Since joining LANL in 1997, Tim has developed and applied large-scale molecular dynamics simulations to the study of dynamic materials behavior, including shock compression and release, sliding friction, and detonation. He also led the development of a novel capability for large-scale agent-based simulations of infectious disease outbreaks, used to guide the design of pandemic influenza mitigation strategies and in response to 2009 H1N1 influenza and 2020-1 COVID-19 pandemics.
He was the founding director of the ASCR Exascale Co-Design Center for Materials in Extreme Environments (ExMatEx) and the Exascale Computing Project (ECP) Co-design center for Particle Applications (CoPA). He is a Fellow of the American Physical Society (APS), past chair of the APS Division of Computational Physics and APS Topical Group on Shock Compression of Condensed Matter, and a member of the DOE Advanced Scientific Computing Advisory Committee. In 2019, he began two new roles within DOE: serving as Chief Operating Officer for the Alliance Strategy Team of the NNSA Predictive Science Academic Alliance Program (PSAAP), and as ECP Co-Design technical lead.