A major part of fracture mechanics is concerned with studying the initiation and propagation of fatigue cracks. This typically requires constant monitoring of crack growth during fatigue cycles which necessitates automation of the whole process. If the rate of crack growth can be determined the experimenter can vary externally controlled parameters such as load level, load cycle frequency and s...

Although it is well known that Al-Zn-Mg-Cu alloys are susceptible to intergranular environment-assisted cracking (EAC) in some temper conditions, the relative contribution of hydrogen embrittlement (HE) and anodic dissolution (AD) to the crack advance process remains uncertain. This work reports the results of combining experimental and modeling data of crack potentials to help elucidate the ro...

The extended finite element method (X-FEM) is a numerical method for modeling strong (displacement) as well as weak (strain) discontinuities within a standard finite element framework. In the X-FEM, special functions are added to the finite element approximation using the framework of partition of unity. For crack modeling in isotropic linear elasticity, a discontinuous function and the two-dim...

In this paper, a two-dimensional computational model is proposed for predicting the initiation position and propagation path of subsurface crack of spur gear tooth flank. In order to simulate the contact of teeth, an equivalent model of two contacting cylinders is used. The problem is assumed to be under linear elastic fracture mechanic conditions and finite element method is used for numerical...

Ultrasonic methods have been implemented for in situ sizing of fatigue cracks near fastener holes. These techniques, however, only provide an estimate at the time of the measurement and cannot predict the remaining life of the structure. In contrast, statistical crack propagation approaches model the expected fatigue life based on worst-case fatigue process assumptions. The authors have recentl...

Hydraulic fracturing is used in the oil industry in order to increase the index of production and processing in the wells whose efficiencies have been dropped due to a long-term harvest or the rocks around the wells are of low permeability. Since the hydraulic fracturing operation is costly, it is of special importance to the project managers to determine the pressure required for hydraulic fra...

In this study, single-edge cracked uniaxial specimens with an initial crack length of 0.1 in or 0.3 in and wedge-shaped sheet specimens with an initial crack length of 0.3 in were tested at a constant displacement rate of 50 in/min under 1000 psi confining pressure. The specimens were made of a highly filled polymeric material, containing 86% by weight of hard particles embedded in a rubbery ma...