The effects of dynamic loading on crack breathing mechanisms are not yet thoroughly examined in literature. This paper introduces a parameter relating crack direction to bending load direction in order to model breathing behaviour of fatigue cracks subject to mass unbalance. Crack states (open, partial and closed) for shafts subject to weight-to-unbalance force ratios of 0.5, 1 and 2 and unbala...

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...

The use of microwave technique has proved to be a viable means for crack detection and sizing surface cracks in metals. In this technique, the surface of the specimen is interrogated with a radiating open-ended waveguide probe and a crack is assumed to be a simple short-circuited rectangular waveguide, causing peturbations in the probe reflection coefficient. Since the growth of fatigue in meta...

An efastic half-plane containing a su~ace-b~ak~og crack normal to the free surface, subjected to loading by uniform tractions over a given length af its surface, is considered. The tractions consist of pressure, constant in time, and a shear load, varying sinu~idaily in time, both applied adjacent to the crack. This geometry approximates the classical fretting problem with a resulting fatigue c...

Two different optical configurations were developed and are described. The first is a laser profiling system that is used for transverse profile acquisition for rut detection purposes. The second uses an autosynchronized laser scanning sensor for crack detection Both these systems have been installed on inspection vehicles and have been tested. Tests have shown results that have a very good cor...

The inspection of various structures often detects a fatigue cracks developed during long service life. These fatigue cracks significantly reduce remaining fatigue life and fatigue strength. Influence of the initial fatigue cracks size in non-load-carrying fillet-welded one-sided transverse attachment joints on the remaining fatigue life and fatigue strength is considered in this paper. A compu...

Keywords: Concrete structures Shear strength Aggregate interlock Residual tensile strength of concrete Dowel action Arching action Critical Shear Crack Theory Size effect Strain effect a b s t r a c t Many theories and empirical formulae have been proposed to estimate the shear strength of reinforced concrete members without transverse reinforcement. It can be noted that these approaches differ...

In this paper, the stress intensity factor (SIF) variations along an arbitrarily developing crack front, the non-planar fatigue-crack growth patterns, and the fatigue life of a round bar with an initially straight-fronted surface crack, are studied by employing the 3D symmetric Galerkin boundary element method-finite element method (SGBEM-FEM) alternating method. Different loading cases, involv...

a crack depth in mm, same as x â measurement system response, 1 – R– A(x) system model for evolving crack depth x A(n) linearised system model at measurement set n B(x) measurement model giving normalised energy ratio R– as a function of crack depth x B(n) linearised measurement model at measurement set n B(R) inverse measurement model giving crack depth x as a function of normalised energy rat...