Quality Improvement of Non-manifoldHexahedral Meshes for Critical FeatureDetermination of Microstructure Materials
Qian, Jin, Yongjie Zhang, WenyanWang, Alexis C. Lewis,M.A. Siddiq Qidwai, and Andrew B. Geltmacher
Proceedings, 18th International Meshing Roundtable, Springer-Verlag, pp.211-230, October 25-28 2009
18th International Meshing Roundtable
Salt Lake City, UT, USA.
October 25-28, 2009
1 Department of Mechanical Engineering, Carnegie Mellon University,
5000 Forbes Avenue, Pittsburgh, PA 15213, USA
2 Multifunctional Materials Branch, Naval Research Laboratory,
4555 Overlook Avenue SW, Washington, DC 20375, USA
This paper describes a novel approach to improve the quality of nonmanifold
hexahedral meshes with feature preservation for microstructure materials.
In earlier works, we developed an octree-based isocontouring method to construct
unstructured hexahedral meshes for domains with multiple materials by introducing
the notion of material change edge to identify the interface between two or more materials.
However, quality improvement of non-manifold hexahedral meshes is still
a challenge. In the present algorithm, all the vertices are categorized into seven
groups, and then a comprehensive method based on pillowing, geometric flow and
optimization techniques is developed for mesh quality improvement. The shrink set
in the modified pillowing technique is defined automatically as the boundary of each
material region with the exception of local non-manifolds. In the relaxation-based
smoothing process, non-manifold points are identified and fixed. Planar boundary
curves and interior spatial curves are distinguished, and then regularized using Bspline
interpolation and resampling. Grain boundary surface patches and interior
vertices are improved as well. Finally, the local optimization method eliminates
negative Jacobians of all the vertices. We have applied our algorithms to two beta
titanium datasets, and the constructed meshes are validated via a statistics study.
Finite element analysis of the 92-grain titanium is carried out based on the improved
mesh, and compared with the direct voxel-to-element technique.
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