A Discontinuous-Galerkin, Lagrangian Thermo-chemo-mechanical Material Response Solver for the Analysis of Ablative Thermal Protection Systems

In this work we present a computational framework for modeling thermo-chemo-mechanical material response in aerospace structures exposed to thermal and chemical ablation. Our approach is based on a Lagrangian description of the solid mechanics response that incorporates phenomenological models of chemical reactions within a porous material. We adopt a discontinuous Galerkin (DG) finite element discretization of the governing solid mechanics, heat transfer, and chemical reaction and transport equations. As previously established, the DG framework provides some significant numerical advantages in the modeling of advection-dominated problems, as well as in the presence of material and structural fracture and failure. In addition, a mesh recession algorithm is utilized to account explicitly changes in geometry in time due to material ablation. Numerical examples are presented to demonstrate the basic capabilities of the computational framework and to illustrate its ability to model thermo-chemically induced deformation, stresses and surface recession in pyrolyzing thermal protection materials in use in vehicles during atmospheric reentry.