Meshfree Galerkin approximations in both two and three dimensions have been used in simulations of dynamic shear band propagation in an asymmetrically impact-loaded prenotched plate. Failure mode switching and failure mode transitions, which have been reported experimentally, are replicated in numerical computations. For intermediate impact speed (25 m=s < V 6 30 m=s), the numerical results sho...

A mesh-free Galerkin simulation of dynamic shear band propagation in an impact-loaded pre-notched plate is carried out in both two and three dimensions. The related experimental work was initially reported by Kalthoff and Winkler (1987), and later re-examined by Zhou et al. (1996a,b), and others. The main contributions of this numerical simulation are as follows: (1) The ductile-to-brittle fail...

Progressive and catastrophic failure in soils has been commonly associated with the phenomenon of the shear band propagation. This paper is an attempt to validate the energy balance approach to modeling of the propagation of a two-dimensional, circular shaped shear band. This shear band can be observed in a shear blade test, performed in the novel shear-blade apparatus. The simplified analytica...

The structural origins for the high plasticity of a Zr53Cu18.7Ni12Al16.3 (at.%) bulk metallic glass are explored. Under plastic flow conditions, in situ synchrotron high-energy X-ray diffraction reveals that the atomic strain saturates to the closest packing in the longitudinal direction of the applied load while atoms yield in the transverse plane. Scanning electron microscopy investigation re...

A correlation imaging velocimetry technique is applied to recover displacement fields in a granular material subjected to extended shear. A thick (10 cm) annular sand sample (grain size: 1 mm) is confined at constant pressure (sigma=0.5 MPa) against a rough moving wall displacing at very low speed (delta=83 microm s(-1)). Localization of the strain rapidly forms a shear band (seven particles wi...

Adiabatic shear banding during high speed machining is important to understand material removal mechanisms. This paper investigates the microstructure of adiabatic shear bands (ASBs) in the serrated chips produced during the high speed machining of AISI 1045 hardened steel. Optical microscope, scanning electronic microscope(SEM) and transmission electronic microscope(TEM) were used to explore t...

I study the average deformation rate of an amorphous material submitted to an external uniform shear strain rate, in the geometry known as the split-bottom configuration. The material is described using a stochastic model of plasticity at a mesoscopic scale. A shear band is observed to start at the split point at the bottom, and widen progressively towards the surface. In a two-dimensional geom...

This study investigates the strain localizations associated with Lüders deformation in mild steel using digital image correlation (DIC), a non contact, nondestructive, full field measurement technique for strain mapping. The focus is on the two substantial areas of interest such as shear deformation accompanying strain localization during Lüders instability and the complex morphology of Lüders ...

The propagation of elastic waves in a box under direct shear, filled with glass beads and being sheared at constant rates, is studied experimentally and theoretically. The respective velocities are shown to be essentially unchanged from that in a static granular system under the same pressure and shear stress but without a shear band. Influence of shear band on sound behaviors are also briefly ...