Thermal-structural post-bucking and limit-cycle oscillation of Functionally Graded Materials

Thermal post-buckling and limit-cycle oscillation characteristics of Functionally Graded Material (FGM) structures are investigated based on the neutral surface concept. In particular, the material properties are non-homogeneous and vary gradually from one surface to the other. Furthermore, the properties are to be considered as temperature-dependent characteristics, and the neutral surface concept is adopted instead of the mid-plane to consider the reference plane due to the asymmetric properties in the thickness direction of model. In the formulation, the First-order Shear Deformation Theory (FSDT) of plate is used, and the geometric nonlinearity is accounted for by the von Karman strain-displacement relations. Also, steady state thermal conduction effects are assumed as a one dimensional heat transfer on the surface of the structure. For the numerical analysis, the Newton-Raphson method is applied to solve the thermal post-buckling behavior, while Newmark's time integration method is employed to resolve the limit-cycle oscillation. In order to validate the analysis results, the results of this paper based on the neutral surface are compared with the data from previous papers using the conventional approach for FGMs model. Finally, effects of the neutral surface on the non-linear thermo-mechanic behavior of structure are discussed in detail.