FE analysis of crack problems in functionally graded materials under thermal stress

This paper represents a comprehensive study of the fracture behaviour of linear elastic isotropic functionally graded materials (FGMs) subjected to thermal loading. For this purpose, the displacement extrapolation technique (DET) and the displacement correlation technique (DCT) are employed to calculate the thermal stress intensity factor (TSIFs) for inclined cracks located in FGMs, subjected to thermal stresses. Using the Ansys Parametric Design Language (APDL), the continuous variations in the material parameters of the functionally graded medium are treated by specifying the material properties at the centroid of each element. The FE program is investigated to calculate the mixed-mode SIFs under thermal and structural analysis. The FEM results show good agreement with the reference results. The presented FE results obtained by local approach illustrate the influences of the thermal conductivity, the thermal expansion and the crack inclination angle on the mixed mode thermal stress intensity factor and the steady-state temperature distribution around the crack-tips.