Linear analysis of fluid-filled membrane structures using generalised modes

A frequency domain model is developed for the analysis of the fluid-structure interaction of surface gravity waves with a fluid-filled membrane. The membrane structure shape under static load conditions is first calculated using a non-linear quasi-static finite element method. Generalised modes are then used to couple the effect of the external fluid and incident waves with the response of the membrane structure and the internal fluid. The system is then solved in the frequency domain. The model builds on existing theory where possible, while the use of generalised modes allows different mode types to be used depending on what is appropriate for the analysis. Results computed for a bottom-mounted fluid-filled membrane are compared with previous numerical and experimental results.