Comparison of Hex and Tetra Skullcap with a User-Defined Skull Material Model
Abstract
The US Army Combat Capabilities Development Command Army Research Laboratory previously developed a vectorized user-defined material (VUMAT) model in Abaqus/Explicit to capture the failure behavior of human skull bone. Previous publications document the use of the VUMAT to simulate skullcap experiments and the VUMAT conversion from the Abaqus/complete Abaqus environment finite element (FE) solver to the LS-DYNA FE solver. This study further explored the skullcap simulation results by substituting a hexahedral mesh in place of the original tetrahedral mesh to address concerns about tetrahedra-induced noise in the force-time history and stress contours. First, homogeneous meshes were used and the tetra meshes were not subject to locking or excessive noise. Next, the skullcap meshes were compared with the element-specific bone volume fractions. Stresses and forces in these simulations were consistent in the tetrahedral meshes, and somewhat less consistent for the hexahedral meshes due to different contact and hourglass controls in Abaqus and LS-DYNA. Fracture patterns on the posterior skullcap surface in hexahedral meshes were limited by the preexisting mesh lines. These results suggested that the results with the tetrahedral mesh were not subject to unacceptable noise, produce superior fracture patterns, and therefore should be sufficient for future efforts to model skull impacts.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 21, 2024
- Accession Number
- AD1221878
Entities
People
- Caitlin M. Weaver
- Carolyn Hampton
Organizations
- United States Army Research Laboratory