Ankündigung eines Vortrages von
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Abstract:
From the viewpoint of modern mechanics and physics of solids, internal
structure of a material under deformation exerts a predominating influence on
the elastic-plastic behaviour at the meso-scale level. Experimental and
theoretical investigations indicate a key role of internal heterogeneity for the
development of stress concentration and plastic strain localisation under
loading.
The majority of the experimental methods of in situ investigations of
plastically deformed materials are mostly reduced to surface observations. In
this connection, a numerical simulation including consideration of internal
structure in an explicit form shows promise for studying plastic deformation
patterns in the bulk of heterogeneous media.
In our work we investigate numerically elasto-plastic behaviour of heterogeneous
media under dynamic loading. Assuming that a medium under plastic deformation
retains its continuity at the meso and macro scale levels, we apply mathematical
tools and a numerical method of continuum mechanics. An internal structure is
introduced by prescribing appropriate physical properties to computational cells
corresponding to different structural elements.
A relaxation approach is applied to describe elasto-plastic behaviour, according
to which stresses increase in proportional to total strain rates and relax as
plastic deformation develops. A special yield criterion is developed to take
into account surface and interface effects. The results of two- and
three-dimensional calculations of dynamic deformation, including tension,
compression and shock wave loading, are presented and discussed.