破冰船冲破冰层的有限元数值仿真研究
80000DWT散货船冰区航行有限元强度分析的开题报告
80000DWT散货船冰区航行有限元强度分析的开题
报告
首先,对于80000DWT散货船在冰区航行时的强度分析,需要确定以下几个问题:
1. 冰区航行环境的特征和影响参数,如冰的类型、密度和厚度、水
深和水温等。
要通过海洋调查、历史统计数据和模型模拟等方法获得。
2. 船体结构设计参数的选择,如船型、尺寸、船板厚度、材料性能等。
要考虑船型的流线型、材料的强度和韧性、结构的防冻性等因素。
3. 确定有限元模型的建立方法和分析步骤,包括几何模型构建、边
界条件的设定、材料应力-应变关系的描述、荷载分析等。
要合理选择计
算方法和软件工具。
4. 分析结果的验证和评估,包括分析结果的精度、可靠性和适用性
的评价,以及方案优化和改进的建议等。
针对以上问题,本课题拟采取以下工作方法:
1. 在调研中了解和分析冰区航行环境的特征和影响参数,通过实验、数值模拟和文献研究等方式获取相关数据。
2. 根据80000DWT散货船的船型和参数,建立有限元模型,并通过灵敏度分析和试验数据验证优化。
3. 运用有限元分析软件进行强度分析,包括结构应力、变形、裂缝
扩展等方面的计算和分析,得出不同载荷条件下船体结构的强度和稳定性。
4. 针对分析结果,评估其合理性和可靠性,并提出优化方案和改进
建议,以便进一步优化船体结构,提高冰区航行的安全性和效率。
本课题的研究目的是为了更好地了解该船型在冰区的航行强度特征,为船舶设计和安全管理提供科学依据,具有一定的理论和实践意义。
极地破冰船的破冰技术发展趋势研究
极地破冰船的破冰技术发展趋势研究作者:何纤纤夏鑫刘雨鸣来源:《中国水运》2020年第06期摘要:本文对国内和国外目前先进破冰技术和学者们对破冰技术的研究进行归纳和整理,重点介绍新涌现的极地破冰船的破冰技术,并对未来破冰船的发展趋势进行研究,为极地破冰船未来发展的研究方向提供有益参考。
关键词:破冰技术;发展趋势;破冰船中图分类号:U674.21文献标识码:A文章编号:1006-7973( 2020) 06-0076-05全球气候变暖导致北冰洋冰川融化加剧,北冰洋的冰域面积不断缩小,这使得北极航道的通航成为可能。
北极航道的开通意味着全球航运格局将发生巨大变化。
2019年1月,中国政府发表了《中国的北极政策》白皮书,以加强北极地区基础设施建设和数字化建设为核心纲领,以北极航道和能源合作开发作为经济投资重心,并与多方共同建设“冰上丝绸之路”。
作为担负开辟航道、运输物资、科研考察任务的极地船舶,在开拓北极航道和发展北极经济圈中扮演着重要角色。
目前中国仅有两艘具有破冰能力的极地破冰船,分别是破冰等级为PC6级的“雪龙”号和PC3级的“雪龙2”号,无法满足日益增长的极地科学研究和战略发展的需求,因此发展和提高各类极地船舶的自主设计能力刻不容缓。
1 国内破冰船技术1.1 破冰船的特点及破冰等级破冰船一般依赖船体线型和动力推进破碎冰层,开辟航道。
为获得更大的破冰宽度,船身长宽比值较小,首柱较为尖削,以一定角度前倾。
总体强度高,首尾和水线区具有结构加强。
破冰船的推进系统多采用多螺旋桨,对螺旋桨和舵有防护装置。
破冰船以柴油机或核动力为动力推进。
总体来说,船体短而宽,船体强度高是破冰船的主要特点[1]。
极地船舶的冰级划分可参考lACS冰级要求,见表1。
1.2 破冰船的破冰方式破冰船在破冰作业时,船艏担任主要的破冰任务,受到集中载荷的作用;船体与海冰发生碰撞,受到冲击载荷的作用。
传统的破冰方式主要有连续破冰法和冲撞破冰法[2]。
冰体爆破的数值模拟与理论分析研究
科技风2021年3月科技创新DOI : 10. 19392/j. cnki . 1671-7341.202107007冰体爆破的数值模拟与理论分析研究李佳庆吉林省水利水电勘测设计研究院吉林长春130021摘 要:本文通过ANSYS/LS-DYNA 数值模拟技术,对冰体爆破进行有效的数值模拟,并对其进行理论分析及验算。
关键词:冰体爆破;流固耦合;数值分析新型聚能破冰技术采用两级爆破,一级冰体爆破钻孔,二级冰体或水中爆破,运用两级爆破,尽可能地发挥爆炸所 产生的能量,从而更好地实现冰体爆破⑴#本文针对聚能破 冰的二级爆破在冰体中爆破进行数值模拟与理论分析研究。
1有限元仿真模型建立本文通过ANSYS/LS-DYNA 软件,选用显式六面体实体单元:SOLID164,建立三维实体模型。
选取1m 冰厚,2m 水高,1m 空气层,并在冰下0. 5m 处放置型号为5kg 炸药器材,建立了冰、水、空气作用的数值模型,进行分析与研究。
模型如下:图1冰体爆破模型1.1计算模型在模型建立过程中,对于冰的材料模型,本文采用材料 库中各项同性断裂模型(MAT_ISOTROPIC_EIASTIC_FAIL-VRE )⑵,在模拟中通过自定义材料属性来建立本构模型。
表1 LS-DYNA 中冰的基本参数变量MID RO G SIGY取值40.9 2.2f10- 2.12f10-变量ETAN BULKEPF PRF取值4.26X10-5.26X10-0.35-4x10-5模型采用装药密度为1.25kg/m 3的TNT 炸药,相关系数取值⑶:A = 741GPa ,B=18GPa ,R 1 = 5. 56,R 2 = 1. 65,$ = 0. 35,已0二3.6。
对于水体和空气本文采用MAT-DULL 模型来描述,此模型描述的材料,在状态方程中可以忽略偏应力,也可以选择 黏度是否需要定义。
表2 LS-DYNA 中水的基本参数变量MID RO PC 取值21-3.0X10-表3 LS-DYNA 中空气的基本参数变量MID RO 取值31.29X10-表中:MID 为材料标识,RO 为质量密度,PC 为断裂压力(小于等于零)。
基于数值仿真与经验公式的船舶破冰阻力预报
准确的海冰材料模型是保证数值模拟结果准确度 的关键,然而由于冰材料的复杂性,国内外对冰材料 本构模型的研究尚未形成共识。本文选取的冰材料模
收稿日期: 2018 – 07 – 28 基金项目: 国家自然科学基金资助项目 (51579121);中国博士后科学基金面上资助项目 (2017M621663);江苏省博士后科研资助项
2. Jiangsu New Yangzi Shipbuilding Co., Ltd., Taizhou 214500, China)
Abstract: Firstly, the appropriate ice material model was selected and verified. By establishing the relevant finite element model of level ice and icebreaker, the continuous icebreaking process of icebreaker under different ice thickness and different ship speeds was implemented by using nonlinear explicit power software Ls-dyna. The resistance of ice calculated from numerical simulation results and empirical formulas which were compared under different ice conditions. Finally, the sensitivity of the main parameters in each empirical formulation was analyzed, and the degree of difference in the impact of each parameter on the ice resistance calculation was obtained, which is of important reference value for ice resistance estimation and related hull structural design.
