improving Metallic Thermal Protection System Hypervelocity Impact Resistance Through Numerical Simulations

摘要

A design of experiments approach has been implemented using computational hypervelocity impact simulations. The purpose of this study is to determine the most effective place to make minor design changes to an existing metallic thermal protection system to improve hypervelocity impact protection provided to underlying components. Simulations are performed using axisymmetric models in a shock-physics hydrodynamics code and compared with existing experimental data. The axisymmetric models are then used in a statistical sensitivity analysis to determine the influence of design parameters on degree of protection. Several damage metrics are identified and evaluated. Damage metrics related to the extent of substructure damage produce misleading results; however, damage metrics related to the degree of dispersion of the hypervelocity projectile produce results that correspond to physical intuition. Based on analysis of variance results, it is concluded that increasing the spacing between the outer surface and the substructure is the most effective way to increase hypervelocity impact resistance. The second most effective design change is to increase the thickness of the outer foil layer. When design considerations are taken into account for the system in this study, it is explained that increasing the thickness of the outer foil layer is the most practical design change.