A Transfinite Meshing Approach for Body-In-White Analyses

Summary

A Transfinite Meshing Approach for Body-In-White Analyses Kirk Beatty and Nilanjan Mukherjee Meshing and Abstraction Group Digital Simulation Solutions Siemens PLM Software 2000 Eastman Dr., Milford, Ohio 45150 USA kirk.beatty@siemens.com, mukherjee.nilanjan@siemens.com Summary. A very wide range of finite element analyses required to design car-bodies calls for quadrilateral meshes with austere quality needs. Quadrilaterals being varying strain and non-planar, element quality, in body-inwhite analyses, is virtually impossible to measure with a single parameter. Auto-designers mostly prefer heuristic element quality metrices that catapult the need for predominantly orthogonal meshes. Transfinite or “mapped” meshing thus assumes great importance. The present investigation presents a holistic transfinite meshing approach for body-in-white analyses involving groups of tessellated faces. A new corner detection algorithm is proposed. The concept of “pseudo-edges” is introduced to cluster face edges into four logical sides. “pseudo-edge-clans” are next formed for the purpose of count propagation that does not require traditional LP solves. In the meshing process, we use 2D domain generation from a 3D tessellation at two steps. During corner determination we use a least squares conformal map with free boundaries to find boundary angles in 2D. After pseudo edges are identified, 2D domain for meshing a face is generated using a constrained rectangular boundary. In this second use of our domain generation method, we make use of a mapping type parameter which varies from conformal (angle preserving) solution to an authalic (area preserving) map. Based on practical examples, the best value for the mapping type parameter for the second domain generation step was found to be about 0.7. We present several results to illustrate our process of meshing for body-in-white analyses.