A series of massively parallel molecular dynamics simulations with up to 35 million atoms is performed to investigate dislocation emission from a three-dimensional crack. We observe dislocation loops emitted from the crack front|the rst time this has been seen in computer simulations. The sequence of dislocation emission in the process of crack blunting process strongly depends on the crystallo...

In this Letter, we propose a model that demonstrates the effect of a free surface on the lattice resistance experienced by a moving dislocation in nanodimensional systems. This effect manifests in an enhanced velocity of dislocation due to the proximity of the dislocation line to the surface. To verify this finding, molecular dynamics simulations for an edge dislocation in bcc molybdenum are pe...

Plastic deformation mediated by collective dislocation dynamics is investigated in the two-dimensional phase-field crystal model of sheared single crystals. We find that intermittent fluctuations in the dislocation population number accompany bursts in the plastic strain-rate fluctuations. Dislocation number fluctuations exhibit a power-law spectral density 1/f2 at high frequencies f. The proba...

Numerical studies of dislocation pair correlations have played a central role in deriving a continuum theory from the equations of motion of 2D dislocation systems in a mathematically rigorous way. As part of an effort to extend this theory into the full 3D dislocation problem, 3D dislocation pair correlations were studied with discrete dislocation dynamics simulation. As a first approximation,...

The mechanisms of dislocation intersection and strain hardening in fcc crystals are examined with emphasis on the process of junction formation and destruction. Large-scale 3D simulations of dislocation dynamics were performed yielding access for the first time to statistically averaged quantities. These simulations provide a parameter-free estimate of the dislocation microstructure strength an...

Posterior dislocation of the shoulder is a rare injury that occurs secondary to trauma and seizures. Diagnosis is often missed and treatment is challenging. Neglected posterior dislocation is associated with Hill-Sachs lesion which leads to locking of dislocation. Correct diagnosis is achieved by history taking, a physical examination and appropriate imaging. In neglected shoulder dislocation w...

The partial dislocation model for the deformation mechanism of nanocrystalline materials is extended to consider the influence of non-uniform dislocation extension. The non-uniform partial dislocation extension model is more consistent with experimental data than the original partial dislocation model. Additionally, the flow stress obtained from the non-uniform extension model is compared with ...

The incidence of traumatic hip dislocation has increased in recent years as a result of high-energy trauma. Anterior hip dislocation forms less than 10-15% of all traumatic hip dislocations. Only a few case reports describe anterior dislocation along with acetabular fractures. The acetabular fracture involved the anterior wall or column in all such cases. We describe a rare case in which anteri...

Elbow dislocation with ipsilateral diaphyseal fracture of both radius and ulna is a rare injury. However, elbow dislocation with either radius or ulnar diaphyseal fracture is commonly reported. We report an uncommon injury of a 16 years old male who had his elbow dislocation with ipsilateral both bones forearm fractures. Elbow dislocation was reduced and fracture both bones were fixed with dyna...

Employing the empirical embedded-atom method potentials, the evolution of edge and screw dislocation core structure is calculated at different hydrogen concentrations. With hydrogen, the core energy and Peierls potential are reduced for all dislocations. A broaden-core and a quasi-split core structure are observed for edge and screw dislocation respectively. The screw dislocation and hydrogen i...