Studies on Fluid-Thermal-Structural Coupling for Aerothermoelasticity in Hypersonic Flow

The field of aerothermoelasticity plays an important role in the analysis and optimization of airbreathing hypersonic vehicles, impacting the design of the aerodynamic, structural, control, and propulsion systems at both the component and multidisciplinary levels. This study aims to expand the fundamental understanding of hypersonic aerothermoelasticity by performing systematic investigations into fluid thermal structural coupling. A focus is on the targeted use of simplified coupling procedures in order to abate the computational effort associated with comprehensive aerothermoelastic analysis. Because of the fundamental nature of this work, the analysis is limited to cylindrical bending of a simply supported, von Karman panel. Multiple important effects are included in the analysis: namely, 1) mutual coupling between elastic deformation and aerodynamic heating, 2) transient arbitrary in-plane and through-thickness temperature distributions, and 3) the associated thermal stresses and material property degradations. It is found that including elastic deformations in the aerodynamic heating computations results in nonuniform heat flux, which produces nonuniform temperature distributions and material property degradations. This results in localized regions in which material temperature limits may be exceeded; it also impacts flutter boundary predictions and nonlinear flutter response. Additionally, the tradeoff between computational cost and accuracy is evaluated for aerothermoelastic analysis based on either quasi-static or time-averaged dynamic coupling. It is determined that these approaches offer substantial reductions in computational expense, with negligible loss of accuracy, for aerothermoelastic analysis over long-duration hypersonic trajectories.