Influence of layer thickness on the stress distribution in the vicinity of a crack tip is examined, taking into account the fact that the conventional stress intensity factor concept becomes invalid if the thickness of the layer is not much more than the size of the fracture process zone. An eigen-problem is considered which is characterized by two asymptotes. The first is a near one; it is for...

-Properties of elastic solutions to interface crack problems are discussed in both the open formulation, in which the crack faces are assumed to be traction-free and interpenetration is permitted, and the unilateral formulation, where a contact zone is generally established adjacent to the crack tips. It is shown that if the contact zone is sufficiently small compared with the other dimensions ...

A B S TR AC T This paper presents an incremental elastic-plastic finite element solution to the problem of small scale yieldmg near a crack in plane strain for a non-hardening material. Emphasis is placed on the design of finite elements which allow accurate reproduction, m a numerical solution, of the detailed structure of the near crack tip stress and strain fields, as understood from previou...

Plasticity-induced, roughness-induced and oxide-induced crack closures are reviewed. Special attention is devoted to the physical origin, the consequences for the experimental determination and the prediction of the effective crack driving force for fatigue crack propagation. Plasticity-induced crack closure under plane stress and plane strain conditions require, in principle, a different expla...

Concrete and cracking are nearly synonymous despite our best efforts and intentions. Relationships between cracking and the stress states that lead to cracking can be instructive. In an effort to better understand these relationships, X-ray microtomography was used to make high-resolution three-dimensional digital images of small concrete specimens under load. Using 3D image analysis, quantitat...

Dynamic crack propagation drives catastrophic solid failures. In many amorphous brittle materials, sufficiently fast crack growth involves small-scale, high-frequency microcracking damage localized near the crack tip. The ultrafast dynamics of microcrack nucleation, growth, and coalescence is inaccessible experimentally and fast crack propagation was therefore studied only as a macroscale avera...

This article concerns an extension of the topological sensitivity (TS) concept for 2D potential problems involving insulated cracks, whereby a misfit functional J is expanded in powers of the characteristic size a of a crack. Going beyond the standard TS, which evaluates (in the present context) the leading O(a) approximation of J , the higher-order TS established here for a small crack of arbi...

Automated pavement crack detection is a challenging task that has been researched for decades due to the complicated pavement conditions in real world. In this paper, a supervised method based on deep learning is proposed, which has the capability of dealing with different pavement conditions. Specifically, a convolutional neural network (CNN) is used to learn the structure of the cracks from r...

High-cycle fatigue (HCF), involving the premature initiation and/or rapid propagation of small cracks to failure due to high-frequency cyclic loading, has been identified as one of the leading causes of turbine engine failures in aircraft. In this work, we consider the feasibility of using grain-boundary engineering to improve the HCF properties of a polycrystalline nickel-base superalloy, René...

Purpose: In the present paper a crack arrest model is proposed for an infinitely long narrow poled piezoelectric strip embedded with a centrally situated finite hairline straight crack. Design/methodology/approach: The ceramic of the strip is assumed to be mechanically brittle and electrically ductile. Combined mechanical and electrical loads applied at the edge of the strip open the rims of th...