A model of the thermal shock resistance parameter for functionally gradient ceramics

The thermo-elastic response of functionally gradient ceramics is investigated by means of the calculations of unsteady temperature fields and unsteady thermal stresses for an infinite functionally gradient ceramic plate with symmetrical structure under the convective boundary condition. A new strength-based fracture criterion for thermal shock of functionally gradient materials (FGM) ceramic plate is put foreword and consequently a new expression of critical temperature difference ΔTc, leading to the local fracture strength at the surface as the thermal shock resistance parameter for infinite FGM ceramic plate with symmetrical structure is obtained. The effects of the distributions for thermo-physical properties on the thermal shock resistance of the functionally gradient ceramics are analyzed via numerical calculations in contrast to homogeneous ceramics, from which some suggestions on design of functionally gradient ceramics with high thermal shock resistance are made.