Investigations of Dent Rerounding Behavior

A theoretical model was developed to describe the structural behavior of indented pipe under pressure. The model suggested that the transverse shape of the dent, which can be characterized by a single easily-measured parameter, significantly affects rerounding behavior. The model gave predictions for rerounding that were in good agreement with results of tests. Tests also indicated that dent rerounding behavior is cycle-dependent. The model sets a groundwork for estimating the fatigue life of dented pipe subject to pressure cycles. The results apply primarily to plain dents, but might be adapted to those that contain collateral mechanical damage.