A fracture mechanics approach for the prediction of the failure time of polybutene pipes

In this work two grades of Isotactic polybutene-1 with a different degree of isotacticity have been investigated; fracture tests have been performed at various temperatures and testing speeds on DCB and SENB samples. Optical methods have been used to record crack advancement. Results of the tests have been interpreted using the fracture mechanics framework; a time–temperature superposition scheme has been adopted to describe crack propagation behaviour over several decades of time-scale. An analytical model has been applied to predict the lifetime of pressurised pipes from experimental fracture data. There is good agreement between model predictions and experimental data obtained from full-scale tests on real pipes.