Frictionally-excited thermoelastic instability in functionally graded material

A transient finite element simulation is developed for the two-dimensional thermoelastic contact problem considering a stationary functionally graded material (FGM) between sliding layers, to investigate thermoelastic instability (TEI) due to frictional heating at the interface. The result shows that the critical speed of the FGM coating disk is larger than that of the conventional steel disk. The effect of the nonhomogeneity parameter in FGM is also investigated and it is implied that there is an optimal nonhomogeneity parameter which gives a maximum critical speed within a specific coating layer thickness. It is concluded that FGMs restrain the growth of perturbation and delay the contact separation.