Plastic Pipes Conference Association # 2006 Washington DC
Haager, Pinter, Lang
It is well known that resistance against slow crack growth is important for the lifetime of pressurized polyethylene (PE) pipes. Thus several methods have been proposed to evaluate the long-term performance of PE using fracture mechanics. It is generally believed that this leads to results more quickly compared to internal pressure tests. In the presented research work a method is introduced which uses fatigue loading of cracked round bar (CRB) specimens, to characterize crack growth resistance. It is shown that in the brittle failure regime typical fibrillated fracture surfaces where present and that the failure time gives an indication on the slow crack growth performance of PE pipe materials. The method was applied to several commercially available PE pipe materials and a ranking was established. In addition some crack growth tests were performed at 80 °C; it turned out that although some materials behave almost similar at room temperature, there is a considerable difference at 80 °C.
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