Prediction of Fatigue Crack Growth in Part-through Cracked Pipes Using Exponential Model and Gamma Model

A pipe installation experiences fluctuating loading condition. It may also experience occasional high amplitude vibration (Seismic Vibration). The monitoring and modelling of fatigue crack growth becomes more significant if the pipes carry hazardous fluids. However there is no any model available for fatigue crack growth for pipes. The primary objective of the present investigation is to develop a fatigue crack growth model for part-through cracked pipes. The pipes under investigation were of TP316L grade stainless steel. The four point bend test was conducted on pre-cracked specimen (notch angle 45° at the centre) using Instron 8800 machine. All the tests were conducted in air and at room temperature. In the present investigation an attempt has been made to develop a fatigue life prediction methodology by using an Exponential Model and a Gamma Model for part-through cracked pipes. The predicted results are compared with experimental crack growth data. It has been observed that the results obtained from the two models are in good agreement with experimental data