TRANSIENT FLUID-STRUCTURE INTERACTION IN NAVAL APPLICATIONS USING THERETARDED POTENTIAL METHOD

Submerged structures subjected to underwater shock remain a difficult and costly problem to analyze. In this work, the retarded potential (R P) method, which is a boundary element technique, is employed to discr etize the fluid domain. The retarded potential program RPF is coupled to the ABAQUS non-linear finite element program to form ABAQUS/RPF. Th e Figueiredo method is used to convert the standard RP differential-de lay equations for the fluid to simply delay equations, which are inher ently more stable. ABAQUS/RPF is applied to both a rigid and elastic s phere. The Figueiredo approach is seen to extend significantly the sta bility range of the standard RP by a factor of approximately 10-20. In tegration of the constant-pressure RP fluid element is shown to be ver y important to achieve this level of accuracy. Efforts to improve the Figueiredo approach using higher-order finite difference operators app ear to have no effect on accuracy or stability. Stability of the coupl ed system is achieved by simply not extrapolating the structural accel erations. (C) 1998 published by Elsevier Science Ltd. All rights reser ved.