Investigation of dynamic-thermal stress intensity factor in functionally-graded plates having an edge crack

Functionally graded materials (FGMs) are non-homogeneous materials whose properties gradually vary as a function of coordinates. Recently, due to the possibility of applying FGMs in conditions with severe temperature changes, e.g., nuclear reactors, chemical power plants, and space crafts, the interest in investigations on this type of material has increased considerably. Usually, FGMs are designed to tolerate drastic temperature changes and thermal shocks are mainly associated with thermal stresses. Therefore, the occurrence of thermal fracture in FGMs is probable. Consequently, studying the fracture mechanics of this type of material under extreme thermal shocks and dynamic loads has become crucial. This paper studies the first mode stress intensity factor (SIF) in FGM plates with an edge crack under thermal shock and dynamic loading. The plates consist of Nickel (metal) and Zirconia (ceramic) properties on top and bottom, respectively. The finite element method is employed to perform dynamic thermal analyses of the plates. Having known that variations in the amount of metal and ceramic used in producing an FGM plate can change its behavior, different gradients of material properties are applied for modeling the FGM plates. Then, the effects of the variation of the gradients on the dynamic-thermal SIF under thermal shocks and dynamic loadings are examined. One of the novelties of the present study is modeling the required material properties for thermal analyses (heat transfer coefficient, specific heat, and thermal expansion coefficient) and dynamic analyses (elasticity modulus, Poisson's ratio, and density) as functions, which have been rarely considered simultaneously in the previous studies.

کلیدواژه ها:

Functionally-Graded Material ، Edge Crack ، Dynamic-Thermal Stress Intensity Factor ، finite element method