A simple model of dynamic cleavage under longitudinal shear deformation is analyzed as an attempt to understand how ancient lapidaries might have produced smooth cleaved surfaces. Attention is concentrated on the time signature of the load applied to the specimen in order to maintain a constant stress intensity factor (or energy release rate) at the crack tip as it propagates away from the loca...

Turbo-generator shafts are often subjected to complex dynamic torsional loadings, resulting in generation and propagation of circumferential cracks. Mode III fatigue crack growth generally results in a fracture surface consisting of peaks and valleys, resembling a factory roof. The fracture surface roughness depends on the material microstructure, the material yield strength, and the applied cy...

In this paper we consider classical and variational of fracture dynamic problems with taking into account a contact interaction of the crack edges. An algorithm for the solution of the elastodynamic contact problem with unilateral constrain has been developed. It arises from the boundary variational principle of elastodynamics for bodies with cracks and unilateral constrains on their sides. Som...

Effects of dislocation emission from a mode I crack and of pinning distances on the behavior of the crack and on fracture toughness in aluminum were studied by using the Molecular Statics Technique with atomic interactions described in terms of the Embedded Atom Method. It was found that aluminum is a ductile material in which the cracks generate dislocations, blunting the cracks. The blunting ...

In this article, the size effect on the dynamic behavior of a simply supported multi-cracked microbeam is studied based on the Modified Couple Stress Theory (MCST).  At first, based on MCST, the equivalent torsional stiffness spring for every open edge crack at its location is calculated; in this regard, the Stress Intensity Factor (SIF) is al...

the contents of as, cd, cu and mo were determined in soil surrounding meyduk tailings dam based on 21 surface soil samples. assessment of toxic element pollution in studied soil samples needs knowledge of pre-anthropogenic metal concentration to act as a reference against which measured values could be compared. estimating the background values was executed by sampling rocks adjacent to soil sa...

This study presents an in-depth investigation of interface modeling techniques in ordinary state-based peridynamics (OSB-PD). By performing numerical examples, the accuracy each technique is investigated by comparison with finite element solutions for simple bimaterial problems. Subsequently, capabilities OSB-PD treating material interfaces complicated geometries are demonstrated solving variou...

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 order to quantitatively characterize the enhancement of hole mobility of strained silicon under different stress intensity conditions, changes of hole effective mass should be studied. In the paper, strained silicon under in-plane biaxially tensile strain based on (0 0 1) substrate and longitudinal uniaxially compressive strain along h1 1 0i are investigated thoroughly. By solving the Hamilt...