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

Abstract

This paper presents an experimental and analytical study on pressure pulse propagation phenomena in a plastically deforming pipe filled with water. The simple and well-defined experiments have been performed in order to provide the fundamental data to verify a two-dimensional fluid-structure interaction code. The experimental facility consists of a test pipe and a pulse gun filled with water at room temperature. The pressure pulse was generated in the pulse gun by low velocity SK explosive, high velocity pentolite or a low energy detonator. Experiments have been performed on 3 m long, 16 cm OD and 0.287 cm thick stainless steel-316 pipe both with and without elbow section. Transient pressure, transient strain and plastic deformation are measured when the pressure pulse propagates along the test pipe which is jointed rigidly to the pulse gun. On entering the test pipe, the pulse attenuates rapidly to the yield pressure of the pipe (14 MPa) in about 40 cm. Large plastic deformation occurs over wider range in low velocity explosive experiments than high velocity explosive experiments. Peak pressure reduces in the elbow section more in the high velocity explosive experiments than the low velocity explosive experiments. The experimental results have been analyzed by using a two-dimensional code. The comparison between experiment and prediction for the pressure pulse propagation behavior shows fairly good results. However, the strains are 30–100% over-estimated by the code. This discrepancy is attributable to the influence of the strain rate on stress and the limitation of the calculational model for simulating the detailed structure of the test facility.