Aerospace Department - EAS Trailblazers Seminar

Abstract

Materials and structures subjected to the extreme conditions of hypersonic flight undergo complex thermochemical degradation and fracture. Understanding and predicting these effects is critical for low-cost, sustainable space access and various scientific, industrial and national security objectives. We elucidate the fundamental mechanisms governing both ceramic and ablative thermal protection systems using a theoretical formulation and large-scale simulation framework for fracturing solids with complex post-fracture thermochemical response. First, a computational model of recently observed thermal shock and pore pressure failures is used to explore key failure modes and potential damage mitigation strategies. Then, a rigorous constitutive theory is shown to capture molecular diffusion through passively oxidizing ultra-high temperature ceramics. Three-dimensional coating simulations expose the channeling mechanisms and a transition from decussating to circumferential cracking that explains the rich variety of surface cracks found in experiments. We corroborate the distinct fracture morphology regimes using a simple structural theory and conclude with exciting avenues for future research.

Biography

Daniel Pickard is a postdoctoral researcher in the Department of Aeronautics and Astronautics at the Massachusetts Institute of Technology. He received undergraduate, masters and doctoral degrees in the same department in 2020, 2022, and 2025. His research is concerned with highfidelity simulation of multiphysics phenomena in solid materials. With his collaborators, he is developing numerical methods to advance our understanding of the physical effects of highenthalpy hypersonic flows on reentry vehicle thermal protection systems. Dr. Pickard enjoys teaching computational mechanics and learning about new developments in related areas.