极地船舶冰区操纵性能的六自由度离散元分析

极地船舶操纵破冰性能是破冰船设计建造过程中需重点考虑的问题。为分析极地船舶操纵性能,本文发展了冰区船舶六自由度操纵破冰运动模型,采用扩展多面体离散元模拟海冰,舵桨操纵模型提供破冰力。开展平整冰区定常直航模拟计算,并与Lindqvist船体冰阻力经验公式展开对比验证;开展雪龙号敞水35°舵角操纵性仿真,并与实船试航结果进行对比。在此基础上,开展冰厚及舵角影响下的船体结构冰载荷及破冰轨迹计算,模拟得到操纵破冰航行中船体垂荡、横摇及纵摇运动时程;最后分析操纵破冰船体线载荷分布与直航破冰下的差异。

Maneuverability analysis of polar ship based on six-degrees-of-freedom discrete element method

The maneuvering and ice breaking performance of polar ships is an important issue to be considered in the design and construction of icebreakers.In order to analyze the maneuverability of polar ships,a six-degree-of-freedom (6-DOF) model for maneuvering ice-breaking motion of ships in ice regions is developed in this paper,in which the dilated polyhedral discrete element method is used to simulate the sea ice field,and the rudder and propeller maneuver is used to provide the maneuvering force.The ice load on the hull structure is simulated by steady straight ice breaking in level ice,and compared with Lindqvist''s formula of hull ice resistance.The maneuverability of Xuelong ship under 35° rudder angle in open water is carried out and compared with the results of real ship trial.On this basis,the calculation of ice load and ice breaking trajectory of ship structure under the influence of ice thickness and rudder angle is carried out,and the time histories of heave,roll and pitch motion of the ship hull during ice breaking are determined;Finally,the difference between the line load distribution of maneuvering ice breaking hull and direct navigation ice breaking is analyzed.