The explosion process of explosives in a borehole applies a very high pressure on its surrounding rock media. This process can initiate and propagate rock fractures, and finally, may result in the rock fragmentation. Rock fragmentation is mainly caused by the propagation of inherent pre-existing fractures of the rock mass and also from the extension of the newly formed cracks within the intact ...

Although clinical bone fractures occur predominantly under impact loading (as occurs during sporting accidents, falls, high-speed impacts or other catastrophic events), experimentally validated studies on the dynamic fracture behavior of bone, at the loading rates associated with such events, remain limited. In this study, a series of tests were performed on femoral specimens obtained post-mort...

Experimental techniques for high-strain-rate measurements and for the study of impactrelated problems are described. An approach to classifying these experimental techniques is presented, and the state-of-the-art is briefly described. An in-depth description of the basis for high-strain-rate experiments is presented, with an emphasis on the development of a range of strain rates and a range of ...

We present a method to reduce mesh bias in dynamic fracture simulations using the fi nite element method withadaptive insertion of extrinsic cohesive zone elements along element boundaries. The geometry of the domaindiscretization is important in this setting because cracks are only allowed to propagate along element facets andcan potentially bias the crack paths. To reduce mesh...

background: at present, there is no consensus on an appropriate treatment modality for intertrochanteric fractures in the elderly with background diseases. the aim of the present study was to compare treatment outcomes of intertrochanteric fractures reduced with dynamic hip screws (dhs) and bipolar hemiarthroplasty in elderly patients with background medical conditions. methods: in this randomi...

We describe the historical development of large-scale nonequilibrium molecular-dynamics (NEMD) computer simulations of fracture at Los Alamos. We have found that dynamic crack propagation leads to energy buildup that seeds instabilities, such as dislocation emission and branching. Recent three-dimensional simulations have shed light on ductile fracture mechanisms, including sequences of disloca...

In this study, 5052 Al–Mg alloy was pre-treated and friction stir processing (FSP) was then performed on the specimens to explore the deformation resistance. The experimental results indicate that the FSP specimens not only had better tensile properties but also better vibration fracture resistance. It is significant that the tensile elongation and deformation resistance tended to increase as t...

Various theories in the past have addressed the correlation of material properties and the respective acoustic emission release during fracture. Whilst these theories yield good predictions for fundamental relationships, they neglect the dynamic displacements during crack formation. This paper presents first results for a new acoustic emission crack source model based on a finite element modell...