Seminars

We have extended the recently reformulated 10-node composite tetrahedral finite element for solid mechanics. We generalized the gradient operator and mass matrix to curved domains through analytical expressions weighted by subtetrahedra Jacobians. Optimal integration weights were constructed to increase the accuracy of Gaussian quadrature. We preserved the variational structure of the formulation through a new five-field functional with additional, independent fields for the Jacobian and the pressure. A deleterious soft mode, common to both the quadratic and composite tetrahedral element with constant pressure formulations was effectively stabilized through a novel convex energy penalty function that enables the formulation to be viable for shock simulation.
Recent work focused on extending the requisite stabilization scheme to a stressed reference configuration for mesh adaptivity. File-based workflows illustrated new mapping schemes for the stabilization of the energy. Current work focuses on in-core adaptivity with increments in contact resolution and element robustness. We are exploring new approaches for discretizing evolving geometry under large deformations. In addition, we are pursuing the stabilization of inter-element shearing modes for cases in which the shear response is significantly weaker than the bulk response. These new methods will be illustrated for numerous examples including solid torsion and Taylor bar impact.
Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.