ON THE APPLICABILITY OF LINEAR ELASTIC FRACTURE-MECHANICS TO ENVIRONMENTAL-STRESS CRACKING OF LOW-DENSITY POLYETHYLENE

The primary aim of this work was to re-examine the range of applicability of linear elastic fracture mechanics (LEFM) to environmental stress cracking of low-density polyethylene. By use of a number of specimen types and a range of specimen dimensions and loads it is shown that the K//1-c relationship is unique only at low K//1s. The material studied showed a region of constant crack velocity which was not caused by plasticity effects or the failure of LEFM. However, crack arrest, which occurred at high K//1s or loads, was shown to be caused by ductile yielding causing the crack to blunt.