BACKGROUND Slow crack growth can be described in a v (crack velocity) versus KI (stress intensity factor) diagram. Slow crack growth in ceramics is attributed to corrosion assisted stress at the crack tip or at any pre-existing defect in the ceramic. The combined effect of high stresses at the crack tip and the presence of water or body fluid molecules (reducing surface energy at the crack tip)...

The vibration behavior of an atomic force microscope [AFM] cantilever with a crack during the nanomachining process is studied. The cantilever is divided into two segments by the crack, and a rotational spring is used to simulate the crack. The two individual governing equations of transverse vibration for the cracked cantilever can be expressed. However, the corresponding boundary conditions a...

The paper presents a computational approach and numerical data which facilitate the use of the smeared-tip method for cohesive fracture in large enough structures. In the recently developed K-version of the smeared tip method, the large-size asymptotic profile of the stress intensity factor density along a cohesive crack is considered as a material characteristic, which is uniquely related to t...

All current experimental methods for determination of stress intensity factors are based on the assumption that the state of stress near the crack tip is plane stress. Therefore, these methods rely on strain and displacement measurements made outside the near crack tip region affected by the three-dimensional effects or by process zone. In this paper, we develop and validate an experimental pro...

All current experimental methods for determination of stress intensity factors are based on the assumption that the state of stress near the crack tip is plane stress. Therefore, these methods rely on strain and displacement measurements made outside the near crack tip region affected by the three-dimensional effects or by process zone. In this paper, we develop and validate an experimental pro...

Whether and how fracture mechanics needs to be modified for small length scales and in systems of reduced dimensionality remains an open debate. Here, employing in situ transmission electron microscopy, atomic structures and dislocation dynamics in the crack tip zone of a propagating crack in two-dimensional (2D) monolayer MoS2 membrane are observed, and atom-to-atom displacement mapping is obt...

A solution is given for the thermoelastic stress field due to the obstruction of a uniform heat flux by a plane crack in a generally anisotropic body. A Green's function formulation is used to reduce the problem to a set of singular integral equations which are solved in closed form. When the crack is assumed to be traction free, the crack opening displacement is found to be negative over one h...

Considered is the interaction of macro-and micro-cracks in an anisotropic piezoelectric solid. The GreenÕs function and principle of superposition are used to formulate a system of singular integral equations for solving the unknown temperature discontinuity and elastic displacement-electric potential. The residual heat ̄ux, stress and electric displacement on the microcrack are evaluated direc...

This paper treats the interactions between a main crack and a rnicrocrack in an anisotropic piezoelectric solid. Based on the Green's function approach and the principle of superposition, a system of singular integral equations for the unknown temperature discontinuity defined on each crack face is developed and can be solved numerically. In the analysis, the residual heat flux, stress and elec...

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...