破冰结构与冰载荷相互作用下的破坏模式和损伤机理研究

Research of Structure Failure Mode and Damage Mechanism Under Interaction of Ice-breaking Structure and Ice Load

文章首先利用LS-DYNA建立各向同性粘塑性有限元数值模型,并结合ISO推荐压强—面积理论曲线和相关学者的试验数据,验证数值模型的可靠性。其次,比较两种典型破冰结构的破冰机理和破冰效果,对破冰船在行进方向受到的阻力分别与艏部外板倾角和水线面艏部夹角的关系做了讨论。最后,分析了普通船舶船首与冰层碰撞时的损伤特点。结果表明,冰刀式破冰结构的破冰作业效率比压溃式更高,而压溃式破冰结构的安全性要比冰刀式更好;船舶与冰排相撞时,船首的易受损部位主要分布在艏柱后侧临近区域和两侧船—冰接触区域,其中外板吸能最多,横向骨材吸收撞击时所产生的能量多于纵向骨材。因此,要结合实际航行水域的冰情、船舶功能和主机功率等因素,才能选取合适的破冰结构以达到最好的破冰效果,在破冰船船首设计和建造时,应增加船—冰碰撞区域船首外板的厚度,船首结构尽量采用横骨架式结构。

Firstly, this paper established isotropic visco-plastic finite element numerical model by LS-DYNA, then it verified the reliability of the numerical model by combining the ISO recommended pressure-area curve and ice impact experiments data of relative scholars. Secondly, it discussed the relationship between the ice-breaking resistance in the proceeding direction and the dip angle of stem’s shell plating and different contacting waterline angles respectively. Finally, it analyzed the damage characteristics when an ordinary ship’s bow collide the ice layer. The results showed that the efficiency of ice-breaking structure was higher than the crushing type, and the security of the type of crushing ice structure was much better than the ice-breaking structure. When ship-ice collision occurred, it showed that vulnerable parts of the bow were mainly distributed in the region of the adjacent area behind the stem post and the contacting area of ship and ice, among which the shell plating absorbed the most energy, and the energy generated by hitting from the transverse aggregate was much more than the one of longitudinal aggregate. Therefore, by combining the actual sailing waters of the ice、ships function and main power and other factors, we were able to select suitable ice-breaking structure in order to achieve the best effect of ice-breaking. When designing and constructing the ice-breaking ship bow, we should thicken the stem’s shell plating in the collision area of ship and ice, and try our best to apply the transverse frame structure of the bow’s structure.