Malzeme Özellikleri Sıcaklığa Bağımlı Olan Izotropik Fonksiyonel Derecelendirilmiş Malzemelerde Bulunan Eğik Çatlakların Gerilme Şiddet Çarpanları Jk-İntegral Yöntemi ile Hesaplanması

Abstract

The main aim of this study is to utilize a Jk-integral for the analysis of inclined cracks located in functionally graded materials (FGMs). The crack is subjected to mixed mode thermal loading. The generalized definition of the Jk-integral over a vanishingly small curve at the tip of an inclined crack is converted to a domain independent form that consists of area and line integrals defined over finite domains. A numerical procedure based on the finite element method is then developed, which allows the evaluation of the components of the Jk -integral, the modes I and II stress intensity factors, energy release rate and the T-stresses at the crack tips. In both thermal and structural analyses, finite element models that possess graded isoparametric elements are created in the general purpose finite element analysis software ANSYS. In the formulation of Jk-integral, all required engineering material properties are assumed to possess continuous spatial variations through the functionally graded medium. The numerical results are compared to the results obtained from Displacement Correlation Technique (DCT). The domain independence of Jk-integral is also demonstrated. Detailed parametric analyses are conducted by considering an inclined crack in an FGM layer that is subjected to steady-state thermal stresses. The results obtained in this study show the effects of relative location, relative crack size, material property profile and the crack inclination angle on stress intensity factors and energy release rate.