Post Refinement Element Shape Improvement for Quadrilateral Meshes

AMD-Vol. 220 Trends in Unstructured Mesh Generation, ASME, pp.9-16, July 1997

MESHING
RESEARCH
CORNER

Ansys, Inc.
275 Technology Drive, Canonsburg, PA 15317
email: matt.staten@ansys.com, scott.canann@ansys.com

presented at
The 1997 Joint ASME/ASCE/SES Summer Meeting
June 29-July 2, 1997
Northwestern University
Evanston Illinois

Abstract
Schneiders and Debye (1995) present two algorithms for quadrilateral mesh refinement. These algorithms refine quadrilateral meshes while maintaining mesh conformity. The first algorithm maintains conformity by introducing triangles. The second algorithm maintains conformity without triangles, but requires a larger degree of refinement. Both algorithms introduce nodes with non-optimal valences. Non-optimal valences create acute and obtuse angles, decreasing element quality.

This paper presents techniques for improving the quality of quadrilateral meshes after Schneiders refinement. Improvement techniques use topology and node valence optimization rather than shape metrics; hence, improvement is computationally inexpensive. Meshes refined and subsequently topologically improved contain no triangles, even though triangles are initially introduced by Schneiders refinement. Triangle elimination is especially important for linear elements since linear triangles perform poorly. In addition, node valences are optimized, improving element quality.

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