Thermal buckling of metal foam sandwich panels for convective thermal protection systems

TLDR: In this article, the response of metal foam sandwich panels (MFSPs) to thermally induced in-plane equibiaxial loading is investigated, and the elastoplastic pre-and postbuckling response of MFSPs is measured and analyzed.

Abstract: Sandwich panels with metal foam cores are studied with application to actively cooled thermal protection systems. To evaluate these panels under thermal loading, a novel experimental technique and load frame, which provide a prominent improvement in the simultaneous preservation of thermal and mechanical boundary conditions during thermomechanical structural testing, are introduced and validated. With this technique, the response of metal foam sandwich panels (MFSPs) to thermally induced in-plane equibiaxial loading is investigated, and the elastoplastic pre- and postbuckling response of MFSPs is measured and analyzed. The in-plane response of the panels is quantified with strain-gauge measurements, and the out-of-plane response across the surface of the panel is captured via shadow moire interferometry. These measurements provide direct visualization and quantification of the initial buckled mode shapes, as well as the evolution of the elastoplastic postbuckled mode shapes from initial buckling into the postbuckling regime. This experimental investigation is the first of its kind, complementing the largely theoretical and numerical body of information on the thermomechanical response of sandwich panels.