An Arctic Spar is characterized by its conical shape near the waterline. In this case, the nonlinear effects from its irregular hull shape would be significant if there is either a large amplitude floater motion or steep wave conditions. Therefore, in this paper, the nonlinear effects of an Arctic Spar are numerically investigated by introducing a weakly nonlinear time-domain model that considers the time dependent hydrostatic restoring stiffness and Froude-Krylov forces. Through numerical simulations under multiple regular and irregular wave conditions, the nonlinear behavior of the Arctic Spar is clearly observed, but it is not shown in the linear analysis. In particular, it is found that the nonlinear Froude-Krylov force plays an important role when the wave frequency is close to the heave natural frequency. In addition, the nonlinear hydrostatic restoring stiffness causes the structure's unstable motion at a half of heave natural period.

北极晶石的特点是在水线附近呈圆锥形。在这种情况下，如果存在大幅度的浮动运动或陡波条件，则来自其不规则船体形状的非线性影响将非常显着。因此，在本文中，通过引入弱非线性时域模型对北极晶石的非线性效应进行了数值研究，该模型考虑了与时间有关的静液压恢复刚度和Froude-Krylov力。通过在多个规则波和不规则波条件下的数值模拟，可以清楚地观察到北极晶石的非线性行为，但在线性分析中未显示。特别地，发现当波频率接近升沉固有频率时，非线性弗洛德-克雷洛夫力起着重要作用。此外，