# 2010 Vancouver
Different polyethylene pipe grades and lots were investigated with a fracture mechanics procedures under cyclic loads. The cyclic tests with Cracked Round Bars allowed a ranking of the different materials concerning crack resistance as a function of failure time as well as of crack initiation time within one week at room temperature. The ranking corresponded to the expectations based on the molecular and morphological properties of the materials. Moreover a lab internal reproduction series with tests on different machines and operators based on a first draft of a testing protocol proved the reproducibility of the results.