基于非线性有限元法的船舶冰区破冰数值模拟
基于非线性有限元法的船舶冰区破冰数值模拟
王健伟;邹早建
【期刊名称】《船舶力学》
【年(卷),期】2016(020)012
【摘要】应用非线性有限元法进行了破冰船冰区破冰数值模拟。
通过比较数值模拟结果和试验结果,对冰体材料模型进行了验证;采用该冰体材料模型,对破冰船以不同航速在不同厚度的层冰中破冰航行时的动态响应进行了数值研究,给出了破冰过程中层冰的变形、冰力的大小以及冰的变形能和动能变化,分析了船速、冰层厚度对破冰阻力的影响。
该研究结果对分析破冰船在层冰中破冰时的动态响应特性具有一定的参考价值。
【总页数】11页(P1584-1594)
【作者】王健伟;邹早建
【作者单位】上海交通大学船舶海洋与建筑工程学院,上海 200240;上海交通大学船舶海洋与建筑工程学院,上海 200240; 上海交通大学海洋工程国家重点实验室,上海 200240
【正文语种】中文
【中图分类】U661.4
【相关文献】
1.基于FEM-SPH耦合算法的船舶破冰数值模拟 [J], 胡昕;詹成胜
2.基于非线性有限元法的冰区玻璃钢实验船碰撞性能研究 [J], 胡文进;倪宝玉;白晓
龙;李志鹏;于昌利
3.碎冰区航行船舶阻力预报数值模拟研究 [J], 齐江辉; 郭翔; 陈强; 吴述庆
4.碎冰区航行船舶阻力预报数值模拟研究 [J], 齐江辉; 郭翔; 陈强; 吴述庆
5.基于浮冰区参数化设计的船舶冰阻力数值模拟 [J], 刘为民;涂勋程;谷家扬;庄月昊;陶延武;张忠宇
因版权原因,仅展示原文概要,查看原文内容请购买。
极地船舶冰载荷研究方法综述
装备环境工程第20卷第9期·26·EQUIPMENT ENVIRONMENTAL ENGINEERING2023年9月极地船舶冰载荷研究方法综述许育文,顾学康,赵南,王艺陶(中国船舶科学研究中心,江苏 无锡 214082)摘要:梳理了船冰相互作用时冰载荷的研究方法,从理论分析法、试验方法和仿真模拟方法三个方向进行了分类综述。
首先,阐述了理论分析法中直接计算法和概率法的原理和适用性,着重论述了直接计算法分别在总体冰载荷与局部冰载荷的应用。
其次,重点介绍了试验方法中的室内模型试验和实尺度实测的研究成果和进展,并指出试验方法在海冰制备、设备环境等方面的研究难点。
然后,比较分析了仿真模拟方法中的有限元法和离散元法,简述了各自的优缺点与适用范围,认为有限元法在分析结构失效、断裂等过程中有一定的优势,但对冰的破碎过程的模拟则不如离散元法。
最后,讨论总结了船冰相互作用时冰载荷研究方法发展趋势和存在的问题,为领域学者提供一定的参考。
关键词:极地船舶;冰载荷;理论分析法;试验法;有限元法;离散元法中图分类号:U611.4 文献标识码:A 文章编号:1672-9242(2023)09-0026-15DOI:10.7643/ issn.1672-9242.2023.09.003Review of Investigation Methods for Ice Load on Polar ShipsXU Yu-wen, GU Xue-kang, ZHAO Nan, WANG Yi-tao(China Ship Scientific Research Center, Jiangsu Wuxi 214082, China)ABSTRACT: The work aims to sort out the research methods of ice load during ship ice interaction and make a review from three aspects: theoretical analysis, experimental methods, and simulation. Firstly, the principle and applicability of direct calcu-lation method and probability method in theoretical analysis were expounded, and the application of direct calculation method in global ice load and local ice load was emphasized. Secondly, the research achievements and progress of laboratory model test and real scale measurement were introduced, and the difficulties in sea ice preparation and equipment environment of the test method were pointed out. Then, the finite element method and discrete element method were compared and analyzed, and the advantages and disadvantages and application range of each method were described. The finite element method had certain ad-vantages in analyzing the process of structural failure and fracture, but the simulation of the ice breaking process was inferior to the discrete element method. Finally, the development trend and existing problems of ice load research methods during ship ice interaction were discussed and summarized, which could provide some references for scholars in the field.KEY WORDS: polar ship; ice loads; theoretical analysis method; experimental method; finite element method; discrete element method收稿日期:2023-07-07;修订日期:2023-09-04Received:2023-07-07;Revised:2023-09-04基金项目:国家自然科学基金青年项目(52001284);江苏省自然科学基金青年项目BK(20200166)Fund:National Natural Science Foundation of China Youth Project (52001284); Jiangsu Provincial Natural Science Foundation Youth Project BK (20200166)引文格式:许育文, 顾学康, 赵南, 等. 极地船舶冰载荷研究方法综述[J]. 装备环境工程, 2023, 20(9): 26-40.XU Yu-wen, GU Xue-kang, ZHAO Nan, et al. Review of Investigation Methods for Ice Load on Polar Ships[J]. Equipment Environmental En-gineering, 2023, 20(9): 26-40.第20卷 第9期 许育文,等:极地船舶冰载荷研究方法综述 ·27·北极地区拥有丰富的油气资源,是未来各国贸易往来的重要航线。
基于非线性有限元法的船舶冰区破冰数值模拟
第20卷第12期 2016年12月船舶力学Journal of Ship MechanicsVol.20 No.12Dec. 2016Article ID:1007-7294(2016)12-1584-11Numerical Simulation of Ship Icebreaking in Level Ice basedon Nonlinear Finite Element MethodWANG Jian-weia, ZOU Zao-jiana,b(a. S c h o o l of N a v a l A rchitecture, O c e a n a n d C ivil E ng in e e rin g; b. S ta te K e y L a b o ra to ry o fO c e a n E ng in e e rin g, S h a n g h a i J ia o T o n g U niversity, S h a n g h a i 200240, C h in a)Abstract: Numerical simulation of an icebreaker advancing in level ice is carried out by using the nonlinear finite element method. An ice material model is verified by comparing the simulation results with experimental data. Using the ice material model, the dynamic response of the ship during icebreaking in level ice of different thicknesses at different speeds is numerically studied. The deformations of level ice, the magnitudes of ice force, the changes of ice deformation energy and k inetic energy during the icebreaking process are presented, and the influences of the ship speed and level ice thickness on the icebreaking resistance are analyzed. The results have a certain reference value for analyzing the dynamic response of an icebreaker in level ice.Key words: icebreaker; level ice; icebreaking resistance; nonlinear FEM;numerical simulationC LC number: U661.4 Document code: A doi: 10.3969/j.issn.1007-7294.2016.12.0080 In tr o d u c tio nDue to the climate change, the melting speed of ice in Arctic region has been accelerating, which makes the marine transportation in Arctic region possible. In these waters, merchant ships need to clear channel with the help of icebreakers to ensure a successful navigation. Besides, since the global economy is developing rapidly, the resource requirements have been increasing. As the land resources being exhausted, the exploitation of energy in ocean and polar becomes urgent, and the scientific investigation of polar energy is only possible by means of icebreaking. Nowadays, a new generation of icebreaker is under researching and developing all over the world; to accurately predict the dynamic performance of an icebreaker in level ice is of particular importance for icebreaker design, and relevant researches have a practical significance.In recent years, some researchers have studied icebreaking resistance of polar ships. Wang et al[1]used two commercial finite element codes (ANSYS and LS-DYNA) to present numerical results of resistance prediction for an icebreaker in level ice. Park et a l[2]applied three methods including empirical analysis, numerical analysis and physical model experiments toReceived date:2016-08-24B iography:W A N G Jian-wei(1989-), m a le, m a s te r ofS hanghai J ia o T o n g U niversity, E-mail: w a n g jia n w e im e@163.co m;Z O U Zao-jian(1956-), p ro fe sso r/tu to r ofS hanghai J ia o T o n g U niversity, E-mail: zjzo u@sjtu.e d .