Objective This study aimed to explore the functional connectivity of the default mode network (DMN) in crack-cocaine users, in comparison with that observed in age-matched non-drug-using controls. Materials and Methods Inpatient crack-cocaine users who had been abstinent for at least four weeks and age-matched non-drug-using controls underwent resting state functional magnetic resonance imagi...

This paper present a mechanical characteristics on fatigue crack propagation in Aluminium Plate based on strain and stress distribution using the abaqus software. The changes in shear strain and stress distribution during the fatigue cycle with crack growth is identified. In progressive crack in the strain distribution and the stress is increase in the critical zone. Numerical Modal analysis of...

In this study, the problem of finding the limiting load in infinite plates with internal cracks is extended to the non-linear field. In particular, results concerning concrete plates in bi-axial loading are shown. The analysis is performed in discrete form, by means of the Cell Method. The discrete analysis allows us to identify the crack initiation without using the stress intensity factors. T...

A new algorithm is described which extends the material point method (MPM) to allow explicit cracks within the model material. Conventional MPM enforces velocity and displacement continuity through its background grid. This approach is incompatible with cracks which are displacement and velocity discontinuities. By allowing multiple velocity fields at special nodes near cracks, the new method (...

The theory of crack propagation in orthotropic media is developed by applying the theory of incremental deformations in the vicinity of a state of initial stress. This is carried out in the context of a new approach to analytical methods and a physical analysis which takes into account plastic deformation under prestress. The state of initial stress is triaxial along the directions of elastic s...

One of the most important problems in the fatigue analysis and design of aircraft structures is the prediction of the fatigue crack growth in service. Available in-service inspection data for various types of aircraft indicate that the fatigue crack damage accumulation in service involves considerable statistical variability. In this paper, we consider the problem of estimating the minimum time...

For many fracture problems of practical engineering importance, the three-dimensional effects are significant and a three-dimensional analysis for the problems is thus required. In this paper, an endochronic theory coupled with anisotropic damage is first established, which is actually an elasto-plastic damage theory coupled with isotropic-nonlinear kinematic hardening. The ductile damage evolu...

Avoidance of cracking damage due to hydration is an important objective in the design of nuclear reactor containments. Assessment of the safety against cracking requires a realistic material model and its effective numerical implementation. Toward this goal, the paper develops a comprehensive material model which includes approximate simulation of cracking based on the principles of cohesive fr...

Increased traffic speeds and axle loads on modern railways enhance rail track degradation. To eliminate track failure due to rail defects, a condition monitoring system requires methods for the early detection of defects which grow in service. Acoustic emission (AE) monitoring is the only non-destructive technique which might be applied online to study the defect growth under traffic loading. H...