Frictionally excited thermoelastic instability in a thin layer of functionally graded material sliding between two half-planes

Frictionally excited thermoelastic instability (TEI) is investigated in the system of a layer of finite thickness which is composed of functionally graded material (FGM), sliding against two homogeneous frictional materials of half-planes at speed V. Results show that ceramic-based FGM, which is composed of ceramic at the sliding interface and steel at the middle of the layer, reduces the susceptibility towards TEI. The effect of nonhomogeneous parameters of FGM on critical speed is investigated for the several combinations of FGM such as steel- or ceramic-based FGM with positive and negative nonhomogeneous parameters, respectively. The material sensitivity to the critical speed for the nonhomogeneous parameter of FGM shows that the nonhomogeneous parameters of the thermal expansion coefficient are strong influential factors in ceramic- or steel-based FGM. The transient evolution of temperature perturbation is also obtained to determine the susceptibility towards hot spotting, showing that the ceramic-based FGM with negative nonhomogeneous parameters has the lowest temperature perturbation amplitude during engagement.