We present a surface stacking fault (SSF) energy approach to predicting defect nucleation from the surfaces of surface-dominated nanostructure such as FCC metal nanowires. The approach leads to a criterion that predicts the initial yield mechanism via either slip or twinning depending on whether the unstable twinning energy or unstable slip energy is smaller as determined from the resulting SSF...

Dislocation mediated plasticity in the α phase of the energetic molecular crystal cyclotrimethylene trinitramine (RDX) was investigated using a combination of atomistic simulations and the Peierls-Nabarro (PN) model. A detailed investigation of core structures and dislocation Peierls stress was conducted using athermal atomistic simulations at atmospheric pressure to determine the active slip s...

The study of the micro-plastic behavior of rough surface contact is the critical link towards a fundamental understanding of contact, friction, adhesion, and surface failures at small length scales. In the companion paper (Yu et al., J. Mech. Phys. Solids 55, 489-516, 2007), we have studied the onset of surface yielding due to single-dislocation nucleation from a stepped surface under adhesive ...

The ground motion and damage caused by the 2015 Gorkha, Nepal earthquake can be characterized by their widespread distributions to the east. Evidence from strong ground motions, regional acceleration duration, and teleseismic waveforms indicate that rupture directivity contributed significantly to these distributions. This phenomenon has been thought to occur only if a strike-slip or dip-slip r...

We describe a model based in continuum mechanics that reduces the study of a significant class of problems of discrete dislocation dynamics to questions of the modern theory of continuum plasticity. As applications, we explore the questions of the existence of a Peierls stress in a continuum theory, dislocation annihilation, dislocation dissociation, finite-speed-of-propagation effects of elast...

We have performed multimillion-atom molecular dynamics simulations of nanoindentation on cubic silicon carbide !3C-SiC" surfaces corresponding to three different crystallographic directions, !110", !001", and !111", using pyramidal-shaped Vickers indenter with 90° edge angle. Load-displacement !P-h" curves show major and minor pop-in events during loading. Detailed analysis of the !110" indenta...

The three notorious earthquakes of 1999 in Turkey Kocaeli and Düzce and Taiwan Chi-Chi , having offered numerous examples of surface fault rupturing underneath civil engineering structures, prompted increased interest in the subject. This paper develops a nonlinear finite-element methodology to study dip–slip “normal” and “reverse” fault rupture propagation through sand. The procedure is verifi...

Normal faulting earthquakes play an important role in the deformation of continents, and pose significant seismic hazard, yet important questions remain about their mechanics. We use InSAR and bodywave seismology to compute dislocation models and centroid moment solutions for four normal-faulting earthquakes (Mw 5.7–6.2) that occurred in the Pumqu-Xainza Rift (PXR), southern Tibet, a region whe...

The role of geometrically necessary dislocations in providing macroscopic strengthening is reviewed with particle reinforcement as an example. The general relation between the Nye tensor and slip along a curvilinear slip line net is derived to emphasise the importance of curvature of slip lines upon the rate of dislocation storage. 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. Al...

DESCRIPTION A 26-year-old right-handed man presented with pain in his right ring finger after a physical altercation. Deformity and swelling in the distal interphalangeal (DIP) joint was evident. There was no open injury or sensory loss; flexion and extension were limited secondary to pain. X-ray showed posterior dislocation of the ring finger DIP joint without fracture.