Propagation d'ondes le long de réseaux de tuyauteries

Abstract
In order to understand the shocks mechanisms propagation, the CERT / ONERA / DERMES is interested in structural waves propagation in piping system network. The free vibration of a cylindrical thin-walled shell can be described by the Donnell-Mushtari theory, added to Flügge formulation. The resolution of this equations system leads to a 6 order equation in [MATH] (motion frequency). In this way, we obtain the axial, radial and circumferential propagation modes eigenfrequencies. However, due to the hypothesis of long pipe assumption, only the radial mode is taken into account. The theoretical approach is completed by an experimental study. Thus, the waves propagation along straight pipes and in complex system (in 3-D) including some representative discontinuities of system network (single 45° bend, single 90° bend, T-Joint, curved-pipe...) is analyzed. The aim is to quantify the amplitude attenuation of a radial propagation mode of the shell through these kind of discontinuities. The study is carried out in order to realize a numerical simulation software of vibrational waves propagation along piping system network. This study is financed by a natural gas transmission company : Gaz du Sud-Ouest.