145 Effect of Initial Geometric Misalignments of the Circular Notched Bar Specimen on the Fatigue Crack Growth Behavior

In this study, the effect of various misalignments of the circular notched bar(CNB) specimens on the fatigue crack propagation behavior of pipe grade polyethylene is investigated by three dimensional numerical analyses. The effect of the asymmetric crack growth of the misaligned CNB specimens on the lifetime to failure is also addressed. Combined misalignments (concentric misalignments + angular misalignments) of the CNB specimen are considered using finite element analysis. In general, as the misalignments increase, the asymmetric crack growth is accelerated so that the time to reach the critical SIF decreases. Therefore, it can be understood that the lifetime to failure of CNB specimens can vary noticeably once the CNB specimen is misaligned initially. Considering results from this study, the fatigue crack growth behavior including the estimation of the lifetime of CNB specimens should be addressed by considering the misalignment effects.