Comparison of the most harmful defects present in a steel pipe that can cause fatigue failure

Abstract

Abstract Steel pipes used for conveying pressurized fluids are often defective due to manufacturing error, improper handling or construction materials. These defects may be in the form of cracks which propagate until the mechanical structure is fractured, or in the form of dent which produce a local concentration of stress and thus weaken the structure. In this paper, we will present a numerical model for estimating the accumulation of damage that takes into account the effect of the loading history. This model will be used to evaluate the harmfulness of a dent on the one hand, of a semi-elliptical crack on the other hand. These defects wil be considered to be present in a metal tube subjected to internal pressures caused by the water hammer phenomenon. A parametric study will make it possible to conclude the most harmful defects among the defects studied.