Configuration Optimization Based On Reducing The Connector Load Of VLFS

The connectors linking together the multiple modules of a Very Large Floating Structure(VLFS)are the most important and yet the weakest part of the VLFS system.The wave forces acting on a multiple moduled VLFS connected with hinge-like connectors can lead to excessive loads in the connectors.Numerical simulation results have shown that in medium to high sea states,the loads in hinge-like connectors can reach a magnitude of over 10000 tones,which is a huge challenge to the design of the connectors as well as the hull structure of the VLFS on which the connectors are mounted.Previous studies have found that the main reason for such an excessively high load in hinge-like connectors is the horizontal bending moment in the VLFS caused by the wave force,and the longer the VLFS the higher the connector loads.An effort has been made in this paper on the reduction of the connector loads by optimizing the geometry of the wetted hull of the VLFS so that the structural bending moment is reduced,which in turn results in the reduction of the connector loads.The main contents of the paper are as follows: firstly the basic concepts of the VLFS,the connection modes of the modules and the challenges facing the connector design are introduced.Secondly on the basis maintaining the main dimensions of the VLFS,a number of modified configurations of the VLFS are designed in an attempt to alter the hydrodynamic loads on the VLFS hulls so that structural loads in the connectors can be reduced;Finally,based on the three dimensional potential flow theory,frequency domain and time domain analyses are performed to calculate the hydrodynamic and connector loads of various box type and semi-submersible type VLFS configurations,and by comparing the optimization efficiency,the optimal VLFS configurations,in the sense of lower connector loads,are obtained.The main results of this study are: propose the idea and implementation method to reduce the connector load caused by the configuration optimization of the part below the waterline of the floating body to reduce the horizontal bending moment of the single module and multi-module structure;Based on this,a series of optimization designs for the box-type and semi-submersible VLFS were carried out and their structural horizontal bending moments and connector loads were calculated.The results show that the connector load can be significantly reduced through configuration optimization.It can provide a useful reference for VLFS configuration and connector design.