EVALUATION OF THE EFFECT OF A WATER HAMMER ON THE FAILURE OF A CORRODED WATER PIPELINE

摘要

A numerical model has been created to simulate the propagation of pressure waves in water networks. The model takes into account the structure of the water network and the pressure loss. When several valves are closed simultaneously, pressures can exceed the admissible pressure and cause failure. In this case, the severity of a defect such as a corrosion crater (pit) has been estimated by computing a safety factor for the stress distribution at the defect tip. To investigate the defect geometry effects, semi-spherical and semi-elliptical defects are assumed to exist up to one half thickness of the pipe wall. The results have been input into the Structural Integrity Assessment Procedure (S1NTAP) Failure Diagram Assessment (FAD) to obtain the safety factor value. Conventionally, it is considered that the failure hazard exists if this safety factor is less than two.