Fracture mechanics characterisation of effects of stabilisers on creep crack growth in polyethylene pipes

The failure behaviour of several polytheylene (PE) formulations has been ch aracterised using linear elastic fracture mechanics (LEFM), creep crack gro wth (CCG) tests, and internal pressure testing. In total, six PE formulatio ns (two polymer types with three stabiliser systems) were investigated. Whi le no influence of stabiliser type was found in either type of polymer at h igh crack speeds, significant effects of the added stabiliser type and conc entration were found for very low CCG rates. The experimental data also ind icate good agreement between the rest results of CCG experiments and the pr essurised pipe tests (i.e. identical material ranking in both tests). This corroborates the hypothesis that the brittle or quasi-brittle failure of pr essurised pipes can be predicted using a LEFM approach and that CCG tests m ay be a useful experimental screening tool to evaluate stabiliser effective ness.