THE VARIABLE THRESHOLD ROD EXPERIMENT - A COMPARISON OF MEASURED AND COMPUTED DEFORMATIONS

A novel experiment has been developed to induce inhomogeneous deformat ions under simple extension boundary conditions. By appropriate prior cold working of stock material and fabrication of test specimens with tailored dimensions, the location of the deformation zones along the g age length of tensile specimens was controlled. By design, the deforma tions were chosen to concentrate either toward the harder or softer en ds of the specimens. The experiment provides a sensitive test to judge the ability of constitutive models to replicate the behavior of metal s undergoing inhomogeneous deformation. A comparison of experimental r esults with simulated response using an isotropic state variable model is presented.