第12期WANG Jian-wei et al: Numerical Simulation of Ship Icebreaking in 噎1585obtain icebreaking resistance of three ore carriers that have different hull forms under the same ship speed and ice thickness. Considering the coupling between continuous ice forces and ship motions, Su et al[3] used a numerical method to simulate ship maneuvers in level ice and solved the equation of three degree-of-freedom rigid body surge, sway and yaw motions. Some other researchers have studied the issues related to structural response of ship-ice collision. Wang et al[4] developed a collision model for nonlinear dynamic finite element analysis on a LNG ship and crushable ice using commercial code DYTRAN. Lee et al[5] established the finite element model of Arctic LNG carriers and predicted impact loadings from ship and iceberg collision. Liu[6] studied the numerical model of ice materials and applied it to dynamic analysis of ship- iceberg collision. Kim et al[7] used finite element model and scale model test to investigate the resistance performance of an icebreaking cargo vessel in pack ice conditions. Yang et a l[8] adopted the method of fluid-structure interaction and established the nonlinear finite element model of collision between ship and ocean platform by taking sea ice as medium. They simulated the collision process numerically, compared the results of collision under conditions with and without sea ice medium and analyzed the influence of the range of sea ice on platform. Zhang et al[9-10] performed a numerical simulation of ship-ice collision by using a nonlinear finite element method.This paper conducts a numerical simulation study on the dynamic response of an icebreaker in level ice by using the commercial software LS-DYNA based on the nonlinear finite element method. The reliability of the proposed ice material model is firstly verified; the 3D finite element models of ship and level ice are established. The deformation of level ice, the ice force and the ice deformation energy and kinetic energy during the icebreaking process are predicted by numerical simulation, and the influences of ship speed and ice thickness on the icebreaking resistance are analyzed.1 M a th e m a tic a l m o d e lIn the finite element method, the motion equation of ship in level ice can be described asMx+Cx+Kx=F (1)where M is the mass matrix, C is the damping matrix, K is the stiffness matrix, x is the dis-e x t placement vector, and F is the external load vector.It is assumed that the acceleration remains the same in one time step. The explicit central difference method is used to discretize the motion equation, and the solving formula can be derived as心士卜币-士 )+1丨At , +At X(tn+1 网%叫'4)气"T 11 T T1586船舶力学第20卷第12期t i =1 蓸 W i ),t i =i 蓸 W i )n —2 2 n +2^t 1 =1 蓸 ^tn +^tn +1 蔀 > ^tn =蓸 tn-tn -1 蔀 > ^t n +1 =蓸 tn +1 -tn 蔀n +7 2⑵where x (tn) is the node acceleration vector at the time step tn , x (tn +1/2) is the node velocity vector at tn +1/2, and x (tn+1) is the node displacement vector at tn +1. Using this recursion formula, the nodal displacement, velocity and acceleration at each time step can be obtained.2 N u m e ric a l m o d e lin g o f ice m a te ria lIn the numerical simulation of ship-ice collision, the constitutive model of ice is very important and difficult to construct. Referring to the research results of Yang et al[8], the isotropic elastic plastic material with failure is chosen as the ice material model. It adopts the von- Mises yield criterion as the failure criterion of sea ice. Failure is assumed to occur if either n +1 p p n +1 p p <pm in or 着e ff >^m a x , where p is the pressure at t n 1,着e ff is the effective plastic strain; pm inp and 着m a x are the user-defined parameters. The ice model characteristics are given in Tab.1.Tab.1 Ice model characteristicsM a s s d e n sity (kg /m 3)S h e a r m o d u lu s (G P a )Yield s tre s s(M P a )P la stic h a rd e n in g m o d u lu s (G P a )Bulk m o d u lu s P la stic failure (G P a ) stra in F ailure p re s s u re (M P a )9002.202.124.265.26 0.35-4In order to verify the ice material, the reaction generated from the extrusion on ice cone by steel plate is calculated. The finite element model is shown in Fig.1. The fixed boundary condition (fixed B.C.) is applied at ice cone bottom to implement the conditions attached to the testing machine. A steel plate attached on the top of the testing machine is moving downwards at a specified velocity v. Two body contact simulation is performed. The material property of the steel plate is taken as a rigid body, because the plate is thick enough to be considered as rigid. The characteristics of the steel material model are shown in Tab.2.Tab.2 Steel m aterial model characteristicsM a s s d e n sity(kg /m 3)M a s s d e n sity (G P a )P oisson's ra tio 7 8502.000.3The numerical simulation model developed in this study is verified by comparing the results of numerical simulation with the test results of Ref.[11]. An ice cone with 10cm diameter and120° c o n in g a n g le is ch o s e n fo rth e te s t.T h e m a in fo cu so fd e ve lo p in g a n u m e ric a lsim - ulation model is to create a model that can be directly applied to a diverse condition suchas第12期WANG Jian-wei et al: Numerical Simulation of Ship Icebreaking in 噎15870 J . :0 1510Diaplaconf! znt (m m )(a ) Steel plate speed, 1 mm/s Fig.2 Comparison of ice force-displacement curves at different steel plate speeds, case 1From Fig.2 it can be seen that the numerical and experimental results agree well to a certain extent and the error at low speed is smaller than that at high speed. No matter at low speed or at high speed, the calculated results exhibit the correct growth trend of ice force with displacement. The ice force fluctuates at some displacement, because that as the steel plate is pressing the ice body, the phenomenon of broken occurs, causing immediately the drastic changes of ice force.In order to verify the reliability of the ice material model further, it is applied to a larger ice co n e w ith 25c m d ia m e te ra n d 130° coningangle.Thenum ericalandexperim entalresults of ice force-displacement curves at the steel plate speed 1 mm/s and 100 mm/s are compared in Fig.3. From this figure it can be seen that the growth trends of the calculated and experimental ice forces agree well, and they both show the fluctuation generated from the ice body?s fracture. The higher the steel plate speed is, the larger the fluctuation amplitude is. These results indicate that