Ice bending fracturing is a major failure mode for sea ice act on offshore wind turbines (OWTs) with icebreaker. The cohesive element method (CEM) is applied to simulate the bending fracturing and fragmentation accumulation of the level ice in the presented study. The elastoplastic linear softening constitutive model is used to consider the characteristics of S2 columnar ice, and the transversely isotropic Tsai- Wu failure criterion is adopted to predict the ice failure. The proposed interaction coupling model is implemented into the LS-DYNA finite element code. Then, the sea ice crack expansion, breaking, sliding, and accumulation are observed under different ice velocities. Meanwhile, the numerical results are validated against the ice force model test data. Furthermore, the structural motion responses of the OWT under sea ice loads are investigated, and influence of ice velocities is observed. The results show that the ice velocity has no significant effect on ice force and structural motion response. However, the fracture size are decreased with the increasing of ice velocities.
With the continuous exploration of wind energy resources (Zhao et al., 2021; Ren et al., 2022; Wang et al., 2022), the dynamic response prediction of offshore wind turbines (OWT) under the action of sea ice has become a hot issue in the structural design and safe use. However, the research on ice-OWT collision mechanism is still insufficient, at present.
The interaction between ice and OWT structures is a complex process, which mainly includes the local crushing failure and bending failure of sea ice, and the accumulation, slippage and removal of broken ice (Riska et al., 1995; Aksens et al., 2010). These processes interact and couple each other, which propose challenges to the numerical simulation of sea ice-OWT interaction and the accurate prediction of ice load (Liu et al., 2022). Each failure shall change the geometry and boundary conditions of the subsequent ice, which can have an impact on the subsequent ice destruction (Kuutti et al., 2013). After the ice sheet produces fragments ice due to crushing and bending, a small part of the ice fragments will rotate and slide until it is removed, and most of the ice fragments will form an accumulation effect in front of the structure. The accumulation effect plays an important role in the ice-structure interaction was discovered by Määttänen (1986) and Sanderson (1988).
