THE RELATIONSHIP BETWEEN SLOW CRACK-PROPAGATION AND TENSILE CREEP-BEHAVIOR IN POLYETHYLENE

The creep characteristics of drawn samples of a number of grades of po lyethylene have been studied over a range of applied stresses and stra ins. In each case, the data allowed a unique and reproducible true str ess:strain:strain rate surface to be determined. These data have been used in a new computer-based model for the mechanism of craze growth d uring the initiation of slow crack propagation. Using the model it has been possible to define the contribution the creep of the drawn mater ial makes to craze growth and ultimately to the failure of the craze.