Experiment and analysis on pressure pulse propagation in a plastically deforming pipe

This paper presents the experimental and analytical study on the behavior of pressure pulse propagation travelling through a piping system. The simple, well-defined experiments have been performed to provide the fundamental data to verify a dynamic response computation code. Experimental facility consists of a test pipe and a pulse gun filled with water at room temperature. The pressure pulse has been generated by low velocity SK explosive, high velocity pentolite and low energy detonator. The SK explosive was composed mainly of potassium perchlorate and aluminum in flake and grain form. Experiments have been performed by using 3 m - long, 16 cm - outer diameter, 0.287 cm - thick stainless steel pipes both with and without 90 degree elbow section. The experimental results show that the pulse entering a test pipe attenuates rapidly to the yield pressure (about 14 MPa) of the pipe on about 40 cm of inlet section. The plastic deformation extends over wide range in low velocity explosive experiments than in high velocity pentolite ones. The peak pressure attenuates while passing thick-walled elbow particularly in high velocity pentolite experiment rather than in low velocity explosive one. The experimental results have been analyzed by a two-dimensional dynamic fluid-structure response code. The prediction of pressure pulses in test pipes are in fairly good agreement with the experimental results. The predictions of residual strains of the pipes are 30-100% larger than the results. Further investigation will be required to improve the predictions of residual strains. (orig.)