【作者】 刘勇；

【导师】 王雪仁；

【作者基本信息】 哈尔滨工程大学 ， 船舶与海洋结构物设计制造， 2023， 硕士

【摘要】 随着全球气温的持续升高,两极地区海冰范围和冰体厚度也会随之减小,开通北极航道也存在可能,这将大幅度缩短亚欧国家的运输道路,降低运输成本,所以破冰船作为两极资源探索和运输的重要交通工具,其研制与建造成为全球大国关注的热点话题。破冰船在航行过程中,将不可避免的遇到平整冰冰况,在进行破冰作业时,破冰船会受到冰层碰撞产生的随机破冰载荷的影响,容易产生较为强烈的振动情况,影响工作人员的工作效率,同时也有可能对船上配备的精密设备产生不良影响或者导致仪器损坏的风险,所以,开展破冰船破冰复杂多模态振动响应研究具有重要意义。本文将以探究破冰船冰致复杂多模态振动响应以及不同参数下振动响应规律研究为目标,通过理论分析,数值仿真开展相关研究工作。本文首先重点揭示了研究发展破冰船的重要意义,总结整理了国内外破冰船发展现状,国内外学者在冰体特性,破冰载荷以及船冰碰撞方面的研究现状,确定了本文关于破冰船破冰载荷计算方法,破冰船典型甲板区域振动响应以及不同参数下振动响应规律研究的探究方向。介绍了冰体物理和力学特性,为破冰船破冰有限元模型提供冰体材料参数输入;基于LS-Dyna有限元软件,建立钢板挤压球头冰数值模型,将压力面积曲线结果与ISO规范标准和实验数据对比,验证弹性断裂失效模型模拟冰材料的有效性,为下文破冰船破冰载荷模拟计算奠定基础。建立破冰船破冰有限元模型,开展船舶破冰载荷特性研究,利用LS-Dyna流固耦合ALE算法,探究破冰船连续式破冰（连续平整冰排）时破冰载荷的特性规律。阐述船舶破冰过程中的冰层破坏模式,研究船舶航速和平整冰厚度两种敏感参数影响下的破冰载荷变化趋势,并将破冰载荷的数值模拟结果与Jeong^[58]公式经验值进行对比分析,结果表明误差均在10%范围内,破冰载荷数值仿真结果合理;对破冰载荷进行频域分析,分析航速与冰厚对于频谱曲线的影响,为后续开展船舶破冰复杂多模态振动响应研究提供载荷输入。建立破冰船流固耦合有限元模型,进行破冰船自由振动特性分析,探究破冰船总体模态和典型甲板区域局部模态特性,由于板,纵横肋骨,横纵舱壁等多种构件刚度存在差别,存在不同局部模态相互影响,导致破冰船总体模态改变,呈现复杂的多模态现象;以第三章得出的破冰载荷作为激励力,以破冰船航速和平整冰排厚度作为影响参数,探究破冰载荷激励下破冰船典型甲板区域的振动响应特性规律,结果表明随着破冰船航速的增大和平整冰排厚度的提高,典型甲板区域选定的考核点振动加速度均有增大趋势,为后文破冰船典型甲板区域的不同结构参数下振动响应规律研究作支撑。最后,通过改变板厚和肋骨尺寸,开展破冰船典型甲板区域的不同结构参数下振动响应规律研究。以板厚和加强筋截面形式作为控制参数,分别对破冰船典型甲板区域进行振动响应规律研究,从而为破冰船典型甲板区域振动控制提供参考建议。更多还原

【Abstract】 With the continuous rise of global temperature,the extent of sea ice and the thickness of ice body in the polar regions will also decrease,and it is also possible to open the Arctic shipping route,which will greatly shorten the transportation road of Asian and European countries and reduce the transportation cost.Therefore,as an important means of transportation for the exploration and transportation of polar resources,the development and construction of icebreaker has become a hot topic of global powers.In the process of sailing,icebreaker will inevitably encounter flat ice conditions,in the ice breaking operation,icebreaker will be affected by random ice breaking load caused by ice collision,easy to produce strong vibration,affecting the work efficiency of staff,but also may have adverse effects on the precision equipment equipped on board or lead to the risk of instrument damage,so,It is of great significance to study the complex multi-mode vibration response of icebreaker.The objective of this paper is to explore the complex multi-mode vibration response of icebreaker caused by ice and the vibration response rule under different parameters.Relevant research work is carried out through theoretical analysis and numerical simulation.First of all,this paper focuses on the significance of research and development of icebreakers,summarizes the development status of icebreakers at home and abroad,and the research status of domestic and foreign scholars in terms of ice body characteristics,icebreaking load and ship ice collision,and determines the research direction of this paper on icebreaker icebreaking load calculation method,typical deck area vibration response of icebreaker and vibration response rule under different parameters.The physical and mechanical properties of the ice body are introduced,and the input of the material parameters of the ice body is provided for the finite element model of icebreaker.Based on LS-Dyna finite element software,a numerical model of steel plate extrusion ball ice was established,and the results of pressure area curve were compared with ISO standards and experimental data to verify the effectiveness of the elastic fracture failure model in simulating ice materials,which laid the foundation for the following icebreaker load simulation calculation.The finite element model of icebreaker was established,and the characteristics of ship’s icebreaking load were studied.LS-Dyna fluid-structure coupling ALE algorithm was used to explore the characteristics of icebreaker’s icebreaking load in continuous icebreaker（continuous ice leveling）.The ice failure mode in the icebreaking process of ships is described,and the change trend of icebreaking load under the influence of ship speed and flat ice thickness are studied.The numerical simulation results of icebreaking load are compared with the empirical value of Jeong’s formula^[58].The results show that the error is within 10%,and the numerical simulation results of icebreaking load are reasonable.The icebreaking load is analyzed in frequency domain to analyze the influence of ship speed and ice thickness on spectral curve,which provides load input for subsequent research on complex multi-mode vibration response of ship icebreaking.A fluid-to-solid coupling finite element model of icebreaker was established to analyze the free vibration characteristics of icebreaker,and explore the overall mode characteristics of icebreaker and local mode characteristics of typical deck area.Due to the different stiffness of various components such as plate,vertical and horizontal ribs,transverse and longitudinal bulkhead,there are different local modes influencing each other,resulting in the overall mode changes of icebreaker,presenting a complex multi-mode phenomenon.Taking the icebreaking load obtained in Chapter 3 as the excitation force and icebreaking speed and ice leveling thickness as the influencing parameters,the vibration response characteristics of typical deck area of icebreaking ship under the excitation of icebreaking load are explored.The results show that with the increase of icebreaking speed and ice leveling thickness,the vibration acceleration of selected test points in typical deck area tends to increase.This study provides support for the study of vibration response rules under different structural parameters in typical deck area of Houwen icebreaker.Finally,by changing plate thickness and frame size,the vibration response law of typical deck area of icebreaker is studied under different structural parameters.Taking plate thickness and section form of stiffeners as control parameters,vibration response rules of typical deck area of icebreaker were studied respectively,so as to provide reference suggestions for vibration control of typical deck area of icebreaker.更多还原