采用前期笔者提出的独立覆盖流形法,尝试CAD和CAE融合的新途径。以二维结构的线弹性静力分析为例,实现从CAD到CAE的无缝连接,以及CAE的完全自动化分析。在基于前期CAD几何的流形法研究基础上,给出NURBS曲线(CAD中的通用图形标准)与直线的切割算法,实现CAD几何模型在CAE建模和网格细化中的保形性;通过AutoCAD的DXF图形格式,将CAD中的结构形状、荷载及约束信息直接输出到CAE;基于矩形独立覆盖的自适应分析技术,实现结构静力分析的自动化计算;自动生成有限元网格用于计算结果后处理的图形输出。综合以上研究,用一个二维结构静力分析算例演示了从CAD几何建模和输出,到CAE的自动前处理、自动分析、自动后处理的完整过程,所有的人工操作仅限于CAD中,而CAE分析过程无需人工参与,就可以获得满足设定精度的计算结果。
Abstract
Using Numerical Manifold Method (NMM) based on independent covers proposed in previous study, we attempted a new way of integrating Computer Aided Design (CAD) and Computer Aided Engineering (CAE). Taking 2D static analysis of linear-elastic structures for example, we accomplished the seamless link from CAD to CAE and the total automatic CAE analysis. On the basis of previous study of NMM based on CAD geometry, we put forward algorithms for cutting NURBS (Non-uniform Rational B-spines, regarded as the general graphic standard in CAD) curves with straight lines, hence preserving the shape of geometric model in procedures of CAE modeling and mesh refinement. Meanwhile, data of structural shape, loads and constraints defined in CAD are directly transferred to CAE by means of DXF graphic format of AutoCAD. Furthermore, by using adaptive analysis based on rectangular independent covers, we conducted automatic static analysis of structures and automatic finite elementmeshes for post-processing graphic output of computational results. In association with the above studies, we took a 2D static structure as example to illustrate the entire procedures, including CAD modeling and output, automatic pre-processing, automatic analysis and automatic post-processing in CAE, in which all procedures were automatically accomplished by computer, except for manual operation of CAD model. Finally, we obtained calculated results with given precision.
关键词
CAD和CAE融合 /
数值流形方法 /
独立覆盖 /
自适应分析 /
NURBS /
DXF
Key words
CAD/CAE integration /
Numerical Manifold Method (NMM) /
independent covers /
adaptive analysis /
NURBS /
DXF
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基金
中央级公益性科研院所基本科研业务费项目(CKSF2015033/CL,CKSF2016022/CL)
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