The atomistic mechanisms active during plastic deformation of nanocrystalline metals are still a subject of controversy. The recently developed approach of combining automated crystal orientation mapping (ACOM) and in situ straining inside a transmission electron microscope was applied to study the deformation of nanocrystalline Pd x Au1- x thin films. This combination enables direct imaging of...

The simulation of high-rate deformation and failure of metals is has traditionally been performed using Lagrangian finite element methods or Eulerian hydrocodes. Lagrangian mesh-based methods are limited by issues involving mesh entanglement under large deformation and considerable complexity in handling contact. On the other hand, Eulerian hydrocodes are prone to material diffusion. In the Mat...

Based on Rayleigh beam theory, the sub-impacts of a free-free beam struck horizontally by a round-nosed rigid mass is simulated by the finite difference method and the impact-separation conditions. In order to obtain the sub-impact force, a uniaxial compression elastic-plastic contact model is employed to analyze the local deformation field on contact zone. It is found that the horizontal impac...

Here we propose a macroscopic model for elasto-plastic composite, characterized by an initial anisotropy, that can evolve during the large plastic deformation. Application to transversely isotropic and orthotropic composites will be also developed. The paper deals with anisotropic finite elasto-plastic 6-models, which accounts for the dissipative nature of the plastic flow, within the construct...

The effect of fibre bundling on the effective transverse properties of unidirectional fibre composites has been investigated by way of finite element method and micromechanics models of fibre bundles. Based on the micromechanical model of single-fibre composites, plane strain models for composites reinforced by fibre bundles are presented. The effective elasto-plastic stress /strain behaviour w...

On microscopic and mesoscopic scales, plastic flow of crystals is characterized by large intrinsic fluctuations. Deformation by crystallographic slip occurs in a sequence of intermittent bursts (’slip avalanches’) with power-law size distribution. In the spatial domain, these avalanches produce characteristic deformation patterns in the form of slip lines and slip bands which exhibit longrange ...

Intermittent plastic deformation in crystals with power-law behaviors has been reported in previous experimental studies. The power-law behavior is reminiscent of self-organized criticality, and mesoscopic models have been proposed that describe this behavior in crystals. In this paper, we show that intermittent plasticity in metals under tensile deformation can be observed in molecular dynamic...

Because of their disordered atomic structure, amorphous metals (termed metallic glasses) have fundamentally different deformation mechanisms compared with polycrystalline metals. These different mechanisms give metallic glasses high strength, but the extent to which they affect other macroscopic deformation properties is uncertain. For example, the nature of the plastic-yield criterion is a poi...

a semi-micromechanical multilaminate model is introduced here to predict the mechanical behavior of soils. this model is like a bridge between micro and macro scale upon the satisfaction of minimum potential energy level during any applied stress/strain increments. the concept of this model is based on a certain number of sampling planes which constitute the elastic-plastic behavior of the soil...

This study explores the plastic deformability of highly density-fluctuated states due to the different thermal quenching process of the binary amorphous metals, Zr67Cu33, with embedded nanocrystals, Zr2Cu. To know the effect of local structural fluctuation, we prepare 5 computational models with Zr2Cu-nanocrystals that undergo rapid heat up and cool down. The region of nanocrystals is correspon...