Debonding of an inclusion from the surrounding matrix in the presence of a nearby crack tip is studied numerically. Finite element models of symmetric three-point bend configurations are implemented in conjunction with a stiffness degradation method and the maximum tensile stress criteria to investigate the influence of debonding on crack tip parameters. The geometry considered is a single edge...

Abstract-Transonic interfacial crack growth in bimaterial systems is analysed, and the asymptotic field around the moving crack tip is obtained by the straightforward approach of analytic continuation. The power of singularity is less than l/2 for anti-plane shear deformation. For in-plane deformation, the power of singularity can be real or complex, depending on the speed of the crack tip. Acr...

Employing Dynamic Discrete Dislocation Plasticity (D3P), an elastodynamic analysis of the shielding of a stationary crack tip by dislocations is studied. Dislocations are generated via FrankRead sources, and make a negligible contribution to the shielding of the crack tip, whereas dislocations generated at the crack tip via homogeneous nucleation dominate the shielding. Their effect is found to...

This paper demonstrates that rapid fracture of ideal brittle lattices naturally involves phenomena long seen in experiment, but which have been hard to understand from a continuum point of view. These idealized models do not mimic realistic microstructure, but can be solved exactly and understood completely. First it is shown that constant velocity crack solutions do not exist at all for a rang...

The mechanisms of fatigue-crack propagation are examined with particular emphasis on the similarities and differences between cyclic crack growth in ductile materials, such as metals, and corresponding behavior in brittle materials, such as intermetallics and ceramics. This is achieved by considering the process of fatiguecrack growth as a mutual competition between intrinsic mechanisms of crac...

It is well known that the near-tip displacement eld on a crack surface can be represented in a power series in the variable p r, where r is the distance to the tip. It is shown herein that the coe cients of the linear terms on the two sides of the crack are equal. Equivalently, the linear term in the crack opening displacement vanishes. The proof is a completely general argument, valid for an a...

A finite-element procedure is developed to analyze plane ductile fracture problems in the presence of largescale yielding near the crack tip. Strain and stress singularities near the crack tip, corresponding to the strainhardening material model, are embedded in elements near the crack tip. The developed elastic-plastic incremental finite-element method is based on a hybrid displacement model. ...

Crack tip dislocations in silicon single crystals were observed by combining high-voltage electron microscopy and electron tomography. Cracks were introduced by an indentation method and dislocations were introduced around the crack tip by keeping the indented sample at high temperatures for several hours. The number of dislocations emitted from the crack tip was controlled by changing the hold...

An anisotropic cohesive model of fracture is applied to the numerical simulation of Coker and Rosakis experiments (2001). In these experiments, a unidirectional graphite–epoxy composites plate was impacted with a projectile, resulting in an intersonic shear-dominated crack growth. The simulations account for explicit crack nucleation––through a selfadaptive remeshing procedure––crack closure an...

We investigate theoretically statistics and thermally activated dynamics of crack nucleation and propagation in a two-dimensional heterogeneous material containing quenched randomly distributed defects. We consider a crack tip dynamics accounting for dissipation, thermal noise and the random forces arising from the elastic interactions of the crack opening with the defects. The equation of moti...