Life prediction of multi-pit-crack interaction in pressure vessel

Abstract

During the service of pressure vessel, there are many kinds of structural damage. The main defect is pitting caused by corrosion of loaded materials, cracks are formed because of stress concentration in the pit position, and crack propagation leads to crack leakage. As an important parameter to characterize cracks, fatigue life is widely used in engineering to judge the safety and reliability of mechanical structures. In this paper, based on the two-parameter pit-crack model, the fatigue life of pressure vessel with multiple pits-cracks is discussed by using ANSYS finite element analysis software. The results show that the fatigue life of pressure vessels decreases with the existence of multiple pits and cracks, but with the increase of pit-crack spacing, the effect decreases gradually until it returns to a stable state. The effect of pit parameters and the ratio of crack length to depth on fatigue life has obvious interval effect. This paper can be used as a reference for failure assessment of multi-pit-crack pressure vessels.

Reliability assessment of ship hull girders considering pitting corrosion and crack

“…Song et al [6] studied pit-to-crack transition under simultaneous electrochemical and mechanical effects. Zijie et al [7] studied the fatigue life of pressure vessels with multiple pits and cracks.…”