Abstract
This paper investigates the parametric instability in a straight bellows subjected to unsteady oscillating internal fluid pressure by the earthquake experimentally. It is observed that the lateral vibration in the bellows increases rapidly when the dynamic pressure in the piping system due to the seismic excitation in the bellows becomes larger. Then the parametric instability is caused in the bellows. The critical dynamic pressure for exciting the parametric instability obtained by experiment is compared with simulation results obtained by numerical simulation.
