We present a model for the brittle–ductile transition in ferritic steels based on two dimensional discrete dislocation simulations of crack-tip plasticity. The sum of elastic fields of the crack and the emitted dislocations defines an elasto–plastic crack field. Effects of crack-tip blunting of the macrocrack are included in the simulations. The plastic zone characteristics are found to be in a...

Compositionally graded glass-filled epoxy sheets with edge cracks initially along the gradient are studied under dynamic loading conditions. Specimens with monotonically varying volume fraction of reinforcement are subjected to mixed-mode loading by eccentric impact relative to the crack plane. The optical method of Coherent Gradient Sensing and high-speed photography are used to map transient ...

This paper presents a three-dimensional crack initiation analysis in a sidegrooved CT specimen. This is achieved with an endochronic damage model proposed recently by Chow and Chen [ 1,2] and discretized for finite element analysis. The damage model enables the quantification of the progressive damage evolution which would not be otherwise possible using the conventional fracture mechanics anal...

The fracture property of amorphous metal was studied by a large scale molecular dynamics (MD) simulation. The Finnis-Sinclair potential for α-iron was used as an inter-atomic potential. At first, we made a model amorphous metal by melting-rapid quenching simulation. And then a crystal growth simulation in the amorphous was performed. We used circular model, and the cracktip is assumed to be at ...

Ab~act-The ductile vs brittle behaviour of metal-ceramic interfaces is discussed within an atomistic framework, in which the mechanical response of an interfucial crack is assumed to be ultimately controlled by the competition between atomic decohesion and dislocation nucleation ahead of the crack tip. As in later versions of the Rice-Thomson model, this competition may be evaluated in terms of...

Fatigue crack growth is a complex process that involves interactions between many elements ranging across several length scales. This work provides an in-depth, experimental study of fatigue crack growth and the relationships between four of these elements: strain field, microstructure, crack path, and crack growth rate. Multiple data sets were acquired for fatigue crack growth in a nickel-base...

The fracture mechanics of electromechanical materials has been investigated for well over a decade, yet there still exists controversy over the appropriate crack face boundary conditions for non-conducting cracks. In this paper an experimental protocol for measuring the energy release rate in a non-linear reversible electromechanical body is proposed and summarized. The potential results from t...

A traction-displacement relationship that may be embedded into a cohesive zone model for microscale problems of intergranular fracture is extracted from atomistic molecular-dynamics simulations. A molecular-dynamics model for crack propagation under steady-state conditions is developed to analyze intergranular fracture along a flat Σ99 [1 1 0] symmetric tilt grain boundary in aluminum. Under hy...

In this paper, an equivalent domain integral (EDI) method and the attendant numerical algorithms arc presented for the computation of a near-crack-tip field parameter, the vector Jε-integral, and its variation along the front of an arbitrary three-dimensional crack in a structural component. Account is taken of possible non-elastic strains present in the structure; in this case the near-tip Jε-...

In this paper, the fatigue and fracture properties of bovine dentin are evaluated using in vitro experimental analyses. Double cantilever beam (DCB) specimens were prepared from bovine maxillary molars and subjected to zeroto-tension cyclic loads. The fatigue crack growth rate was evaluated as a function of the dentin tubule orientation using the Paris law. Wedge-loaded DCB specimens were also ...