%0 Journal Article
%A Abed, Farid H.
%A Voyiadjis, George
%D 2007
%I Begell House
%N 3-4
%P 325-349
%R 10.1615/IntJMultCompEng.v5.i3-4.120
%T Adiabatic Shear Band Localizations in BCC Metals at High Strain Rates and Various Initial Temperatures
%U http://dl.begellhouse.com/journals/61fd1b191cf7e96f,3cf3b25417fa966d,3e38f0f0032f6c08.html
%V 5
%X In general, metal structures display a strong rate and temperature dependence when deformed nonuniformly into the inelastic range. This effect has important implications for an increasing number of applications in structural and engineering mechanics. The mechanical behavior of these applications cannot be characterized by classical (rate-independent) continuum theories because they incorporate no material length scales. It is therefore necessary to develop a rate-dependent (viscoplasticity) continuum theory bridging the gap between the classical continuum theories and the microstructure simulations. A finite strain hypoelastoviscoplastic framework is developed for body-centered cubic metals using the corotational formulation approach. Material length scales are implicitly introduced into the governing equations through material rate dependency (viscosity). An implicit objective stress update, which is an efficient algorithm for the type of nonlinear problems considered here, is employed. The effectiveness of the present approach is tested by studying strain localizations in a simple tensile plane strain problem and in a cylindrical hat-shaped sample over a wide range of initial temperatures and strain rates. The finite element simulations of material instability problems converge to meaningful results on further refinement of the finite element mesh. Comparisons of the simulation results of adiabatic shear localizations are also made, with experimental results conducted by different authors. Results indicate an excellent performance of the present framework in describing the strain localization problem for niobium, vanadium, and tantalum.
%8 2007-10-22