The dynamic response of the telescopic gangway strongly links to the relative motion which is significant when the gangway vessel works along with another floating unit in proximity. The failure might cause operational downtime or even personnel casualty. In this paper, gangway motions, including extension, retraction, rotations, and relative motions, are studied numerically in the time domain and compared to experimental measurements. The hydrodynamic interaction of the multi-body system is analyzed by 3D diffraction and radiation computation in the frequency domain. The nonlinear roll damping is calibrated and validated in both free decay and regular waves. Two uni-directional scenarios of primary irregular waves and one bi-directional scenario of both primary and secondary irregular waves are taken into account in the study. Remarkable vertical motion up to 10 m between gangway departure and landing points are observed even if the significant wave height is only 3.25 m. Extreme value analysis shows the gangway inclination can be as high as 17° which exceeds the maximum acceptance so that enhanced slip resistance feature must be added on the gangway. The different patterns of gangway motion trajectory in the vertical plane are also illustrated to corroborate the conclusion.

伸缩舷梯的动态响应与相对运动密切相关，当舷梯船与附近的另一个漂浮装置一起工作时，该相对运动非常重要。该故障可能导致操作停机，甚至造成人员伤亡。在本文中，在时域中对舷梯运动（包括伸展，缩回，旋转和相对运动）进行了数值研究，并与实验测量结果进行了比较。通过在频域中的3D衍射和辐射计算来分析多体系统的流体动力相互作用。非线性侧倾阻尼在自由衰减和规则波中都经过校准和验证。在研究中考虑了两个主要的不规则波的单向情景和一个主要的和次要不规则波的双向情景。即使有效波高仅为3.25 m，也可在舷梯离开和着陆点之间观察到高达10 m的显着垂直运动。极值分析显示，舷梯的倾斜度可能高达17°，超过了最大允许范围，因此必须在舷梯上增加防滑性能。垂直平面上的舷梯运动轨迹的不同模式也得到了说明，以证实这一结论。