Response of Submerged Structures by the Finite Element-Cum-Boundary Element Method

A double asymptotic approximation based finite element-cum-boundary element approach for fluid-structure interaction problems is being proposed. In particular a staggered solution scheme has been applied to the analysis of various coupled fluid-structure systems. A stabilization scheme by reformulation, proposed by DeRuntz et al. was employed to circumvent the instability problem. In addition, the singularity in the excitation term was eliminated through a variable transformation as suggested by Everstine. Another feature of the present work is its incorporation of the hybrid strain based lower order triangular shell finite element developed by To and Liu. The eigenvalue solution exhibits high convergence rate for the particular shell finite element employed. The responses calculated exhibit the effectiveness of the proposed approach with application of the aforementioned shell finite element in dealing with three dimensional fluid-structure interaction problems. The reduction in problem size that this approach affords allows these complex interaction problems to be dealt with in a desktop engineering workstation environment, as opposed to the mainframe and supercomputer arenas where they have been implemented in the past.