Study on the Failure Assessment of Small Diameter Pipe With Circumferential Crack Under Monotonic and Cyclic Multi-Axial Loading

Abstract

Failure behaviors of small diameter pipe of austenitic stainless and carbon steels with circumferential crack under monotonic and cyclic multi-axial loading were observed and the criteria of failure under these conditions were investigated. For the failure under monotonic loadings, it was observed that the maximum load was attained when the net section von Mises equivalent stress almost reached to the flow stress of the material. For the cyclic loading, Pa/Pmax or Ta/Tmax seems to be a good parameter to estimate failure life irrespective of specimen thickness, initial crack size and loading pattern, especially for STPT410. Here, Pa and Ta are load and torque amplitude respectively, and Pmax and Tmax are the maximum load and torque under monotonic loading with the same loading pattern for cyclic loading.