the ice material model selected in this paper can be used for numerical sim-Fig.3 Comparison of ice force-displacement curves at different steel plate speeds, case 2different strain-rate or ice size. In other words, the aim is to create a numerical simulation model that can be used in multiple conditions without any modification of ice material properties or simulation conditions. The application of the ice material model under different strain- rate conditions are investigated firstly, setting steel plate speed v =1 mm/s and 100 mm/s respectively. The comparison of the ice force-displacement curves at different steel plate speeds is shown in Fig.2.10 In :0 35D i j p fc w rM u t (o in j (b) Steel plate speed, 100 mm/s^LrHLJ—1588船舶力学第20卷第12期ulation of the collisions between ship and ice.3 N u m e ric a l s im u la tio n o f s h ip in le vel ice3.1 3D fin ite element model of an icebreakerAn icebreaker is selected in this paper, whose particulars are listed in Tab.3.For the real ship, high-strength steel is used in Tab.3 Ship characteristicsship bow, whose deformation can be ignored during L e n g th over~Breadth D e p th D a ft~ the icebreaking process. Therefore, in order to sim- all(m)______(m)_______(m)______(m)plify the model, the hull plate is regarded as rigid and 6017______84_______35______2 8the internal structure is ignored in the numerical simulation. For the motion states of the ship, regardless of the influence on ship motion in icebreaking process, the ship is set to move forward at a constant speed, and the other five degrees of freedom of motionare constrained.3.2 3D fin ite element model of level iceDuring the icebreaking process, the mechanical properties of level ice are internal factors which affect fracture of level ice and are the basis of study on icebreaking resistance. During the process of ship-ice collision, ice w ill be broken when the ice stress reaches a certain value. The interaction between ice and ship w ill show different damage forms, which immediately influence the ice load on ship.In general, there are four forms of ice failure, including crushing failure, buckling failure, shear failure and bending failure1121.For establishing 3D finite element model of level ice, solid element is used considering the ice thickness and generation as well as extension of cracks. There are two methods to simulate the generation and extension of cracks. One is that cracks are generated in the structure by element failure; the other one is that cracks are generated by defining the failure of constraint nodes. The first method requires that there is a dense grid in cracks of the model; the shortcomings of the second method is that the process of establishing the model is relatively complex1131. In this paper, the first method is chosen to establish the model. When the stress and strain of the finite element model exceed a certain value, the element w ill be of failure, and the element w ill be deleted from the model. Cracks occur when numerous elements are deleted from a path. That is why the grids of level ice should be divided densely. In this paper, the size of the solid element is 125 mmx125 mmx125 mm.The icebreaking resistance when the ship sails in infinite level ice is studied. Different from floating ice, infinite level ice can be regarded as fixed. Limited by the conditions of numerical simulation, size of the level ice cannot be established infinitely. In this paper, the length of the level ice along the longitudinal direction (X-direction) is taken as 40 m, and the length perpendicular to the longitudinal direction (Y -direction) is 80 m. The boundary that collides with the ship is the free end. The influence of the collision area on far-field of the level ice is so small that it can be neglected; hence the far-field boundary is simplified as rigid fixed.第12期WANG Jian-wei et al: Numerical Simulation of Ship Icebreaking in 噎15893.3 A pplication of flu id-s tru c tu re interactionIn the icebreaking process, the buoyancy and gravity of ice need to be considered. Gravity is loaded through body force and the gravitational acceleration is 9.81 N/kg. The load of buoyancy is realized by utilizing fluid-structure interaction.There are three basic algorithms about 3D finite element in LS-DYNA. They are Lagrange, Euler and ALE (Arbitrary Lagrange-Euler) formulations. Solid structures usually adopt Lagrange formulation, whose element is attached to the material and is deformed with the change of the structure5s form. As for fluid-structure interaction, the flow of material may result in serious deform of finite element. Thus it may cause the difficulty of numerical simulation and end the operation of the program. Euler formulation can be understood as the fact that two layers of mesh overlap with each other. One layer is fixed in the space and the other one is attached to the material; it flows in the space grid with the material and is achieved through the following two steps: The material grid firstly performs a Lagrange step, and then the state variables of Lagrange elements are reflected in or transported to the fixed space grid. This grid is always fixed and indeformable,just as material flowing in the grid. Like the Euler formulation, in ALE the space grid can be interpreted as two layers of grids overlapping. But it can freely flow in the space. ALE and Euler formulations can overcome the difficulty of numerical simulation caused by serious deforms of element and implement the dynamic analysis of fluid-structure interaction.This paper simulates the dynamic process of fluid-structure interaction with LS-D YNA and ALE formulation. Through the load of gravity on water and air, pressure gradient is generated in the vertical direction and the buoyancy on the ice is simulated.Fluid materials in the numerical model include water and air. In the finite element model, these two materials have the same nodes. The length and width of water and air are the same as those of level ice. However, the height of water is 4 times of the draft and the height of air is 1.5 times of the draft.Both of water and air adopt null material model to simulate the materials having fluid behaviors and linear polynomial state equation,whose pressure is calculated as232p=c0+c 1滋+c2滋 +c3滋 + (c4+c5^+06滋)E (3)1 where ci (i=0, 1, 2,噎6) are the coefficients; E is the internal energy of unit