A selection of surface crack problems is presented to provide insights into Stage I and early Stage II fatigue crack growth. Edge cracks at 45o and 90o to the surface are considered for cracks growing in single crystals. Both single crystal slip and conventional plasticity are employed as constitutive models. Edge cracks at 45o to the surface are considered that either (i) kink in the direction...

Pavement crack is the main form of early diseases of pavement. The use of digital photography to record pavement images and subsequent crack detection and classification has undergone continuous improvements over the past decade. Digital image processing has been applied to detect the pavement crack for its advantages of large amount of information and auto detection. The application of digital...

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...

In this paper we address the issue of a creeping wave by investigating a twodimensional configuration which involves a surface-braking crack in a traction free planar backwall. We assume that this back-wall is irradiated by a shear Gaussian beam which is incident at a critical angle and hits the wall away from the crack edge. We show that the generated wave known in the engineering literature a...

An observed minimum in the critical crack initiation load at Poisson’s ratio (ν) of 0.21–0.22 in Na2O–TiO2–SiO2 glasses was investigated. Vickers indentation was used to examine hardness and average cracking length, fracture toughness was measured through the single-edge pre-cracked beam method, and volumes of densification and shear flow around indents were measured using atomic force microsco...

This paper presents a new incremental formulation for predicting the curved growth paths of twodimensional fatigue cracks. The displacement and traction boundary integral equations (BIEs) are employed to calculate responses of a linear elastic cracked body. The Paris law and the principle of local symmetry are adopted for defining the growth rate and direction of a fatigue crack, respectively. ...

Surface cracks are typical defects in high-speed rail (HSR) slab tracks, which can cause structural deterioration and reduce the service reliability of track system. However, question how to effectively detect quantify surface remains unsolved at present. In this paper, a novel crack-detection method based on infrared thermography is adopted rail-track slabs. method, thermogram acquired by an c...

The object of this work is to calculate the T (transition) matrix for a circular crack in a homogeneous, isotropic, linear elastic medium. The T matrix method is a building block technique for multiple scattering, where the T matrix is calculated for each scatterer separately without prior knowledge of the other scatterers (cracks, inclusions, surfaces, etc.).This means that we solve the scatte...

On the ground of manufacturing, sheet metal parts play a key role as they cover about half of the production processes. Sheet metals are commonly obtained from rolling and forming processes which causes misalignment of micro structure resulting obvious anisotropic characteristics and micro cracks. Presence of micro cracks poses serious attention, when stresses at the tip reach to the critical v...

The chipping process in a brittle material subjected to a uniformly applied edge load has been investigated. The present analysis extends earlier work by recognizing that as the chip is formed it may bend and change the loading at the crack tip. This geometry change introduces a nonlinear effect and has significant influence on the phenomenon. The nonlinear effect was demonstrated by incorporat...