Y. Hu*, N.K. Kar andS.R. Nutt Gill Composites Center, Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California Abstract: The mechanical response of unidirectional composites subject to uniaxial transverse compressive loads was measured and analyzed by finite element simulation. Consistency in failure plane orientation was observed when...

MARCHAND and Duffy have reported detailed measurements of the temperature and strain as a shear band develops in a HY-100 steel. Assuming their torsional tests in thin-wall tubes can be adequately modeled by a viscoplastic block undergoing overall adiabatic simple shearing deformations. we investigate the effect of modeling the viscoplastic response of the material by a-power law. and flow rule...

Owing to a lack of microstructure, glassy materials are inherently strong but brittle, and often demonstrate extreme sensitivity to flaws. Accordingly, their macroscopic failure is often not initiated by plastic yielding, and almost always terminated by brittle fracture. Unlike conventional brittle glasses, metallic glasses are generally capable of limited plastic yielding by shear-band sliding...

Employing ab initio electronic structure calculations, we predict that trigonal tellurium consisting of weakly interacting helical chains undergoes a trivial insulator to strong topological insulator (metal) transition under shear (hydrostatic or uniaxial) strain. The transition is demonstrated by examining the strain evolution of the band structure, the topological Z2 invariant and the concomi...

The tensile-strained Ge quantum dot (QD) is proposed as a new route for the realization of direct band gap conversion in Ge. Ge QDs were successfully grown on an InP substrate by molecular beam epitaxy. The strain field in the QDs were analyzed by high resolution transmission electron microscopy and simulated by the finite element method based on the measured geometries. The strain field in the...

A splitting between equivalent valleys larger than the spin splitting was recently reported in a gate confined electron system in thin Si films grown on SiGe substrate [1]. This degeneracy lifting reduces scattering and improves the coherence time. The valley splitting larger than the spin splitting opens a way to build spin qubits, which makes silicon-based quantum devices promising for future...

ÐTi±Si mixtures were subjected to high-strain-rate deformation at a pressure below the threshold for shock-wave initiation. Whereas the collapse of interparticle pores did not initiate reaction, regions of localized macro-deformation initiated reaction inside shear bands at suciently high strains (g010), and propagation of the reaction through the entire specimen at higher strains (g020±40). T...

The interplay between shear band (SB) formation and boundary conditions (BC) is investigated in wormlike micellar systems (CPyCl-NaSal) using ultrasonic velocimetry coupled to standard rheology in Couette geometry. Time-resolved velocity profiles are recorded during transient strain-controlled experiments in smooth and sandblasted geometries. For stick BC standard SB is observed, although depen...

The k·p theory allows to describe the band structure analytically. After the pioneering work by Luttinger and Kohn [1] the six-band k·p method has become widely used to model the valence band in silicon. The conduction band in silicon is usually approximated by three pairs of equivalent minima located near the Xpoints of the Brillouin zone. It is commonly assumed that close to the minima the el...

We briefly review and re-interpret recent experiInental results on shear-induced inhoInogeneous flows in coInplex fluids. These are usually explained in terIns of aInechanical instability of the non-linear flow regiIne. However, in at least two respects, the robustness of the two-state banded-flow regiIne and the kinetics of band forInation under shear, they present striking analogies with ordi...