Thermal shock resistance of functionally graded materials

Abstract

Transient temperature field and associated thermal stresses in functionally graded materials (FGMs) are determined by a finite element/finite difference (FE/FD) method. Temperature-dependent material properties are taken into consideration. Explicit expressions for one-dimensional transient thermal conduction in some common elements, such as plate, shell and sphere, are given. These expressions are useful for material engineers and scientists to determine the thermal stresses and strength distributions in FGMs for high temperature applications. Thermal shock fracture of a FGM plate is analyzed when the plate is suddenly exposed to an environmental medium of a different temperature. The admissible temperature jump that the materials can sustain is studied using stress-based and fracture-toughness-based failure criteria. The critical parameters governing the level of the transient thermal stress in the medium are identified. The thermal shock resistance of the FGMs is analyzed using both maximum local tensile stress and maximum stress intensity factor criteria.