Development and Validation of a Physics-Based Model for Deployable Hypersonic Decelerator Flexible Thermal Protection Systems

Flexible Thermal Protection Systems (FTPS) have been investigated to support many applications, including thermal protection of inflatable atmospheric entry vehicles. This flexible blanket is composed of a stack of multiple material sheets, including heat rate resistant outer fabrics, heat load resistant insulation, and an air-tight gas barrier to prevent pressure leaks. My dissertation presents three contributions to the field of aerospace engineering to assist with thermal modeling, material testing, and design of FTPS. A conceptual, 1-D thermal response model predicts in-depth temperatures of FTPS layups during arc-jet ground testing. An extended inverse estimation methodology is developed and applied to the thermal model borrowing concepts from inverse heat transfer analysis, parameter estimation, and probabilistic analysis. In this methodology, an algorithm intelligently adjusts thermal response model input parameters to help minimize error between temperature predictions and measurements to assist with model verification and validation. Some FTPS insulators experience decomposition under extreme heating conditions, while others do not. To further characterize fibrous insulators that undergo decomposition, a thermogravimetric analysis (TGA) testing campaign was performed to obtain the associated activation energy for thermal response modeling. A new material testing methodology was developed to obtain the approximated distribution of activation energy from a set of repeated TGA experiments. This contribution will calculate the mean, uncertainty, and distribution of activation energy for multiple fibrous insulators. The final contribution presents a novel, simulation-based FTPS design methodology to obtain a final FTPS insulator configuration efficiently with limited resources. The complete design process uses inputs such as a candidate insulator pool, insulator material properties, and a nominal mission profile. Using the methods mentioned above, candidate insulators are designed efficiently, providing FTPS insulator stackup configurations that satisfy mission requirements.