Wave Load And Structural Response Analysis Of Floating Bodies With Multiple Buoys Offshore

Multi-buoy floating platform is one of the new forms of offshore platforms in recent years,which are mainly located near offshore waters or islands.Their potential uses include offshore office,convention,exhibition,tourism,floating docks and aprons.However,there is no definite stipulation on the calculation load and structure analysis of platform of this structural type in the current domestic and international platform construction codes.Therefore,it is of practical engineering significance to carry out the analysis and research on wave load and structure response of this type of floating platform and to put forward corresponding calculation and evaluation methods.The main contents are as follows:Based on three-dimensional potential flow theory and Morrison formula,the response of special loads such as transverse separation force,longitudinal shear force,build-up acceleration,relative wave surface velocity of floating body measuring point and other conventional loads on the platform longitudinal section under different conditions are analyzed by using frequency-domain linear prediction method,and the method to determine the design load of this type of floating body is summarized and proposed;Based on air gap prediction theory,diffraction radiation theory and platform displacement offset balance,the mathematical model of floating body motion is established considering the effect of wind and flow as well as the coupling effect between the mooring system and the floating body.Considering the structural characteristics of multi-buoy floating body,the non-linear time-domain coupling analysis is carried out for the motion and wave surface rise of the floating body,and the extremes of air gap response and six-degree-of-freedom motion response of the floating body at each air gap monitoring point are obtained.The arrangement of air gap monitoring points suitable for this type of floating body is summarized and the motion response of multi-point moored floating body is verified to meet the requirements of specifications;Design wave method is applied to determine 20-year design wave corresponding to each load component of the floating body.Yield strength and deformation of the floating body is checked by finite element analysis method.Based on the analysis results,suggestions are made for the selection of overall structural strength and deformation analysis conditions of this type of floating body;Based on the Theory of flat plate slamming pressure and substructure method,through air gap response analysis,determine the dangerous points of the floating body susceptible to wave slamming,determine the extreme pressure and range of slamming action at the position of slamming action,load the pressure load on the local model for finite element analysis,extract the stress results of each part and compare with local slamming calibration and balance,check that the floating body is subject to wave slamming.Suggestions for evaluating local slamming strength of this type of floating body are put forward in summary for time-consuming structural safety.