background:  due to difficulty in obtaining anatomical reduction, management of the unstable intertrochanteric fractures in elderly osteoporotic patients is challenging. the purpose of this study is to compare the results of hip arthroplasty (total, hemi, or bipolar) with dhs in the elderly patients with unstable intertrochanteric fractures.   methods:  we prospectively studied and followed-up ...

Fracture propagation, especially for fractures emanating from inclined wellbores and closed natural fracture often involves Mode I, Mode II, and at times Mode III fracture pattern simultaneously. In this paper a Virtual Multidimensional Internal Bond (VMIB) model is presented to simulate 3D mixedmode fracture propagation. To represent the contact and friction between fracture surfaces, a threed...

numerical methods such as boundary element and finite element methods are widely used for the stress analysis in solid mechanics. this study presents boundary element method based on the displacement discontinuity formulation to solve general problems of interaction between hydraulic fracturing and discontinuities. the crack tip element and a higher order boundary displacement collocation techn...

We describe experiments on the dynamic fracture of the brittle plastic, PMMA. The results suggest a view of the fracture process that is based on the existence and subsequent evolution of an instability, which causes a single crack to become unstable to frustrated microscopic branching events. We demonstrate that a number of long-standing questions in the dynamic fracture of amorphous, brittle ...

Rapid development of engineering activities expands through a variety of rock engineering processes such as drilling, blasting, mining and mineral processing. These activities require rock dynamic fracture mechanics method to characterize the rock behavior. Dynamic fracture toughness is an important parameter for the analysis of engineering structures under dynamic loading. Several experimental...

Fracture behavior of Zr55Cu30Al10Ni5 bulk metallic glass was investigated under quasi-static compression at strain rate of 10/s using an Instron testing machine and dynamic split Hopkinson bar (SHPB) compression with strain rate of about 1900–4300/s. Pronounced strain softening, especially past the peak stress, was observed under SHPB tests and compared with the distinct flow serrations under q...

The experimentally determined marked rise of the stress intensity factor required to initiate crack propagation in brittle solids under variably high loading rates, is analyzed. This problem of fracture initiation at the tip of a crack is considered in terms of activating a flaw at some distance away from the tip. By using a semi-infinite crack in an unbounded two-dimensional solid subjected to...

We develop a finite-element method for the simulation of dynamic fracture and fragmentation of thin-shells. The shell is spatially discretized with subdivision shell elements and the fracture along the element edges is modeled with a cohesive law. In order to follow the propagation and branching of cracks, subdivision shell elements are pre-fractured ab initio and the crack opening is constrain...

The effect of loading rate on the plane stress fracture toughness properties of a 3.2-mm thick 2219-T87 aluminum alloy plate was investigated with center-cracked panels. Plane-stress J-resistance curves were generated at a constant displacement rate of 10-6 and 5.7 m s-l. Dynamic fracture testing was performed with a coupled pressure plates technique. Fracture initiation and propagation toughne...