An elastic-plastic analysis is performed for two problems relevant to fracture mechanics: a semi­ infinite body with an edge crack in a far out-of-plane shearing field and an infinite plate under plane stress conditions containing a finite line crack in a remote tensile field. Amplitudes of the dominant singularity in the plastic region at the crack tip, the plastic stress and strain intensity ...

Three techniques for measuring dynamic stress intensity factor time histories of dynamically loaded stationary modeI cracks are compared as applied to dynamically loaded pre-cracked 6Al–4V titanium alloy specimens. The three techniques are crack opening displacement (COD), dynamic strain gage measurement, and coherent gradient sensing (CGS). The stress intensity factor histories are inferred fr...

The optical methods of Caustics, Photoelasticity and Isopachics for the evaluation of the stress intensity factors and the distribution of the principal stresses at a bi-material interface crack-tip, were proposed. The caustics, isochromatic and isopachic fringes are developed from the stress field which results from a stress function X(r, ). When the crack-tip, which is perpendicular to interf...

We consider the Poisson equation −∆u = f with homogeneous Dirichlet boundary condition on a two-dimensional polygonal domain Ω with re-entrant angles. A multigrid method for the computation of singular solutions and stress intensity factors using piecewise linear functions is analyzed. When f ∈ L2(Ω), the rate of convergence to the singular solution in the energy norm is shown to be O(h), and t...

Erythropoietin (Epo)-induced Stat5 phosphorylation (p-Stat5) is essential for both basal erythropoiesis and for its acceleration during hypoxic stress. A key challenge lies in understanding how Stat5 signaling elicits distinct functions during basal and stress erythropoiesis. Here we asked whether these distinct functions might be specified by the dynamic behavior of the Stat5 signal. We used f...

In this paper, influence of riveting process parameters, namely, riveting force, sheet thickness, friction coefficient and clearance fit are investigated on residual stress field and fatigue life of single riveted lap joint of AA2024 type. According to the effect of riveting induced residual stresses on fatigue life of riveted lap joint, these parameters are optimized to maximize the residual s...

The present work investigates the effect of the elliptical three-dimensional (3D) cracks on a pipe with thickness transition, considering internal pressure. Level sets were defined using the extended finite element method (XFEM), the stress intensity factors (SIFs) of 3D cracks were investigated and compared between straight pipes and pipes with thickness transition. The results show that the X...