Decomposing complex thin-walled CAD models for hexahedral-dominant meshing

Abstract

This paper describes an automatic method for identifying thin-sheet regions (regions with large lateral dimensions relative to the thickness) for complex thin-walled components, with a view to using this information to guide the hexahedral (hex) meshing process. This fully automated method has been implemented in a commercial CAD system (Siemens NX) and is based on the interrogation and manipulation of face pairs, which are sets of opposing faces bounding potential thin-sheet regions. Careful consideration is given to the mapping, merging and intersection of face pairs to generate topologies suitable for sweep meshing the thin-sheet regions, and for treating the junctions between adjacent thin-sheet regions. It is proposed that hex meshes be applied to thin-sheet regions by quad meshing one of the faces bounding the thin-sheet region and sweeping it through the thickness to create hex elements. Decisions on the generation and positioning of the cutting surfaces required to isolate thin-sheet regions are made by considering the likely impact on the quality of the resulting mesh. The method delivers a substantial step towards automatic hex meshing for complex thin-walled geometries. A significant reduction of the degrees of freedom (DOF) can be achieved by applying anisotropic hex elements to the identified thin-sheet regions.

Capturing simulation intent in an ontology: CAD and CAE integration application

“…As described in Section 2, a segmentation of CAD components might be required to apply a particular meshing strategy over regions of interest. In this paper, we show the capability to store embedded partitions of component cells by segmenting thin walled CAD models for hex-dominant meshing using the tools of Sun et al (L. Sun et al 2017a, 2017b. The tool subdivides a B-Rep solid model into regions producing appropriate sub-solids for hex-meshing or dimensional reduction operations.…”

“…cavities, air passage, clearance seals etc. Similarly to the work of Sun et al (L. Sun et al 2017a, 2017b on structural components, a morphology analysis of a fluid domain is required for a better integration of multi-physics models. Currently, the proposed framework is compatible with the ontology developed by (Vilmart, Léon, and Ulliana 2018).…”

A Quaternion-Based Piecewise 3D Modeling Method for Indoor Path Networks

“…Generating 3D models from lines automatically is a common task in graphical modeling and computer-aided design, e.g., in generation of pipelines [9,10] and machine parts [11][12][13]. There are many ways of calculating the coordinates of model vertices in 3D model generation, such as Euler angle methods and quaternion methods.…”