Dynamic Performance Research On Rigid-flexible Coupling Crane Vessel With Super Lifting Capacity

Deep-water heavy lift crane, which has been widely used in construction, salvage operations and other offshore-engineering, is one kind of offshore servicing systems with super lifting capacity and high working efficiency. As a consequence of its high center of gravity, together with more severe working environment as the operation water depth gains dramatically, the study on the dynamic performance of heavy lift crane has been a hotspot in the field of offshore engineering. The rigid-flexible coupling model of one heavy lift crane is established and its dynamic responses under different conditions are analyzed in this paper:(1) The Lagrange's dynamical equation is the theoretical foundation of this paper.The rigid-flexible coupling model of the whole lift system, together with its external forces are derived according to the lift crane's actual characteristics of movement. In addition with the purpose of this paper, the model and its external forces are simplified properly;(2) The dynamic characteristics of the A-Frame and boom are of great importance for the whole lift system. The modal analysis has been carried out to acquire their natural frequencies and modes of vibration. The results makes it clear that taking the A-Frame and boom as flexible elements into the whole lift system's dynamic analysis is extremely important;(3) AQWA Hydrodynamic Analysis Software has been applied to calculate the hydrodynamic coefficients of heavy lift crane-"HYSY201". And various other scholars, the added mass coefficients of relevant wave frequency have been used in the dynamic analysis of the whole lift system;(4) ANSYS has been used to assemble of the rigid-flexible coupling lift system and conduct the dynamic performance analysis under different working conditions. The results show that the sensitivities of the lift system's each DOF to wave incoming direction,wave frequency, wire rope length and so on are entirely distinct.It should draw the intention that in order to make the hoisting process work smoothly and efficiently, the amplitude of each DOF of the whole lift system should be monitored and controlled constantly according to results of this dynamic performance analysis.