volume,滋=V-1,V is the relative volume.3.4 S hip-ice contact modelThere are a lot of contact models in LS-DYNA, including node-to-surface contact, surface-to-surface contact and single-surface contact. Considering the failure of ice material and the penetration phenomenon generated during the collision, this paper adopts eroding-surface- to-surface contact model. This model is very useful and is generally applied in the contacts of various shapes and large contact areas.1590船舶力学第20卷第12期Fig.5 Deformation of the level ice Fig.6 Time history of ice force on ship inY direction Fig.7 Time history of ice force on ship in Z direction4 R e s u lts a n d a n a ly s is o f n u m e ric a l s im u la tio nAs shown in Fig.4, the water plane of the level ice is consistent with that of the ship. In the simulation, the ship speed is 2 m/s. The distance between the ship and the level ice is 0.1 m before simulation and simulation time is 8.0 s.Fig.4 FE model of ship icebreaking in level ice4.1 Results of num erical sim ulation of icebreaking processThe deformations of the level ice at 2.0 s, 4.0 s, 6.0 s and 8.0 s are shown in Fig.5. It can be seen in Fig.5 that the deformation mainly occurs in the area of ice contacting and colliding with the icebreaker. After colliding with the ship, the ice failure occurs when the failure pressure is reached. The cracks are generated by elements deleted for failure. During the icebreaking process, because of the brittleness of the ice material, some ices are separated from the level ice and flow in the water.(a ) 2.0 s(b) 4.0 s (c) 6.0 s (d) 8.0 s f^ff ^5X 1M 3W 12A 11K1第12期WANG Jian-wei et al: Numerical Simulation of Ship Icebreaking in 噎1591The time histories of ice force on the ship in Y direction and Z direction are shown in Fig.6 and Fig.7, respectively. From these figures it can be seen that during the whole period, the ice force presents highly nonlinear characteristics and changes violently with time, with a general rising trend. From the analysis of the time histories of ice force in Fig.6 and Fig.7 and the deformation of level ice in Fig.5, it is known that the unloading phenomenon is generated by ice failure as the ship moves in the level ice.4.2 Influence o f ship speedIn order to study the influence of ship speed on the icebreaking resistance,numerical simulation is carried out for the ship sailing in the level ice of thickness 0.5 m at the speed 2m/s, 3 m/s and 4 m/s.The time histories of the icebreaking resistance at different ship speeds are shown in Fig.8. It can be seen that the ship speed has a significant influence on the icebreaking resistance and the amplitude and peak value of icebreaking resistance increase with the ship speed. The common point of the time histories at different ship speeds is that as the icebreaking resistance rises, it w ill suddenly drop. It shows an unloading phenomenon during the icebreaking process because of the ice element failure.(a) Ship speed 2 m/s (b) Ship speed 3 m/s (c) Ship speed 4 m /sFig.8 Time histories of the icebreaking resistance at different ship speedsThe time histories of the level ice deformation energy and kinetic energy at different ship speeds are shown in Fig.9. It can be seen that the level ice deformation energy and kinetic energy increase with the ship speed.Tirns (sj (a ) Deformation energy Fig.9 Time histories of level ice deformation energy and kinetic energy at different ship speeds Time (aj (b) Kinetic energy.(I 1.n l i ^1香^:i •?fS 2X 12fU EIJ1592船舶力学第20卷第12期(a) Ice thickness 0.25 m (b) Ice thickness 0.50 m (c) Ice thickness 0.75 mFig.10 Time histories of the icebreaking resistance under different ice thicknessesThe time histories of level ice deformation energy and kinetic energy under different ice thicknesses are shown in Fig.11. It can be seen that the level ice deformation energy and kinetic energy increase with the ice thicknesses.5 C breaker during icebreaking process in level ice by using finite element method. The ice material model used in the numerical simulation is firstly verified. Systematic numerical simula- tionis are then carried out for the icebreaker at different forward speeds in the level ice of different thicknesses. The following conclusions can be drawn from this study:(1) The ice material model proposed in this paper is used in numerical simulation under ■ 丨 KU1,卩收S r _5ihti £j : ■ ^ D.O&KlO'-0.00 =..-©-3.M r i -^-D .T 5n i i……:-----------r — . — -r .i ■ ■ :■■■■■:■I . ■: v. ': .! ■ ■■ ■!■■■■■ .1 ■■■■■■ ■■/................................................丨...j /---------------------------------------'叫£(a ) Deformation energy 2 14 5Timfi (a|i (b) Kinetic energyFig.11 Time histories of level ice deformation energy andkinetic energy under different ice thicknesseso n c lu s io n sThis paper carries out a numerical simulation study on the dynamic response of an ice-4.3 Influence o f ice thicknessIn order to study the influence of ice thickness on the icebreaking resistance, numerical simulation is carried out for the ship sailing at the speed of 2 m/s in the level ice of thickness 0.25 m, 0.50 m, 0.75 m. The time histories of icebreaking resistance under different ice thicknesses are shown in Fig.10. It can be seen that the peak value of icebreaking resistance increases with the ice thickness. Besides, the time histories show the different degrees of fluctuation for the level ice with different thicknesses. It also shows the unloading phenomenon in icebreaking resistance during the icebreaking process because of the ice element failure.■;3>-.6Js t l3第12期WANG Jian-wei et al: Numerical Simulation of Ship Icebreaking in 噎1593different conditions. The validity of the model is verified by comparing the simulation results with those of experiment. It is shown that the material model can be applied in numerical simulation of icebreaking process;(2) Keeping the ice thickness unchanged, the peak values of ice force, level ice deformation energy and kinetic energy increase with ship speed;(3) Keeping the ship speed unchanged, the peak values of ice force, level ice deformation energy and kinetic energy increase with ice thicknesses;The results of this study can provide a certain reference for the design of icebreakers to be served as icebreaking in level ice.References[1] W a n g J, Derradji-Aouat A. N um e rica l prediction for re s is ta n c e of C a n a d ia n iceb rea ke r C C G S T erry F o x in le v e l ice[C]//IC S O T2009, In tern atio n a l C o n fe re n ce o n S h ip a n d O ffs h o re T e ch n o lo g y. B u s a n, K o re a, 2009: 9-15.