AbstractThe paper reviews the various classical failure theories essentially developed for metals and then seeks to show that the same theories with slight modifications could be used to describe failure of polymeric materials. These modifications consist in the consideration of the effect of rate loading on failure behavior. In addition, the paper reports experimental results on failure of two polymeric materials under uniaxial tension loading and several biaxial stress fields corresponding to pure internal pressure, internal pressure combined with tension and torque loadings and several biaxial stress fields corresponding to pure internal pressure, internal pressure cobined with tension and torque loadings. The failure behavior under various stress fields has been studied for maximum principal rates ranging from 0.05 to 60 psi. sec. The predictions based on various criteria of faliure, which considers the effect of rate of loading, are compared with the experimental results. Finally, it is shown that failure behavior under triaxial stress fields can be reasonably predicted from biaxial stress failure data.