The vibration of a corrugated carbon fibre pressure vessel under external hydrostatic pressure

The paper presents a theoretical and an experimental investigation into the vibration of a corrugated carbon fibre cylinder in air and under external water pressure. The theoretical investigation was via the finite element me thod, where both the shell and the surrounding water were modelled with axi symmetric finite elements. In the case of the shell, the element allowed fo r orthotropicity and in the case of the water, the element was a solid elem ent with an isoparametric cross-section. Good agreement was found between e xperiment and theory for both the vibration in air and the vibration under external water pressure. The results showed that as the external water pres sure was increased, the resonant frequencies decreased. This appeared to ag ree with previous findings that a form of dynamic buckling could occur when the vibration eigenmode was the same form as the buckling eigenmode, in re sponse to a periodic excitation force.