[2] P ark K D, C h u n g Y K, J a n g Y S, e t al. D evelopm ent of hull fo rm s for a190,000 D W T icebreaking o re carrier[C]//O M A E2011, 30th International C o n fe re n c e o n O c e a n, O ffsh o re a n d Arctic E ng in e e rin g. R o tte rd a m, th e N e th e rla n d s, 2011, 1: 949-955.[3] S u B, R iska K, M o a n T. A n u m e rical m e th o d for th e prediction of sh ip p e rfo rm a n ce in le ve l ice[J]. C o ld R e g io n s S c ie n c eandTechnology,2010,60⑶:177-188.[4] W a n g B, Yu H C, B a s u R. S h ip a n d ic e collision m o d e lin g a n d s tre n g th e v a lu a tio n o f L N G sh ip structure[C]// O M A E2008,27th International C o n fe re n ce o n O ffs h o re M e ch a n ics a n d Arctic E ng in e e rin g. E storil, P o rtu g a l, 2008, 3: 911-918.[5] L e e S G, L e e J S, B a e k Y H, e t a l. S tructural s a fe ty a s s e s s m e n t in m em brane-type C C S in L N G C u nder ice b e rg collisions[C]// IC S O T2009, In tern atio n a l C o n fe re n c e o n S h ip a n d O ffs h o re T e ch n o lo g y. B u s a n, K o re a, 2009: 69-81.[6] Liu Z. Analytical a n d n u m e rical a n a lysis of ice b e rg collisions w ith sh ip stru ctu re s[D]. T ro n d he im: N o rw e g ia n U niversity o fS c ie n ce a n d T e ch n o lo g y, 2011.[7] K im M C, L e e S K, L e e W J, e t a l. N um e rica l a n d e xp e rim e n ta l inve stig a tion o f th e re s is ta n c e p e rfo rm a n ce of a n iceb reakingc a rg o v e s s e l in pa ck ic e co n ditio ns[J]. In tern atio n a l Jo u rn a l of N a v a l Architecture a nd O ce a n E ng in e e rin g, 2013,5(1): 116-131.[8] Y a n g L, M a J. N u m e rica l sim u la tio n a n a ly s is for th e collision b e tw e e n o ffs h o re p la tfo rm u n d e r th e s e a ic e m e d iu m[J]. C h in aO ffs h o re P la tfo rm, 2008, 23(2): 29-33. (in C h in e s e)[9] Z h a n g J, W a n Z Q, C h e n C. R e s e a rc h o n stru ctu re d yn am ic re s p o n s e o f b u lb o u s b o w in ship-ice collision lo a d[J]. J o u rn a lof S h ip M e ch a n ics, 2014, 18(1): 106-114. (in C h in e s e)[10] Z h a n g J, Z h a n g M R, W a n Z Q, e t a l. R e s e a rc h o n ic e m a te ria l m o d e l applied in n u m e rical sim ulation of sh ip stru ctu rere s p o n s e u n d e r ice b e rg C ollision[J]. S hipbuilding o f C h in a, 2013(4): 100-108. (in C h in e s e)[11] K im H. S im ulation of c o m p re s siv e耶cone-shaped爷ic e s p e c im e n e xp e rim e n ts u sin g LS-DYNA[C]//13th In tern atio n a l LS-D YN A U s e rs C o n fe re n c e. D etro it, A m erica, 2014.[12] W ei W D, N in g J G. C ritical lo a d b e tw e e n s e a ic e a n d s e a stru ctu re[J]. Jo u rn a l of G la cio log y a n d G e o cry o lo g y, 2003, 25(3): 351-354.[13] B a i Z J. T h eo retica l b a s is a n d e xa m p le a n a lysis of LS-DYNA3D[M]. B eijing: S cie n ce P re s s, 2005. (in C h in e s e)1594船舶力学第20卷第12期基于非线性有限元法的船舶冰区破冰数值模拟王健伟a,邹早建a,b(上海交通大学a.船舶海洋与建筑工程学院;b.海洋工程国家重点实验室,上海200240)摘要:应用非线性有限元法进行了破冰船冰区破冰数值模拟。
船首结构冰致动力响应的准静态等效研究
本文网址:/cn/article/doi/10.19693/j.issn.1673-3185.03074期刊网址:引用格式:赵瑾, 王燕舞, 李哲, 等. 船首结构冰致动力响应的准静态等效研究[J]. 中国舰船研究, 2023, 18(6): 158–166.ZHAO J, WANG Y W, LI Z, et al. Quasi-static equivalent study on ice induced dynamic response of bow structure[J].Chinese Journal of Ship Research, 2023, 18(6): 158–166.船首结构冰致动力响应的准静态等效研究扫码阅读全文赵瑾1,王燕舞2,李哲3,冯国庆*11 哈尔滨工程大学 船舶工程学院,黑龙江 哈尔滨 1500012 中国船舶及海洋工程设计研究院,上海 2000113 北京强度环境研究所,北京 100076摘 要:[目的]随着极地探索的不断发展,针对冰区航线的船体结构设计不再局限于传统的经验公式方法,人们更加关注作用于结构上的实际冰载荷及结构响应,研究冰载荷作用下的结构响应计算成为极地船舶结构设计中的关键部分。
[方法]首先,通过有限元方法对某极地航行船舶遭遇的碎冰、浮冰、层冰等冰载荷工况进行数值仿真,考虑材料应变率影响,计算冰载荷作用下的结构动态响应;然后,以结构响应等效为基准,进行动态响应的静态转换,并提出动静转化系数的概念;最后,给出不同冰载荷工况下动静转化系数的取值范围。
[结果]结果表明,船首结构在不同工况下动载荷响应的静载荷等效转换计算的转换系数为1.0~1.4之间。
[结论]船首结构冰致动力响应的准静态等效方法是合理可行的。
关键词:冰载荷;应变率;结构响应;动静转化系数中图分类号: U661.43文献标志码: ADOI :10.19693/j.issn.1673-3185.03074Quasi-static equivalent study on ice induced dynamic response of bow structureZHAO Jin 1, WANG Yanwu 2, LI Zhe 3, FENG Guoqing*11 College of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China2 Marine Design and Research Institute of China, Shanghai 200011, China3 Beijing Institute of Structure and Environmental Engineering, Beijing 100076, ChinaAbstract : [Objective ]As polar exploration develops, hull structure designs for ice routes are no longer lim-ited to the traditional empirical formula method as more attention is paid to the actual ice load and structural response acting on the structure. The study of structural response calculation under ice load is crucial for the structural design of polar ships. [Methods ]First, the finite element method is used to numerically simulate the ice load cases of a polar navigation ship, such as crushed ice, floating ice and layered ice. Considering the influence of the material strain rate, the dynamic response of the structure under ice load is calculated. Second,based on the structural response equivalence, the static transformation of the dynamic response is completed,and the concept of the dynamic static transformation coefficient is proposed. Finally, the range of the dynamic static conversion coefficient under different ice load cases is obtained.[Result ]The results show that the conversion coefficient of the dynamic-static equivalent conversion of the bow structure under different ice load cases is between 1.0 and 1.4.[Conclusion ]The quasi-static equivalent method of the ice-induced dynamic response of a bow structure is verified as reasonable and feasible.Key words : ice load ;strain rate ;structural response ;dynamic static conversion coefficient收稿日期: 2022–09–08 修回日期: 2023–01–15 网络首发时间: 2023–04–10 16:45基金项目: 国家自然科学基金资助项目(52171301)作者简介: 赵瑾,女,1998年生,硕士生,研究方向:船体结构强度。
油船极地航行与浮冰碰撞动响应特性研究
油船极地航行与浮冰碰撞动响应特性研究刘俊杰,王艺陶,赵 南,董海波(中国船舶科学研究中心,江苏 无锡 214082)摘要: 本文采用数值仿真方法研究某PC4级油船在极地碎冰区航行时船首与浮冰发生碰撞时的动响应特性,考虑碰撞引起的冰-水耦合作用,分析浮冰形状及碰撞位置对船体结构响应、船-冰碰撞力特性的影响,研究不同碰撞工况下船体外板的应力分布和冰体破损特征,对油船极地冰区航行操作规程的制定及抗冰结构设计具有指导作用。
