Verification Studies on Hypersonic Structure Thermal/Acoustic Response and Life Prediction Methods

Boeing and United States Air Force Research Lab (AFRL) have conducted a research program to study current production structural analysis methods for use in hypersonic vehicle design and analysis. The focus was to identify, verify and quantify knowledge gaps in understandings of design environment, high temperature material behavior, and analysis approach in the prediction of structural response and life of hypersonic structures. Phase I of the program identified these knowledge gaps by performing thermal and stress analyses and sizing on a hypersonic reference vehicle with design loads and thermal environment from a representative flight trajectory. In Phase II, the knowledge gaps were verified through detailed sizing and analysis of four vehicle surface panels. This paper focuses on the knowledge gaps associated with the panel dynamic response to thermal-acoustic loads. This knowledge gaps identified in Phase I were verified through detailed finite element analyses of a panel using both linear frequency response and nonlinear transient dynamic analysis. The study included a temperature field for loads and material properties. The acoustic loading was defined from a typical acoustic spectrum for Turbulent Boundary layer excitation. The dynamic analysis related knowledge gaps were discussed and comparisons of linear and nonlinear analysis results were made.