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 ...

The propagation of cracks in graded materials under monotonic and cyclic loading was investigated via experiment and simulation. Graded alumina/epoxy composite specimens exhibiting a variation in composition from 5% to 65% epoxy, representing a twenty-fold variation in Young’s modulus, across a region of width between 6 and 20 mm, were produced by a multistep infiltration technique. Crack initi...

In the present research, a fully Automatic crack propagation as one of the most complicated issues in fracture mechanics is studied whether there is an inclusion or no inclusion in the structures. In this study The Extended Finite Element Method (XFEM) is utilized because of several drawbacks in standard finite element method in crack propagation modeling. Estimated Crack paths are obtained by ...

The present paper deals with the mixed mode fracture analysis of a weakened orthotropic half-plane with multiple cracks propagation. The orthotropic half-plane contains Volterra type glide and climb edge dislocations. It is assumed that the medium is under in-plane loading conditions. The distributed dislocation technique is used to obtain integral equations for the dynamic problem of multiple ...

Crack propagation during the indentation test of a ferroelectric single crystal is simulated using a phase-field model. This model is based on variational formulations of brittle crack propagation and domain evolution in ferroelectric materials. Due to the high compressive stresses near the indenter contact faces, a modified regularized formulation of the variational brittle fracture is coupled...

Background: One of the current problems in studying the mechanical properties and behavior of structurally inhomogeneous media with cracks is the characterization of acoustic wave propagation. This is especially important in Geomechanics and prognosis of earthquakes. Methods: In this work, the authors propose an approach that could simplify characterization of wave propagation in medium with cr...

Objectives To determine the incidence of crack formation and propagation in apical root dentin after retreatment procedures performed using ProTaper Universal Retreatment (PTR), Mtwo-R, ProTaper Next (PTN), and Twisted File Adaptive (TFA) systems. Materials and Methods The study consisted of 120 extracted mandibular premolars. One millimeter from the apex of each tooth was ground perpendicula...

It is vital for the study of fracturing parameters optimal design and fluids rate forecast to calculate fracture propagation parameters accurately. In order to calculate fracture propagation accurately, in this paper, the model for calculating the value of energy release when the rock body collapses was established basing on catastrophe theory, considering that the collapse of fracturing rock b...

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...

We describe a technique for improving the classification of fragmented cues for cracks. Evidence propagation on Bayesian networks represent search within the context of each cue. The algorithm was applied to a data-set of cracks, and results demonstrate that contextual classification of the cues leads to significantly improved error rates.