Applications of the static condensation technique to nonlinear structural analysis of floating offshore structures

Abstract

A cost effective finite element (FE) procedure is proposed for analysis of load-carrying structures with nonlinear contact and frictional behaviors between large floating offshore structures. The key of the procedure is to use the static condensation technique developed from the Guyan model reduction method. The time for computing contact and friction forces on contact interface areas can be dramatically reduced compared to nonlinear analysis with a full FE model. Two representative applications to offshore projects are presented. One is a problem with nonlinear contact of independent tank support in FLNG hull structures and the second is a seafastening system used during offshore dry transportation. The reliability and computing efficiency of the proposed analysis procedure are investigated. It is conclusively confirmed that the proposed procedure is practical for application to actual design of offshore projects.