关键词:船-冰碰撞;冰-水耦合;数值仿真;碰撞力;结构响应中图分类号:U661.43 文献标识码:A文章编号: 1672 – 7649(2020)12 – 0163 – 06 doi:10.3404/j.issn.1672 – 7649.2020.12.033Analysis on the dynamic response characteristics of oil tankercolliding with floating ice navigating in polar areaLIU Jun-jie, WANG Yi-tao, ZHAO Nan, DONG Hai-bo(China Ship Scientific Research Center, Wuxi 214082, China)Abstract: In this paper, the numerical simulation method was used to study the dynamic response characteristics of a PC4 oil tanker colliding with floating ice. Considering the ice-water interaction caused by collision, the hull structural re-sponse and collision force were analyzed by the influence of ice shape and collision position. The stress distribution of shell plate and ice damage characteristics under different collision case were studied. This research work can be of great signific-ance for navigation rules formulating and hull anti-icing structural designing.Key words: ship-ice colliding;ice-water coupling;numerical simulation;collision force;structural response0 引 言据《美国地理调查》评估,北极地区储存着大约30%的世界已探明天然气资源和13%的世界已探明石油资源[1]。
破冰船推力轴承特性研究
damping coefficient The analysis results show that: For a certain shipꎬ the maximum ice load is approximately
动特性进行分析ꎮ 结果表明:针对某一船舶ꎬ最大冰载荷与船速、冰层厚度近似成正比ꎻ最大冰载荷
出现在碰撞过程中前 1s 的时间内ꎻ油膜厚度随载荷的增加变薄ꎬ油膜刚度系数、阻尼系数随油膜厚
度减小而变大ꎬ且变化规律相同ꎮ
关键词:有限元分析ꎻ冰载荷ꎻ推力轴承ꎻ刚度系数ꎻ阻尼系数
DOI:10. 15938 / j. jhust. 2019. 05. 010
第 24 卷 第 5 期
2019 年 10 月
哈 尔 滨 理 工 大 学 学 报
JOURNAL OF HARBIN UNIVERSITY OF SCIENCE AND TECHNOLOGY
Vol 24 No 5
Oct 2019
Hale Waihona Puke 破冰船推力轴承特性研究李永海1 ꎬ 赵鸿博1 ꎬ 孙向志2 ꎬ 郭晓东1 ꎬ 汪 雷1
中图分类号: TH133 3
文献标志码: A
文章编号: 1007- 2683(2019)05- 0054- 05
Study on Dynamic Characteristics of Thrust Bearing of Icebreaker
LI Yong ̄hai1 ꎬ ZHAO Hong ̄bo1 ꎬ SUN Xiang ̄zhi2 ꎬ GUO Xiao ̄dong1 ꎬ WANG Lei1
极地航行船舶冰力预报的层冰破坏模型
极地航行船舶冰力预报的层冰破坏模型作者:汪玉兰何鸣张强来源:《科技视界》2016年第13期【摘要】随着极地战略的提出,对极地船舶的相关研究受到越来越多的重视。
在对极地航行船舶进行冰力预报前,需要研究层冰的破环机理,建立合适的层冰破环模型。
所有数学模型方法和仿真方法都是建立在一定假设之上的,根据已有的研究基础,本文对极地航行船舶与层冰的相互作用进行理论分析,基于船舶破冰过程中的各种理想化假设,对船舶的破冰过程进行简化,使其在工程计算中具有可行性。
【关键词】层冰;冰力;层冰破坏模型0 前言目前对层冰破坏机理的研究是一个较前沿的课题,冰力预报方法多是基于试验的回归公式,国内现在尚处于研究的起步阶段[1]。
但是经验公式并不能反映层冰的破坏过程,所以有必要研究层冰的破坏过程:岳前进(2003)[2]等人通过试验结果观察得到冰与锥体作用破坏过程,建立确定性的冰力函数,该研究反映了国内初步对层冰破坏机理的探索,函数中部分参数需要通过实验获得;何菲菲(2010)[3]结合弹性力学理论和最小势能原理,提出了破冰船破冰载荷的理论计算公式,该方法只考虑了层冰的弯曲破坏。
国外对船舶在层冰中冰力预报的研究起步比国内早得多,用数值方法进行冰力预报都是基于不同的层冰破坏模型的,Lau.el(2006)[4]基于DECICE计算船舶在冰中的运动,将层冰近似成三维弯曲板元件研究层冰的破坏,Biao Su (2011)[5]运用压毁和弯曲失效模型,模拟了船舶的连续破冰,得到船舶局部冰载荷分布情况。
这些方法中建立层冰破坏模型都要考虑破冰过程的理想化假设、层冰破坏的失效形式、冰力的成分分析、船体与冰接触边缘的几何条件等。
1 层冰破坏模型冰力预报时数值方法不仅可以计算冰阻力还可以描述破冰过程,这就需要对层冰的破冰过程进行研究讨论,建立合适的层冰破坏模型。
1.1 连续破冰过程的理想化假设冰力是一个随机力,船舶运动也决定了冰力的大小,冰载荷的变化外因是冰况的变化,内因是接触形式和破冰形式的变化,船冰相互作用的研究对建立可靠的数值方法预报冰载荷起着关键作用。
黄河破冰船破冰防凌新方法研究(可编辑)
黄河破冰船破冰防凌新方法研究分类号: 密级::单位代码:华北水利水电大学硕士学位论文黄河破冰船破冰防凌新方法研究Ⅶ匣研究生姓名:捏漫洼指导教师:郝恿送数援昱挞蝰副教援专业名称:至揸工程所在学院:扭越堂院年月独立完成与诚信声明四本人郑重声明:所提交的学位论文,是本人在指导教师的指导下,独立进行研究工作所取得的研究成果并撰写完成的。
没有剽窃、抄袭等违反学术道德、学术规范的侵权行为。
文中除已经标注引用的内容外,本学位论文中不包含其他人或集体已经发表或撰写过的研究成果,也不包含为获得华北水利水电大学或其它教育机构的学位或证书所使用过的材料。
对本文的研究做出重要贡献的个人和集体,均已在文中作了明确的说明并表示了谢意。
本人完全意识到本声明的法律后果由本人承担。
保证人导师签名杉易甲/处易学位论文作者签名:径;奇涵签字日期: 签字日期:乃,;.占.≯,,,.多.学位论文版权使用授权书本人完全了解华北水利水电大学有关保管、使用学位论文的规定。
特授权华北水利水电大学可以将学位论文的全部或部分内容公开和编入有关数据库提供检索,并采用影印、缩印或扫描等复制手段复制、保存、汇编以供查阅和借阅。
同意学校向国家有关部门或机构送交论文原件或复印件和电子文档。
涉密的学位论文在解密后应遵守此规定导师签名:三刀八彩学位论文作者签名:檀;鸯滔签字日期口/乡.占..签字日期:.口/.多.摘要黄河破冰船破冰防凌新方法研究摘要黄河凌汛灾害频发,给国家和人民带来严重的经济损失。
现有的黄河防凌措施在凌汛防御中取得了较好的成果,但存在不足。
为了更好的防止凌汛灾害的发生,研究新的防凌措施具有很重要的现实意义。
破冰船破冰机动性强,安全性好,可以沿河而上进行破冰,使碎冰在水的动力作用下沿河而下,避免碎冰二次堆积形成冰坝,用于破冰防凌优点突出。
由于内河对破冰船的要求比较严格,因此内河破冰船的研究相当缓慢。
根据黄河防凌破冰的需求,研究适合黄河的破冰船用于破冰防凌非常有必要。
冰区航行船舶碎冰阻力预报数值模拟方法_郭春雨
1) 保持变形后的物体边界条件,对内部单元进 行 重 分 网 格,网 格 的 拓 扑 关 系 保 持 不 变,称 为 smooth step;
2) 将变形网格中的单元变量( 密度、能量、应力 张量等) 和节点速度矢量输运到重分后的新网格 中,称为 advection step。
近年来,随着全球气候变暖、资源能源紧缺,蕴 藏着巨大潜在价值的北极地区的科考开发工作备受 相关国家重视。由此,破冰船、极地科考船、冰区运 输船等冰区航行船舶的基础性能研究工作也成为当 前的研究热点。目前冰与结构物相互作用的研究领 域内的成果主要集中在冰力学性能[1-2]和冰-固定锥 形结构[3]相互作用的研究领域,船-冰作用的研究进 展有限。而在船-冰作用的研究中,以破冰船和平整 冰碰撞作用[4]的情况为主,对冰区航行船舶在碎冰 区域内的阻力性能预报研究进行的较少,使用的研 究方法通常为理论分析方法或孤立的数值模拟方 法,由于条件限制,船模试验往往很少进行。目前,
A numerical simulation method for resistance prediction of ship in pack ice
GUO Chunyu,LI Xiayan,WANG Shuai,ZHAO Dagang
( College of Shipbuilding Engineering,Harbin Engineering University,Harbin 150001,China)
碎冰区域内的冰区航行船舶阻力性能研究尚处于起 步阶段,研究成果有限,大量问题需要解决。因此, 开展冰区航行船舶在碎冰区域内的阻力性能研究工 作具有重要的价值和意义。
基于有限元法的破冰弹头对海冰侵彻作用研究
基于有限元法的破冰弹头对海冰侵彻作用研究
孟强;张宇庭;张婷婷;常恒瑞
【期刊名称】《科技创新与应用》
【年(卷),期】2024(14)12
【摘要】针对环渤海地区的冬季海冰灾害,现有的破冰方法并不理想,破冰船破冰效率低,小吨位船舶在破冰后仍无法自行出入港口,炮弹炸冰危险性大,且受到作业条件的限制大。
该文设计一种可以用于高厚度海冰的新型破冰弹头,通过建立新型破冰弹头几何模型,添加各向异性材料模型-海冰及Johnon失效准则,利用Autodyn显示动力学软件对其进行海冰的侵彻模拟,通过分析海冰的应力应变曲线以及损伤云图得出,新型弹头模拟侵彻海冰过程中,初生裂纹可以有效帮助爆破二次启动。
【总页数】4页(P67-70)
【作者】孟强;张宇庭;张婷婷;常恒瑞
【作者单位】成远矿业开发股份有限公司;辽宁科技大学矿业工程学院
【正文语种】中文
【中图分类】TJ410
【相关文献】
1.基于局部相互作用理论的侵彻弹头部形状优化及仿真
2.复合结构弹头对多层靶的侵彻效能研究
3.三维编织复合材料抗侵彻性能--准静态侵彻实验与弹道侵彻有限元计算的对比
4.侵彻弹弹头形状设计中摩擦力的作用
5.基于微元法的侵彻体弹头摩擦升温计算方法
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基于SPH方法的连续式破冰数值模拟
基于SPH方法的连续式破冰数值模拟刘亚男,李 辉,刘煜文,杨秋霞, 杨 征(哈尔滨工程大学船舶工程学院,哈尔滨 150001)摘要:根据海冰的力学性质,采用光滑粒子流体动力学(SPH)方法建立海冰本构模型,模拟冰锥实验并与实验结果对比,对冰材料模型准确性进行验证。
利用显式动力分析软件LS-DYNA模拟破冰船连续式破冰,得到了海冰的损伤变形和破冰阻力,同时研究了船舶航速和海冰厚度等参数对冰载荷的影响。
分析研究表明:应用SPH方法建立的海冰模型能够真实的反映海冰的力学性能,对连续式破冰过程实现较为准确的模拟,为船冰碰撞的数值模拟提供了新思路。
关键词:SPH;冰力;数值模拟;冰模型中图分类号:U661.4 文献标识码:ANumerical simulation of the continuous icebreakingbased on SPH methodLIU Ya-nan, LI Hui, LIU Yu-wen, YANG Qiu-xia,YANG Zheng(Harbin Engineering University, Ship Engineering College, Harbin 150001, China)Abstract: According to the mechanical property of the ice, constitutive model of sea ice is established using SPH. The numerical model is validated by comparing the numerical simulation results with the measured data in compressive cone-shaped ice experiments. The damage,the deformation, and the icebreaking resistance of sea ice is obtained by simulating continuous icebreaking with explicit dynamic analysis software LS-DYNA. At the same time, influence of icebreaker speed and sea ice thickness on ice load is studied. The results show: the numerical model using SPH method can reflect on sea ice the real mechanical properties and simulate the process of continuous icebreaking accurately what supplies new thinking for collision simulation of ship and ice.Key words: SPH; ice force; numerical simulation; ice model0 引 言随着全球气候的变暖,极地资源的开发成为可能,此时对极地海冰和极地船舶的研究必不可少,然而目前我对这方面的研究还有所欠缺。
基于SPH法的冰与船舶螺旋桨碰撞数值模拟
第22卷第4期 2018年4月船舶力学Journal of Ship MechanicsVol.22 No.4Apr. 2018文章编号院1007-7294(2018)04-0425-09基于SPH法的冰与船舶螺旋桨碰撞数值模拟桂洪斌^胡志宽u(1.哈尔滨工业大学(威海),山东威海264209;2.中国船舶科学研究中心,江苏无锡214082)摘要:在结冰海域航行的船舶螺旋桨会因受到冰块的撞击而出现严重的损坏。
该文建立了冰一桨碰撞计算模型,冰模型采用SPH(光滑粒子流体动力学)法,运用非线性有限元软件ANSYS/LS-DYNA数值模拟了螺旋桨与冰在 不同速度、位置下碰撞和螺旋桨与不同半径冰碰撞下的动态响应。
对比研究了在以上单一碰撞因素下桨的变形、单元最大应力以及碰撞过程中产生的碰撞力等响应差异,定性地得出上述因素对冰一桨碰撞的影响规律,为船舶螺旋桨抗冰性能的结构设计提供参考。
