Three-dimensional dislocation dynamics simulations are used to study micro-crack interaction with the first micro-structural barrier in face-centred cubic bi-crystals loaded in high cycle fatigue conditions. In the examined configuration, we assumed that micro-crack transmission occurs due to surface relief growth in the secondary grain ahead of the primary crack. This indirect transmission mec...

This paper is concerned with the problem of plastic zone at the tip of an edge crack in an isotropic elastoplastic strip under anti-plane deformations. By means of complex potential and Dugdale model, the stress intensity factor and the size of plastic zone are obtained in closed-form. Furthermore, the analytic solutions for an edge crack at the free boundary of a half-space and a semi-infinite...

The dynamic steady-state propagation of two parallel semi-infinite, mode III cracks is considered for a general, infinite, homogeneous, and isotropic linearly viscoelastic body. A Barenblatt type failure zone is introduced in order to cancel the singular stress and a formula for the energy release rate is derived which provides immediate comparisons with the corresponding single crack problem. ...

A solution for a crack propagating under shear loading in an isotropic viscoelastic medium with different relaxation under volume and shear deformations is presented. The medium is infinite and the semi-infinite crack propagates along the x1-axis at constant speed V , which may take any value up to the speed of dilatational waves. The requisite Riemann-Hilbert problem for the steady-state case ...

A model is provided for crack problem in a functionally graded semi-infinite plate under an anti-plane load. The characteristic of material behavior is assumed to change in a linear manner along the plate length. Also the embedded crack is placed in the direction of the material change. The problem is solved using two separate techniques. Primary, by applying Laplace and Fourier transformation,...

An exact dynamic 2D solution for a concentrated force near a stationary semi-infinite crack in an unbounded plane can be used in the transient analysis of wave-scattering problems. Direct approaches to obtaining the solution, however, are complicated by the existence of a characteristic length. A less direct approach is used here which circumvents these complications. As an example, the dynamic...

The high-cycle fatigue (HCF) of titanium alloy turbine engine components remains a principal cause of failures in military aircraft engines. A recent initiative sponsored by the United States Air Force has focused on the major drivers for such failures in Ti-6Al-4V, a commonly used turbine blade alloy, specifically for fan and compressor blades. However, as most of this research has been direct...