Mechanical model for the interfacial thermal stress in porous ceramic foam coatings bonded to a substrate

Coatings of porous ceramic foams have potential applications in thermal protection systems of space shuttles. This paper develops a mechanics model for evaluation of thermal stress of porous ceramic foam coating/substrate structures under thermal shock temperature variation. Numerical results show that interfacial stresses exhibit singularity at the edge of ceramic foam coating. Stress intensity factor will reduce when ceramic foam coating has a larger density or a larger thermal conductivity. Comparison between beam model and membrane model is made and it suggests that consideration of bending stiffness is essential for correct evaluation of the thermal stress in the ceramic foams.