Abstract :
In this work, a new 3-dimensional viscoplastic
model based on a previous plasticity theory is
presented. The proposed constitutive model anticipates
the contribution of the main features of plastic
behavior, such as yielding, rate effect, isotropic and
kinematic hardening, through a new approximation of
the constitutive equation with a viscoplastic term, as
well as a new consideration of the functional form of
the rate of plastic deformation. A high accuracy
simulation of shear experimental data at various rates
and temperatures for a variety of materials, as well as
the sign inversion of normal stress has been postulated
