Mathematical modeling and simulation of porosity on thermomechanical properties of UHTCs under hypersonic conditions

Abstract

Ultrahigh temperature ceramics (UHTCs) were analyzed for their suitability in hypersonic flight conditions using balanced heat equations, transport equation, and finite element modeling technique. Mathematical model was derived on the assumption that the induced porosity follows linear and parabolic solutions of Laplace equation and applied external load mimicking hypersonic conditions with critical heat flux ranging between 7 and 44 MW/m². Simulations were carried out with four different UHTCs combinations and the results outlined a temperature rise exceeding 4700°C with deformation observed on the fixed area and where the heat flux was generated. The influence of porosity had a greater impact on the performance of the material as it led to a reduction in deformation compared to dense samples. Porous UHTCs exhibited a good thermal shock resistance owing to the release of thermal stresses through pores, which also enhanced the thermal insulation of the structure.