Analysis of pipe wall vibration for leak detection in fluid-filled piping systems

This paper is concerned with the low-frequency behaviour of the pipe wall in response to the axisymmetric (n=0) motion associated with both the fluid-dominated (s=1) and shell-dominated (s=2) waves in fluid-filled piping systems. The strength of the coupling between these wave motions is governed by the dimensions of the pipe and the physical properties of the coupled system. For most practical pipework systems, they are strongly coupled. In this circumstance the expected ratio of the pipe wall displacements associated with these two waves are investigated theoretically. The paper then proceeds to examine the pipe wall motions in terms of the internal pressure. Numerical results show the relative insensitivity of the pipe wall displacements to the shell-dominated (s=2) wave for heavy fluid loading, as is the case for plastic pipes, and thus the pipe wall motions can be evaluated by monitoring the internal pressure resulting from the fluid-dominated (s=1) wave.