During propagation of brittle cracks in silicon single crystal,

Throughout this paper the normal n denotes the interior normal direction; i.e., n = ( f (x1); 1)= p 1 + jf (x1)j when x approaches from above (denoted by ) and n = (f (x1); 1)= p 1 + jf (x1)j from below (denoted by ). In a recent paper [2] the present authors studied the asymptotic behavior of any solution of (1.2){(1.4) in a neighborhood of the tip X(t). Taking for simplicity t = 0 and assumin...

This paper presents numerical analysis of stress intensity factors (SIFs) of inclined cracks due to mechanical mismatches. According to literature survey, tremendous amounts of SIFs can be found elsewhere. However, the SIFs for inclined cracks are difficult to obtain especially when mechanical mismatch at the crack interface are considered. ANSYS finite element program is used to model the crac...

Cost-effective NDE of the vast length of ageing railway track around the world remains challenge for the community. Since continuously welded railway lines may be thought of as one-dimensional elastic waveguides, they are natural candidates for guided wave ultrasound, which offers the potential to interrogate a large length of rail from a single position. Continuously welded rail is installed i...

A general method to calculate the tangential stiffneis matrix of a structure with a system of interacting propagating cracks is presented. With the help of this matrix. the conditions of bifurcation, stability of state and stability of post-bifurcation path are formulated and the need to distinguish between stability of state and stability path is emphasized. The formulation is applied to symme...

Recent analysis of gas outflow histories at wellheads shows that the hydraulic crack spacing must be of the order of 0.1 m (rather than 1 m or 10 m). Consequently, the existing models, limited to one or several cracks, are unrealistic. The reality is 10(5)-10(6) almost vertical hydraulic cracks per fracking stage. Here, we study the growth of two intersecting near-orthogonal systems of parallel...

Propagation of monochromatic elastic waves across cracks is investigated in 1D, both theoretically and numerically. Cracks are modeled by nonlinear jump conditions. The mean dilatation of a single crack and the generation of harmonics are estimated by a perturbation analysis, and computed by the harmonic balance method. With a periodic and finite network of cracks, direct numerical simulations ...