ジャッキ・アップ・リグの強度特性に及ぼす浅海,波形,相対速度および相対加速度の影響

抄録

The accuracy of structural strength and forced vibration analysis depends on the accuracy of wave force estimation. The wave force shows non-linearity by the effect of shallow water, wave profile, relative velocity and acceleration between leg and water particles by vibration. In the previous paper , the considerations of these non-linear effects are omitted but the jack-up rigs mainly operate at relatively shallow water less than 100m and the wave forces on legs between crest and trough of wave profile show the remarkable non-linearity. Additionally, the relative velocity and acceleration also cause the non-linearity for wave exciting force. In this paper, the structural analysis methods how to consider these non-linear effects are presented and their effects to the structural characteristics are studied and the permissible limits not to be necessary to consider these effects are discussed from the practical design point of view.