Multi-view Parameterized Geometry Reconstruction Method For Topology Optimization Results

Structural topology optimization design can assist engineers to design products with better performance and fewer materials.It has important engineering application value in the field of automobile lightweight design.However,there are jagged edges and checkerboard phenomena in the results of topology optimization,which increase the cost and difficulty of subsequent shape optimization and manufacturing.A multiview parametric geometry reconstruction method for topology optimization results is proposed,which can reconstruct the topology optimization results into a parametric model for subsequent processing.The main research contents are as follows:(1)For complex structure model,the model's whole structure cannot be recognized by three views method alone,and the model partition solution based on feature segmentation method is proposed.The complex structure model can be divided into several simple structure models with a certain meaning by using the feature segmentation method based on line skeleton.Some skeletons can be manually modified to obtain satisfactory segmentation structure.(2)For simple structure model,the topology optimization results are transformed into uniform point cloud,and projection direction and projection surface(including three views,local view and specific direction view)are selected.Then,all or part of point cloud is projected by orthographic projection method to get 2D view point cloud,and view boundary is extracted,segmented and reconstructed based on shape geometric template and extended polygon approximation method.And the best 2D reconstructed boundary is determine by selection and evaluation function.The 2D reconstructed boundary is stretched and rotated along the projection direction(including Cartesian coordinates,natural coordinates)to get the entity.Finally,the entity coordinates are transformed into a unified coordinate system and the 3D reconstruction model is obtained by Boolean operation.(3)To improve the accuracy of 2D boundary reconstruction,boundary preprocessing and post-processing are used in the stage of 2D boundary segment reconstruction.Boundary pre-processing includes concave-convex processing,adaptive interpolation and smoothing filtering,which can solve the problem that geometry template cannot handle concave polygon defects,and improve the accuracy and efficiency of 2D boundary processing.Boundary post-processing includes three schemes: arc,direct and chamfer connection,which can be selected flexibly according to the optimization results,thus increasing the adaptability of 3D reconstruction model.(4)The numerical validation of the reconstruction method is carried out by using the classical topology optimization design numerical cases: torsion beam and bridge,and automobile parts: control arm,hub and frame.Under the premise of not significantly increasing the model volume,the reconstructed result can be a simple parametric 3D model,which reduces the difficulty and cost of the topology optimization results' post-processing steps and facilitates the subsequent shape optimization and manufacturing.In this paper,a parameterized geometry reconstruction method of topology optimization results is proposed.The feasibility and effectiveness of the method are verified by classical topology optimization cases and automobile parts,which provides a solution for post-processing of topology optimization results.