Numerical Simulation of Metallic Thermal Protection System Panel Bowing

Abstract

Numerical simulation of the thermoelastic response of metallic thermal protection panels is presented. The panels, which arebeing designed foruseon the windward surface of theX-33 e ighttest vehicle, deform into convex and concavebowedsurfacesdueto thermalgradientscausedbyaerodynamicheating.Threenumerical models, for the e owe eld, forthein-depth heat transfer, and for the thermoelasticdeformation, are coupled in sequence to yield the transient response of the metallic panel. The aerothermal loads are derived from computational e uid dynamic solutionsandareprescribedasadistributionfunctionwithmaximumbowheightasthegoverningparameter.Finite element models are used to simulate the thermal and structural responses. The coupled simulation is compared to a single-pass uncoupled solution. Results show negligible feedback between the structural deformation and the deformation-induced perturbation of the aerothermal heat load. Nevertheless, signie cant temperature variations on the surface of the panel are produced. The deformations induce lateral temperature gradients that increase the thermal stress within the panel. Finally, it is shown that panel bowing does not appreciably alter the trajectory integrated heat load.