Recently, a dislocation free deformation mechanism was proposed by Kiritani et al., based on a series of experiments where thin foils of fcc metals were deformed at very high strain rates. In the experimental study, they observed a large density of stacking fault tetrahedra, but very low dislocation densities in the foils after deformation. This was interpreted as evidence for a new dislocation...

In continuum mechanics inelastic deformation is attributed to the aggregate effect of irreversible gliding of atoms along well defined planes whose number and orientation depends on the crystallographic structure of the material. Such a gliding plane and its pertaining gliding direction are termed “slip system”. It is activated by mechanical stresses expressed in terms of the resolved shear str...

Hierarchical composite materials design in biological exoskeletons achieves penetration resistance through a variety of energy-dissipating mechanisms while simultaneously balancing the need for damage localization to avoid compromising the mechanical integrity of the entire structure and to maintain multi-hit capability. Here, we show that the shell of the bivalve Placuna placenta (~99 wt% calc...

A hypothesis is formulated and substantiated that quasi-static deformation in an amorphous metal alloy a complex relaxation multi-stage process, which hierarchical sequence of interrelated structural transitions the first order ordered time. These nonequilibrium processes sequentially proceed at different scale space-time levels, starting from lowest level --- cluster atoms coordination sphere ...

In this paper the effects of the strain rate on the inelastic behavior and the self-heating under load conditions are presented for polymeric materials, such as polymethyl methacrylate (PMMA), polycarbonate (PC), and polyamide (PA66). By a torsion test, it was established that the shear yield stress behavior of PMMA, PC, and PA66 is well-described by the Ree-Eyring theory in the range of the co...

This work exploits the high accuracy of mixed 3?field u/e/p formulation to address materially non-linear inelastic problems including isochoric deformations. Motivated by strain-driven format several constitutive equations used in FEA, u/s/p is reinterpreted, selecting deviatoric strains as primary variables, together with displacements and pressure field. The complemented suitable for Solid Fl...