Self-Excited Vibrations Occurring in Collapsible Tubes : Analysis by Lumped Parameter Model

Abstract

In this paper, self-excited vibrations occurring in collapsible tubes are investigated on the basis of a lumped parameter model. The instability condition is theoretically derived and the unstable region is indicated, which almost coincides with that of the simplified model in the previous paper. It is shown that the collapsible tube system consists of two modes corresponding to the characteristic roots of the system, and that the higher frequency mode can be unstable but the lower frequency mode is always stable. The global behavior of the collapsible tube is numerically investigated.