Computer estimation of plastic strain localization and failure for large strain rates using viscoplasticity

The problem of modelling extreme dynamic events for metallic materials including strain rates over 10

7

s

-1

and temperatures reaching melting point is still vivid in theoretical, applied and computational mechanics. Such thermomechanical processes are highly influenced by elasto-viscoplastic wave effects (their propagation and interaction) and varying initial anisotropy caused by existing defects in metals structure like microcracks, microvoids, mobile and immobile dislocations densities being together a cause of overall induced anisotropy during deformation (from the point of view of meso-macro continuum mechanics approach). It should be emphasised, that the most reliable way for estimation of such processes needs nowadays a complex phenomenological models due to limitations of current experimental techniques (it is still not possible to measure the evolution of crucial quantities e.g. temperature for extreme dynamic processes) and computational capabilities.

Within this document we consider recent achievements of Perzyna's type viscoplasticity theory for metallic materials accounting for anisotropic description of damage suitable for modelling plastic strain localization and failure for large strain rates.