Thermoelastic instability of a functionally graded layer interacting with a homogeneous layer

• Gradient index has great effect on critical heat flux for Types 1, 2 and 3 combinations.
• System with the thinner FGM layer is more stable than that with the thicker layer.
• Critical heat flux increases significantly with the increase of thermal contact resistance.

The interaction between the thermoelastic distortion and pressure-dependent thermal contact resistance can cause the themoelastic instability when the conductive heat transfers between two elastic bodies in the static frictionless contact. Using the perturbation method, this paper investigates the thermoelastic instability of a system consisting of a functionally graded material (FGM) layer and a homogeneous layer under the plane strain state. The two layers are pressed together by a uniform pressure, and transmit a uniform heat flux at their interface. The material properties of the FGM layer are assumed to be of exponential variation along the thickness direction. The thermoelastic stability behavior of five types of material combinations depending on the ratio of their material properties are discussed in details. The results imply that the FGMs can be used to improve the thermoelastic contact stability of the systems.