A Theory of Rate-Dependent Plasticity
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
Pagination or Media Count:
The classical theory of rate-independent plasticity is modified by the addition of a rate variable to the yield surface. From considerations of physical metallurgy it is shown that the correct parameter to add is the effective plastic stRAIN RATE. Constitutive equations suitable for a rate- dependent elastic-plastic finite element structural analysis code are derived. For the simple loading case of uniaxial stress, an exact solution is derived which models many of the rate-dependent effects observed in material testing, e. g. the behavior of the stress-strain curves for constant rate tests change of rate tests, creeprelaxation above yield, etc.