Florian Arbeiter, Gerald Pinter, Andreas Frank
Papers # 2012 Barcelona
Failure of polymer pipes due to slow crack growth (SCG) is a well-known problem throughout the industry. During the last decades various authors provided vital information for characterizing this type of failure in polyethylene (PE) pipes. For industrial pipe applications however polypropylene (PP) is also a widely used material. Due to its very ductile behaviour it was not possible to characterize PP pipe grades using linear elastic fracture mechanics (LEFM) in feasible time frames so far. In this work SCG behaviour of three different types of possible PP pipe grades is characterized using the recently standardized cyclic Cracked -Round -Bar (CRB) test and fracture mechanic tests under static and cyclic loads with Compact-Tension (CT) and Grooved Compact-Tension (GCT) specimen, respectively. The CRB-tests were used to determine the cycles-to-failure (Nf) for the quasi-brittle failure mode. In consequence of its constraint at the notch root, this test promises short testing times. CRB and GCT specimen were utilized to characterize actual crack-growth kinetics of the materials.