Thomas Voth
Senior Member of Technical Staff

Contact Information:

tevoth@sandia.gov
P. O. Box 5800
Albuquerque, NM 87185-0370
(505) 844-6004
(505) 844-0918 fax

Mesh Enhancement

We are developing and implementing advanced remesh algorithms for Arbitrary Lagrangian Eulerian (ALE) codes. Unlike Lagrangian and Eulerian approaches where the mesh either moves with the material or is fixed in space, respectively, ALE codes allow arbitrary mesh motion. Hence, ALE simulations can take advantage of the strengths inherent in the Lagrangian and Eulerian methods while minimizing their weaknesses. While ALE strategies have been used for some time, the "arbitrariness" of the mesh introduces significant challenges. We are researching several techniques for mesh enhancement using prescriptive target element ideas (through discrete optimization, DO, techniques and Finite Element discretizations of the Laplace Beltrami Equations, FELB). Of current interest is how target elements may be chosen in a way that can provably improve solution quality. Implementation of these ideas into the ALEGRA hydrodynamics code have significantly improved the code's flexibility.

Meso-scale Mechanics

We are developing the FlexFEM eXtended Finite Element (X-FEM) code to model meso-scale mechanics of polycrystalline materials. The X-FEM is a technique which allows inter- and intra-element strong and weak-discontinuities to be introduced into standard Galerkin Finite Element methods. In particular, cracking and material boundaries may be modeled without apriori specification of the respective interface. We are using these techniques to model grain boundary sliding and failure mechanics in micro-machining processes and shock-loading of polycrystalline materials. Of particular interest are the inter- and intra-granular fracture mechanisms. Also of interest are temporal and spatial stability aspects of the X-FEM.

Updated: 7/5/2007

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