The aim of the present paper is a systematic elaboration of a three dimensional finite element analysis tool for discontinuous fracture in brittle solids. Brittle or quasi-brittle fracture usually occurs when a material reaches the limit of its strength and no plastic deformation has been observed prior to failure. In this novel approach, this kind of failure is characterized by three sets of g...

A three-dimensional failure initiation criterion in brittle materials containing a sharp V-notch is presented and validated by experiments. It is based on simultaneous fulfilment of the stress requirement and a finite fracture mechanics energy release rate (ERR) requirement. Since the ERR cannot determine failure initiation direction for dominant mode III loading, the failure initiation orienta...

A typical dynamometer drive shaft was damaged during its working condition. This failure was repeated in four cases. In the present article, a failure analysis of a dynamometer drive shaft has been performed. To analyze the failure, the material investigation was carried out by scanning electron microscopy (SEM) images. Additionally, the micro-structure of the failed coupling shaft was photogra...

According to the damage mechanics theory and Lemaitre strain equivalence theory, because most rock materials are brittle materials, Griffith strength criterion has good applicability describe fracture failure of from perspective energy. Using a new method micro-element based on criterion, assuming obeys Weibull distribution, true triaxial constitutive model softening reflecting whole process is...

Diffusion dominates the creep deformation at low stress range for high chromium steel P91. Brittle creep fracture is caused by cavity nucleation, growth and coalescence of cavities and large precipitates (Laves phase and M23C6) at grain boundary under low stress range. At low stress range, a linear relation between strain at failure and different stresses has been described. Moreover, the minim...

This paper discusses Coulomb failure criteria for brittle deformation of intact rock and fault gouge. Data are presented from laboratory experiments designed to identify the critical gouge layer thickness required to effect a transition from the standard Coulomb criterion to a modified failure law (referred to as Coulomb plasticity) appropriate for simple shear of a gouge layer. Experiments wer...

An initiation criterion is developed for a discrete constitutive equation model of material failure. The decohesion constitutive model is combined with elasticity and implemented in the numerical material-point method. The complete numerical proceedure is used to study spall failure in brittle materials. A one-dimensional analytical solution for a bar subjected to a sinusoidal pulse is derived ...

The energy release rate (ERR) proposed by Irwin based on a theory by Griffith [1, 2] has been extensively used as a fracture criterion in 2D for brittle domains. Under in-plane mixed mode loading (modes I+II), the direction of crack initiation from cracks and sharp V-notches was determined by the orientation at which the ERR attains its maximum. Using the newly developed asymptotic expansion pr...

In the present work, a novel cohesive discontinuous Galerkin (CDG) method is proposed to model interfacial failure of brittle materials. Before failure, an incomplete interior penalty (IIPG) variant (DG) family applied for linear elasticity. Once criterion met, extrinsic zone (CZ) captures behavior interface. Through application DG in combination with reduced integration on boundary terms, lock...