Three-dimensional enriched finite elements are used to compute mixed-mode stress intensity factors (SIFs) for three-dimensional cracks in elastic functionally graded materials (FGMs) that are subject to general mixed-mode loading. The method, which advantageously does not require special mesh configuration/modifications and post-processing of finite element results, is an enhancement of previou...

Natural and artificial materials including rocks and cement-based materials such as concrete and cement mortar are affected both physically and chemically by various natural factors known as weathering factors. The freeze-thaw process, as a weathering factor, considerably affects the properties of rocks and concrete. Therefore, the effect of the freeze-thaw process on the physical and mechanica...

This paper presents a new continuum shape sensitivity method for calculating the mixed-mode stress-intensity factors of a stationary crack in two-dimensional, linear-elastic, orthotropic functionally graded materials with arbitrary geometry. The method involves the material derivative concept taken from continuum mechanics, the mutual potential energy release rate, and direct differentiation. S...

This is the first in a series of two papers generated from a study on probabilistic meshless analysis of cracks. In this paper (Part I), a Galerkin-based meshless method is presented for predicting first-order derivatives of stress-intensity factors with respect to the crack size in a linear-elastic structure containing a single crack. The method involves meshless discretization of cracked stru...

In this study, a novel numerical method is proposed for determination of mode-I interlaminar fracture toughness, GIc, in multi-directional (MD) double cantilever beam (DCB) specimens using fracture properties of unidirectional DCB specimens. Two factors, β and Dc are defined to minimize the undesirable effects on strain energy release rate. β describes the difference between maximum and average...

In this paper, topology optimization is utilized for damage detection in three dimensional elasticity problems. In addition, two mode expansion techniques are used to derive unknown modal data from measured data identified by installed sensors. Damages in the model are assumed as reduction of mass and stiffness in the discretized finite elements. The Solid Isotropic Material with Penalization (...

In this paper, two different techniques for mixed-mode type engineering fracture analysis, by using the weight-function method, are presented. These two methods are (a) the virtual crack extension technique (VCE), and (b) the equivalent domain integral method (EDI). For mixed-mode weight-function evaluation, a technique of using two reference load states, both of which cannot be either pure mod...

Modeling of crack propagation by a finite element method under mixed mode conditions is of prime importance in the fracture mechanics. This article describes an application of finite element method to the analysis of mixed mode crack growth in linear elastic fracture mechanics. Crack - growth process is simulated by an incremental crack-extension analysis based on the maximum principal stress c...