关键词:船舶螺旋桨;冰;冰一桨碰撞;SPH法中图分类号:U664.33 文献标识码:A doi:10.3969/j.issn.1007-7294.2018.04.005SPH-Based numerical simulation ofship propeller under ice impactGUI Hong-bin^,HU Zhi-kuan1,2(1. School of Naval Architecture and Ocean Engineering, Harbin Institute of Technology at Weihai,Weihai 264209, China; 2. China Ship Scientific Research Center, Wuxi 214082, China) Abstract:Ship propeller is serious damaged by ice impact in freezing seagoing areas.In this paper,ice- blade impact models are established,in which SPH(smoothed particle hydrodynamics)method is used in ice model.The dynamic responses of ice-blade collision with different speeds,impact positions and different radii of ice are simulated by the nonlinear finite element software ANSYS/LS-DYNA.By changing a single collision factor above,different structural dynamic responses of damage deformation of the blade, blade elements maximum stress and impact force are carried out.Then the influence of the above factors is obtained,which provides reference for the structure design of ship propeller under ice impact.Key words:ship propeller;ice;ice-blade impact;SPH method0引言在我国渤海和黄海北部海域,每年入冬均有大量海冰,冰对船舶与海洋结构物的作用和影响一直 受业界的重视。
船-冰作用中海冰典型破坏模式的离散元数值模拟
第38卷第3期2021年6月Vol.38,No.3June2021计算力学学报Chinese Jouriml of Computational MechanicsDOI:10.7511棷—x2()2()1121()02船-冰作用中海冰典型破坏模式的离散元数值模拟雷建奇1,狄少丞灣1,于加一1,王迎晖2(1.哈尔滨工程大学,哈尔滨150()01; 2.中国船舶重工集团有限公司第七曫二研究所,无锡214082)摘要:在破冰船破冰过程中F水排主要表现为挤压与弯曲两种破坏模式。
本文基于黏结离散单元法对船-冰作用中的这两种典型破坏模式进行数值模拟。
海冰离散元数值试样采用随机排布方式生成,采用单轴压缩试验与三点弯曲试验相结合的方式标定模型中的细观参数暎将船-冰碰撞中的挤压和弯曲作用方式简化为直立或倾斜平板与海冰的作用模式1勾建挤压与弯曲破坏的海冰离散元数值试样,分析了挤压破坏模式中不同加载方位以及冰厚和加载速率对破坏模式的影响,以及弯曲破坏模式中不同冰排夹角以及冰厚和加载速率对破坏模式的影响暎计算结果表明,离散元海冰数值模型可以很好地对冰排挤压与弯曲破坏现象进行模拟,可揭示冰排在不同破坏模式下的破坏机理暎关键词:破冰船;冰载荷;船-冰作用模式;离散元法中图分类号:O242.1文献标志码:A文章编号:10074708(2021)0-0346-091引言近年来,极地资源开发以及极地航道开辟越来越受到人们的关注与重视[],冰区船舶作为进行这两项工作的重要载体,如何保证其在冰区航行时的安全性显得尤为重要。
冰区船舶在平整冰区航行时,船体与冰排的相互作用给船体带来的冰载荷对船舶的安全性与适航性有重要影响,船体所受冰载荷主要来源于冰排破碎[]。
对于船-冰相互作用,国内外学者们通过各种手段进行了广泛的研究,但到目前为止人们对于这一问题的理解还十分有限3。
海冰破碎时表现出离散的特性,同时不同尺度下海冰分布也十分离散[N],因此使用离散元方法模拟海冰与结构物的作用具有一定优势[7],能较好地模拟船-冰作用中海冰从完整状态到破碎状态的过程[]。
破冰船冲撞式破冰结构强度数值仿真方法研究
( 1 . 中 国人 民解 放 军 9 1 4 0 4 部 队 ,河北 秦皇 岛 0 6 6 0 0 0 ; 2 . 哈 尔滨 工程 大学 船 舶 工程 学 院 ,黑 龙 江 哈 尔滨 1 5 0 0 0 1 )
摘 要 :本文基 于瞬态动力学分 析法对破冰船 冲撞 式破冰过程进行 有限元数值仿真研 究。针对该 h ‘ 法 f l 的船
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S H I P S C I E NC E AND T E C HNOL OGY
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i c e b r e a k e r d u r i n g c o l l i s i o n wi t h i c e i s c o n d u c t e d a s a n i l l u s t r a t i v e e x a mp l e a n d s t r u c t u r a l s t r e n g t h i s a c c e s s e d . I n s u m ma r i z e , t h e me t h o d p r o p o s e d i n t h i s p a p e r i s o f g r e a t s i g n i i f c a n c e f o r s t r e n g t h e v a l u a t i o n o f i c e b r e a k e r s . Ke y wo r d s : i c e b r e a k e r ;s t uc r t u r a l ;c r a s h — b r e a k i n g; n u me r i c a l s i mu l a t i o n
某破冰船调距机构有限元强度计算
某破冰船调距机构有限元强度计算刘爱兵;周林慧;刘莉莉;田忠殿【摘要】调距桨是破冰船常用的推进型式,DNV GL船级社在破冰船调距机构的强度计算上积累了丰富的经验.文章针对按极地冰区PC-5级强度设计的破冰船调距机构,根据DNV GL规范,采用有限元方法对该调距机构进行了强度计算.首先依照DNV GL规范计算了桨叶失效冰载,然后分2种工况采用有限元仿真计算了在桨叶失效冰载作用下调距机构的强度.计算结果表明:该调距机构强度满足DNV GL规范的要求.【期刊名称】《机电设备》【年(卷),期】2018(035)004【总页数】5页(P84-87,91)【关键词】破冰船;调距机构;有限元;DNVGL规范;强度计算【作者】刘爱兵;周林慧;刘莉莉;田忠殿【作者单位】上海船舶设备研究所,上海 200031;上海船舶设备研究所,上海200031;上海船舶设备研究所,上海 200031;上海船舶设备研究所,上海 200031【正文语种】中文【中图分类】U661.430 引言随着不可替代能源的日趋枯竭,极地丰富的石油、天然气、渔业等资源陆续被发现,以及极地在军事上的战略意义,各国对极地的科学研究和开发日趋重视和活跃。
在此形势下,破冰船自然成为在充满浮冰的极地从事此类活动的重要工具和运输载体[1-2]。
调距桨可以为船舶提供良好的操纵性和较大推力,因此很多冰区航行船舶和破冰船都采用了调距桨[3]。
目前,调距机构强度设计主要是参照船级社规范,DNV GL船级社经过多年的研究积累,发展出较完善的冰区调距机构强度计算方法,并包含到其规范中[4-5]。
本文根据DNV GL极地冰区强度计算规范,采用有限元方法计算了在桨叶失效冰载作用下按极地冰区PC-5级强度设计的某破冰船调距机构的强度。
1 桨叶失效冰载计算DNV GL规范要求调距机构必须满足“金子塔强度设计原则”,即在桨叶失效载荷作用下不能导致调距机构的失效。
这就要求调距机构中的名义等效应力不能超过部件材料的最小屈服强度,即调距机构的强度安全系数不小于1.0。
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元 进 行 建 模 模 拟 。 由于 破 冰 船 在 进 行 破 冰 作 业 的过 程 中 ,主
要依 靠 船 艏 冲 撞 冰 层 来 进 行 破 冰 ,而 其 他 区域 , 由于 远 离 破
变 形 。在 工 程 中 ,对于 固体 结 构 主 要 应 用 此 方 法 来 进 行 分 析 。 对 于 结 构 物 瞬 间 的 动 态 变 化 ,通 常 利 用 显 式 积 分 方 法 来 进 行 模 拟 。这 种 方 法 具 有 计 算 快 、可 自动控 制 步 长 以 及 精 度 高 等
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要: 基于 “ 冲 撞 式”破 冰 法 以 及 有 限 元 仿 真 法 的 原 理 , 利用 MS C. P a t r a n/ Dy t r a n软 件 进 行 冰 载 荷 的 数 值 模 拟 ,
研 究 模 拟 破 冰 船 冲 撞 冰 层 的过 程 中 的关 键 技 术 ,分 析 确 定 适 合 于 本 文 所 用 的 研 究 方 案 ,对 整 个 破 冰 过 程 中冰 层 的变 化 过 程 进 行 分 析 ,并 通 过 对 比不 同 的冲 撞 速 度 、撞 击 角度 以及 冰 层 厚 度 ,研 究 这 些 参 数 的 不 同对 破 冰 船 破 冰 能 力 的
壳单 元 、 梁 单 元 等 。本 文 选 取 的破 冰船 的 主 体 结 构 就 采 用 四
边 形 单 元 进 行 建 模 ,部 分 小 构 件 及 不规 则 区 域 采 用三 角 形 单
节点连接而形成 的, 并 且这 些 节 点都 是 固 定在 分析 对 象 上 的 。
所 以 当对 象 发 生 形 变 时 ,节 点 也 会 随之 移 动 ,进 而 单 元 发 生 一Leabharlann 、数 值 模 拟
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但 是 它 们 都 要 通 过 前 处理 、 求 解 、 后 处 理 这 三个 基 本 环 节 来 进 行 分 析 求 解 , 因此 ,他 们 的 基 本 的 分 析 流 程 大 致 相 似 。
与运 动相 应 。
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响 ,需 要 建 立 整 船 模 型 ,模 拟 是 情 况 是 三 种 建 模 方 法 中最 为 真 实 的 ,也 是 目前 所 能 掌 握 的 最 准 确 的仿 真 分析 方 法 ,且 流 固耦 合 法 的计 算精 度 较 高 ,但 其 建 模 的工 作 量 十 分 巨大 。而 附 连 水 质 量 法 和 等 效船 体 梁 法 ,都 是 一 种 简 化 的 近 似 计 算 方 法 。虽然 流 固耦 合 法 的 精 度 很 高 , 但 在 考 虑 本文 的 实 际情 况 :
此 时 的破 冰船 就和 其 他 船 舶 一 样 , 按照设定的航线进行航行 ,
一
步 的提 高 ; GF法 目前 一 般应 用于 小 尺 度 的 海 冰 动 力 学 的 数
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值模拟试验研 究。 对 海 洋 结 构 物 进 行 有 限 元 动 力 模 拟 分 析 时 , 一 般 会 用 到 三种 建模 方 法 :流 固耦 合 法 、附 连 水 质 量 法 、等 效 船 体 梁 法 。
形 态 作 为 参 考 ,利 用 这 个 参 考 来 描 述 连 续介 质 的 问 题 。在 这 种 方 法 中 , 结构 物 网络 是 有 单 元 组 成 的 ,而 单 元 又 是 有 各 个
在 利 用 大 型 有 限 元 分 析 软 件 进 行 建 模 分 析 时 ,一 般 需 要
先选择有 限元模型单元通 。 通常会采用的模型单元有体单元 、
对 比 以 上 三 种 方法 , 流 固 耦 合 法 由于 为 了 引 入 流 体 的影
此 时 的 破 冰 船 具 有 一 定 的适 航 性 ;如 果 航 行 的海 域 是 一 片 海 冰 区 域 ,且 靠 近 海 岸 ,此 时 ,破 冰船 将 进 行 破 冰 作 业 。在 开 阔 的 水 域 航 行 时 ,决 定 船 舶 运 动相 应 的 控 制 载 荷 主 要 是 破 浪 载 荷 , 与 之 相 比 ,破 冰 船 在 进 行 破 冰 工 作 时 ,破 冰 载 荷 将 代 替 波 浪 载 荷 ,成 为 主 要 的控 制 载 荷 来 决 定 破 冰 船 的破 冰能 力
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片 没 有 水 域 的 冰 区 , 因此 本 文 将 采 用 附连 水 质 量 法 。在 进
行 建 模 的 时候 ,一 般 会 增 大 船 体 的密 度 从 而 使 模 型 的总 质 量 等 于 船 舶 排 水 量 与 附连 水 质 量 之 和 。
( 1 ) 有 限 元模 型
对 于 利 用 数 值 模 拟 方 法 解 决 连 续 介 质 力 学 问 题 ,通 常 有 两 种 方 法 :L a g r a n g e法 和 E u l e r法 ;而 对 于 动 力 学 数值 问 题 , 由分 为 隐式 时 问 积 分 法 和 显 式 时 间积 分 法 。其 中 ,拉 格 朗日 ( L a g r a n g e )法 ,又 名 质 点 坐 标 系 法 ,其 主 要 是 把 参 始
第 1 4卷 第 5期
2 01 4住
中 国
水
运
VoI .1 4
Ma y
No. 5 2 01 4
5月
C h i na Wat er Tr a ns por t
破冰船冲破冰层 的有限 元数值仿真研 究
王 林 , 刘 星
( 江 苏 科 技 大 学 船 舶 与 海 洋 工程 学 院 , 江 苏 镇 江 2 1 2 0 0 3 )