DataSheet1_A CFD-DEM-FEM coupling method for the ice-induced fatigue damage assessment of ships in brash ice channels.pdf

Polar transport ships frequently traverse in the brash ice channel opened by icebreakers. Although the substantial ice resistance caused by direct collisions with the level ice is avoided, the hull still encounters collisions with the brash ice, leading to periodic damage and exacerbating the fatigue issues of the hull structure. To address the fatigue challenges faced by ships sailing in the brash ice channels, this paper proposes an ice-induced fatigue damage assessment method based on the CFD-DEM-FEM. Referring to the brash ice model test conducted at the Hamburg Ship Model Basin (HSVA), a discrete element ice model and a numerical brash ice tank are established using the CFD-DEM coupling method. The simulated ship-ice interaction is compared with HSVA’s experimental results to validate the reliability of the numerical brash ice tank and ice load. The ice load time history resulting from the ship-brash ice collision is applied to the hull, and the hot spot stress time history under each fatigue sub-condition is calculated using the FEM. The improved rain-flow counting method is employed to determine the stress level of the hot spot stress time history, and the S-N curve method based on the linear cumulative damage criterion is used to calculate the total fatigue damage of hot spots. Finally, the results of the proposed method are compared with those of the LR method. This study can serve as a valuable reference for the ice-induced fatigue assessment of ships navigating in brash ice channels.

极地运输船舶常在破冰船开辟的密集冰块通道中航行。尽管避免了与平坦冰面直接碰撞所造成的巨大冰阻力，但船体仍不可避免地与破冰块发生碰撞，导致周期性损坏，加剧了船体结构的疲劳问题。为解决船舶在密集冰块通道中航行所面临的疲劳挑战，本文提出了一种基于CFD-DEM-FEM的冰诱导疲劳损坏评估方法。参照汉堡船舶模型试验基地（HSVA）进行的破冰块模型试验，采用CFD-DEM耦合方法建立了离散元素冰模型和数值破冰块水池。将模拟的船-冰相互作用与HSVA的实验结果进行比较，以验证数值破冰块和冰荷载的可靠性。由船-破冰块碰撞产生的冰荷载时历应用于船体，并利用有限元方法计算每个疲劳子条件下的热点应力时历。采用改进的雨流计数法确定热点应力时历的应力水平，并基于线性累积损伤准则的S-N曲线法计算热点总疲劳损伤。最后，将所提方法的结果与LR方法的结果进行比较。本研究可为船舶在密集冰块通道中航行时的冰诱导疲劳评估提供宝贵的参考。