation forsubsequent optimization was laid.(2) By analyzing the optimization concept of evolutionary structural topologyoptimization, mathematical model of mechanical structure topology optimization with BSEOin lightweight design, stress optimized design and stiffness maximize design deduced. For theproblems that slower optimum speed of BESO under the influence of its optimization criteriaand optimal results were not necessarily the truly optimal solution of original structure. Byintroducing elitism strategy of GA, the optimize method and the solution on key issues ofGBESO were obtained. Through the comparison to optimal results with existing topologyoptimization methods, the stability and efficiency of the optimize method were verified.(3) By analyzing ubiquitous numerical problems in topology optimization based on thefinite element method such as checkerboard phenomenon and serrated border, introducingreverse engineering technology, extracting topology optimization results data in projectdatabase, and based on point-cloud data in material removal area, numerical processingmethods for design and manufacture were proposed.Feature Fitting was achieved with the technology of feature extraction and constraintrecognition. CAD model in material removal area was built for boolean subtraction withsource model. The automatic reconstruction of the geometric model with topologyoptimization results was achieved. Taking groove division as an example to verify thefeasibility of the method,the problems that huge data,much time consuming and uncertainprecision in hand-drawn CAD model of topology optimization results were solved,methodsbasis in fast optimal design of mechanical structures were provided.(4) Based on the structural topology optimization theory and methods of CAD/CAErapid response,3-D model parametric design of magazine structure was achieved. Accordingto the topology optimization results of the components and the assembly requirements ofmagazine, quick update of the parametric model of optimized magazine structure was realized.By calling the database file, magazine mechanical properties before and after optimizationwere comparative analyzed. Under the condition that meeting the design requirement ofstiffness and strength, optimized model has a17.9%reduction in quality. The results showthat this method applied to optimal design of continuum has a great significance on improving design scheme, reducing structural weight and realizing lightweight design.