Voxel-Based Simulation and Optimization Framework for Thermal Protection System Materials

When a spacecraft enters a planet’s atmosphere at hypersonic speed, its leading surfaces experience intense aerothermal heating. Porous ablative materials, typically composed of a fiber matrix and resin binder, are commonly used as thermal protection systems (TPS) to shield the vehicle. Mesoscale simulations of the coupled thermochemical multiphysics of these materials, analyzed over representative volume elements, provide valuable insights for TPS design. However, high-fidelity three-dimensional simulations using traditional finite element method (FEM) codes are computationally expensive. To address this challenge, we propose an alternative voxel-based framework to rapidly simulate TPS response. This approach employs a matrix-free, multiphysics geometric multigrid solver, which efficiently handles the interactions between physical processes. The framework is verified against the Theoretical Ablative Composite for Open Testing (TACOT) test case 2.1, a widely used benchmark for ablative material modeling. Its performance is compared to Sandia National Laboratories’ Sierra, an established FEM simulation code. Parametric material optimization and uncertainty quantification often require extensive simulation data, making rapid simulation especially essential for these engineering studies. To demonstrate the advantages of our voxel-based framework in this context, we apply it to a current TPS design challenge: optimizing reinforcement fiber geometry to reduce pyrolysis gas pressure.