R Ghajar - Department of Mechanical Engineering, K.N. Toosi University ,Tehran, Iran
S Peyman - Department of Mechanical Engineering, K.N. Toosi University ,Tehran, Iran
J Sheikhi - Department of Civil Engineering ,Razi University , Kermanshah, Iran
M Poorjamshidian - Department of Mechanical Engineering, Kashan University ,Kashan, Iran

In this paper, the interface crack of two non-homogenous functionally graded materials is studied. Subsequently, with employing the displacement method for fracture of mixed-mode stress intensity factors, the continuous variation of material properties are calculated. In this investigation, the displacements are derived with employing of the functional graded material programming and analysis of isoparametric finite element; then, with using of displacement fields near crack tip, the mixed-mode stress intensity factors are defined. In this present study, the problems are divided into homogenous and non-homogenous materials categories; and in order to verify the accuracy of results, the analytical and numerical methods are employed. Moreover, the effect of Poisson s ratio variation on mixed-mode stress intensity factors for interface crack be examined and is shown in this study. Unlike the homogenous material, the effect of Poisson’s ratio variations on mixed-mode stress intensity factors at interface crack between two nonhomogenous is considerable.

Interface crack, Displacement method, Nonhomogeneous materials