The installation phase for a topside module suggested can be divided into 9 stages, which include start, pre-lifting, lifting, lifted, rotating, positioning, lowering, mating, and end of installation. The transfer of the topside module from a transport barge to a crane vessel takes place in the firs...
The installation phase for a topside module suggested can be divided into 9 stages, which include start, pre-lifting, lifting, lifted, rotating, positioning, lowering, mating, and end of installation. The transfer of the topside module from a transport barge to a crane vessel takes place in the first three stages, from start to lifting, while the transfer of the module onto a floating spar hull occurs in the last three stages, from lowering to the end. The coupled multi-body motions are calculated in both calm water and in irregular waves with significant wave height (1.52m), with suggested force equilibrium diagrams. The effects of the hydrodynamic interactions between the crane vessel and barge during the lifting stage have been considered. The internal forces caused by the load transfer and ballasting are derived for the lifting phases. The results of these internal forces for the calm water condition are compared with those in the irregular sea condition. Although the effect of pitch motion on the relative vertical motion between the deck of the floating structure and the topside module is significant in the lifting phases, the internal force induced pitch motion is too small to show its influence. However, the effect of the internal force on the wave-induced heave responses in the lifting phases is noticeable in the irregular sea condition because the transfer mass-induced draught changes in the floating structure are observed to have higher amplitudes than the external force induced responses.
The installation phase for a topside module suggested can be divided into 9 stages, which include start, pre-lifting, lifting, lifted, rotating, positioning, lowering, mating, and end of installation. The transfer of the topside module from a transport barge to a crane vessel takes place in the first three stages, from start to lifting, while the transfer of the module onto a floating spar hull occurs in the last three stages, from lowering to the end. The coupled multi-body motions are calculated in both calm water and in irregular waves with significant wave height (1.52m), with suggested force equilibrium diagrams. The effects of the hydrodynamic interactions between the crane vessel and barge during the lifting stage have been considered. The internal forces caused by the load transfer and ballasting are derived for the lifting phases. The results of these internal forces for the calm water condition are compared with those in the irregular sea condition. Although the effect of pitch motion on the relative vertical motion between the deck of the floating structure and the topside module is significant in the lifting phases, the internal force induced pitch motion is too small to show its influence. However, the effect of the internal force on the wave-induced heave responses in the lifting phases is noticeable in the irregular sea condition because the transfer mass-induced draught changes in the floating structure are observed to have higher amplitudes than the external force induced responses.
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제안 방법
In the present investigation however, lateral motion is assumed to be small and is thus not considered because the floating structure is assumed to be constrained by mooring lines. During the lifting, crane induced motions are most interesting part of this research so the pitch and heave motions of crane vessel and the heave motion of the barge are examined in time domain results. The topside module is hooked with sling through the crane and this sling is assumed as rigid i.
The installation phase is divided into 9 stages: start, prelifting, lifting, lifted, rotating, positioning, lowering, mating and end of installation. However after the lifting stage is over, rotating to the spar at -90 deg and mating stages are not included in the present study.
대상 데이터
Prior to the time-domain dynamic lift analysis, a multi- body diffraction analysis in the frequency domain was carried out for the crane vessel together with barge S44. The crane vessel with 1172 panels, and barge S44 with 810 panels as shown in Fig. 2.
참고문헌 (5)
Chan, H.S. (2003). "Global Wave Loads on Intact and Damaged Ro-Ro Ships in Regular Oblique Waves", Marine Structures 2003, Vol 16, No 4, 323-344.
Choo, Y.S., Lim, C.K., and Bok, S.H. (1993). A Knowledgebased Approach to Design for Heavy Lift, Offshore 93, 3rd Intl Conf, Installation of Major Offshore Structures and Equipment, Feb., 1993, London, UK, ppr 8, pp 83-97.
Cveticanin L. (1995), "Dynamic Behavior of the Lifting Crane Mechanism", Mechanics Machine Theory, Vol 30, No 1, 1995, pp 141-151.
Oortmerssen, G.van and Pinkster, J.A. (1976). "Computation of First and Second Order Wave Forces on Bodies Oscillation in Regular Waves", Proceedings 2nd International Conference Ship Hydrodynamics, Berkeley, 1976.
Schellin, T.E., Jiang, T. and Ostergaard, C. (1993). "Crane Ship Response to Wave Groups", Journal of Ship Research, Vol 37, No 3, Sept. 1993, pp 225-238.
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