基于空间微四面体的异质材料零件建模方法

当前以均质材料为设计前提的大多数商用计算机辅助设计系统难以描述异质材料零件(Heterogeneous objects,HEO)的结构信息和材料信息,已有的HEO建模方法也基本上都缺少与通用的建模软件系统及快速成形设备的兼容性。基于此,以几何与材料信息基本映射关系为基础,提出一种基于常用数据格式——表面三角化数据(Stereo lithography,STL)以构建微四面体空间单元的HEO建模方法。通过建立实体、微四面体、STL面片、空间节点四者之间的对应关系,进行HEO实体模型的逐层分解,从而形成被离散化的微四面体空间单元网格节点,并赋予网格节点相应的材料信息,再根据单元网格节点的三维位置及材料值逐一计算各微四面体表面处的结构和材料分布,进而实现整个HEO边界曲面至内部的结构及材料设计,利用实例验证了该方法在复杂HEO设计方面的有效性。

Micro-tetrahedral-based Representation for Heterogeneous Objects Modeling

Most of the commercial CAD systems are fail to represent heterogeneous objects(HEO) since they are based on the premise that the objects under design are homogeneous in material composition,and the majority of existing approaches lack compatibility with traditional CAD software packages and rapid prototyping systems.An HEO modeling is approached,which employs tetrahedral solid cell and common stereo lithography data(STL) based on mapping relationship between HEO geometry and its materials.HEO is decomposed hierarchically as the sequence of solid,tetrahedral cells,STL facets and voxels.Each voxel of tetrahedral cell is defined by its space coordinate,facets vectors and material information.Furthermore,HEO exterior and interior geometry and material distributions are described.A systematic design and built process of HEO prototype is demonstrated as a case study.Results show that the proposed approach can facilitate the design of complex heterogeneous objects.