Coupled boundary element method and finite element method for hydroelastic analysis of floating plate

In this study, a numerical procedure has been proposed to analyze the equation of motion of the elastic plate which is elastic in nature and having shallow draft (small thickness) with arbitrary geometry subjected to linear wave force at a fixed frequency. Investigation on the convergence of maximum deflection of the floating plate has been carried out. A hybrid model has been developed (coupling between FEM and BEM) which contains same nodes, maintaining the same order and basis function in both the methods. To develop the relationship between the displacement of the plate and the velocity potential under the plate, two equations have been derived. The first equation is derived from the equation of motion for the plate and is solved by finite element method (FEM) to extract the displacement of the floating structure. The second equation is from water wave theory which is based on boundary integral equation that relates the displacement of the floating plate and velocity potential using free-surface Green's function. To get the displacement of floating elastic plate and velocity potential both the equations are solved simultaneously. Results are presented for modified Green's function which has been derived and validated with the results of Meylan (2004). The performance of the developed model is examined by the convergence rate, simulation time. It is learnt that the model works well in finite depth whereas its performance in infinite depth lags by an average of 20% in simulation time than the results obtained by Meylan (2004).