Numerical Simulation of Submerged Payload Coupled with Crane Barge in Waves

Abstract

`Offshore lifting and installation? is an integral part of all offshore activities and with the growing interests of mankind towards offshore with more innovative ideas, the safe operation of offshore crane vessel is gradually becoming challenging than ever. Because, heavy duty installations of unconventional structure, even at relatively calm sea, can generate unexpected and excessive motions of the structure underwater, which can cause the collision between the load and the ship or other objects and thus cause loss of valuable asset and time. This thesis focuses on providing an insight of the entire process of such offshore installation via the evaluation of hydrodynamic performances of a fixed crane barge and its submerged moving payload in water waves. The main attention is given towards the comprehensive analysis of the dynamic behavior of the payload and the fully nonlinear three dimensional time domain approach is used to solve the problem as this method is capable of handling the full nonlinearity compared to the frequency domain approach. The results of the analysis can be used for safety considerations during the offshore installation process and would be beneficial to the researcher working on designing active damping devices to extend the operating range of crane ships by means of controlling the motion of the submerged payload.