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基于车身模态运动及作动力分配权重的半主动悬架控制方法
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作者 李奕宝 罗谢盼 樊义祥 《汽车零部件》 2024年第4期48-53,共6页
针对整车半主动悬架减振器作动力的分配问题,本文根据车身的模态运动建立了常规分配方法,并以此为基础提出一种全新的基于车身模态运动权重的分配策略。通过仿真求解非线性频率响应,权重高的模态运动对应的幅频特性得到了进一步优化。... 针对整车半主动悬架减振器作动力的分配问题,本文根据车身的模态运动建立了常规分配方法,并以此为基础提出一种全新的基于车身模态运动权重的分配策略。通过仿真求解非线性频率响应,权重高的模态运动对应的幅频特性得到了进一步优化。随后又使用比利时随机路谱进行仿真,通过调整权重,可以实现车身侧倾控制和俯仰控制的明显优化。基于权重的分配方法简单有效,不依赖车辆参数,更具普适性,能与其他控制算法相互补充,具有较大应用场景。 展开更多
关键词 天棚控制 模态运动 作动力分配
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考虑作动器动力学的半车主动互联悬架抗侧倾控制研究 被引量:1
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作者 吴晓建 周兵 文桂林 《振动与冲击》 EI CSCD 北大核心 2017年第12期150-154,共5页
为提高车辆的侧倾稳定性及抗侧翻能力,开展了考虑液压作动器动力学特性的主动互联悬架控制研究。首先建立了主动液压互联悬架动力学模型及液体连续方程,然后以车身侧倾角为控制目标,采用backstepping非线性控制方法完成了抗侧倾控制器... 为提高车辆的侧倾稳定性及抗侧翻能力,开展了考虑液压作动器动力学特性的主动互联悬架控制研究。首先建立了主动液压互联悬架动力学模型及液体连续方程,然后以车身侧倾角为控制目标,采用backstepping非线性控制方法完成了抗侧倾控制器设计及其稳定性分析,通过构造控制目标跟踪函数使控制系统平稳过渡并追踪期望的侧倾角度。角阶跃转向工况抗侧倾模拟分析表明:所设计的控制系统能使车身侧倾角跟踪期望的角度值,有效控制车身侧倾姿态,降低载荷转移率,提高抗侧倾性能及侧翻极限;同时,主动互联抗侧倾控制还能有效改善悬架动挠度及车轮动载,综合提升车辆性能。 展开更多
关键词 液压互联悬架 抗侧倾 主动控制 动器动力 反演法
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分数槽结构悬架直线作动器的性能及其应用 被引量:6
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作者 杨超 李以农 +1 位作者 钟银辉 郑玲 《上海交通大学学报》 EI CAS CSCD 北大核心 2016年第6期837-843,848,共8页
针对电磁主动悬架用直线作动器推力密度低和推力波动大等缺点,提出一种分数槽结构的圆筒形永磁直线作动器,并建立作动器的有限元分析模型,通过理论计算其绕组反电动势验证了其正确性;同时,研究了作动器的作动力、响应时间和效率随速度... 针对电磁主动悬架用直线作动器推力密度低和推力波动大等缺点,提出一种分数槽结构的圆筒形永磁直线作动器,并建立作动器的有限元分析模型,通过理论计算其绕组反电动势验证了其正确性;同时,研究了作动器的作动力、响应时间和效率随速度和电源激励变化的规律.结果表明:作动器绕组的反电动势中含有3、2和4次的谐波分量;作动器作动力存在一定的波动,且随着电流增加而增大;作动器响应时间随着运行速度增加而减小;作动器效率与电压和速度相关,速度越大,效率越高,电压越大,效率越低.根据车辆在各工况下的悬架工作特性得出:当车辆侧倾时,作动器处于低速、大作动力、慢响应、高耗能的工作状态;当随机路面激励时,随着悬架运行速度的提高,应逐渐增大作动器电流激励的幅值和频率. 展开更多
关键词 悬架动器 作动力 响应时间 效率
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基于可控度指标的悬索结构传感器/作动器位置优化研究 被引量:1
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作者 王庆敏 李振涛 +1 位作者 苏木标 杨要恩 《铁道学报》 EI CAS CSCD 北大核心 2012年第5期103-106,共4页
提出一种大跨悬索结构振动主动控制中传感器/作动器位置优化方法。该方法从外部激励和作动力两个角度分析,以加权乘积形式将单位外激励响应、应变能和单位作动力响应三者结合,得到每一个候选单元总可控度指标,该指标最大值处即为传感器... 提出一种大跨悬索结构振动主动控制中传感器/作动器位置优化方法。该方法从外部激励和作动力两个角度分析,以加权乘积形式将单位外激励响应、应变能和单位作动力响应三者结合,得到每一个候选单元总可控度指标,该指标最大值处即为传感器/作动器最佳配制位置。采用所提出理论对悬索结构振动主动控制传感器/作动器位置进行推导,并通过H∞闭环控制理论对所设计最佳位置和一般位置处进行控制仿真分析。结果表明:在单位外激励作用下,一般位置和最佳位置处进行主动控制所需时间分别为4.3s和1.8s,证明了本文位置优化理论的正确性。 展开更多
关键词 应变能 作动力 激励力 传感器/动器
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压电、压磁复合结构的力学作用
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作者 陶玲 关群 《工程与建设》 2007年第6期837-838,845,共3页
嵌入薄板里的压电、压磁片作动器在板内产生作动力,根据变形协调,得出其弯矩推导公式。并对压电、压磁片厚度不同以及嵌入深度不同在板内产生的弯矩值进行比较,得出其作动力大小跟压电、压磁片厚度和嵌入深度有关的结论。
关键词 压电 压磁 叠层板 作动力 横观各向同性
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某导弹折叠弹翼展开过程的仿真分析 被引量:25
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作者 崔二巍 于存贵 +1 位作者 李猛 齐贤伟 《兵工自动化》 2013年第12期12-14,共3页
折叠弹翼的展开性能关系着导弹发射后能否正常飞行。以某导弹的折叠弹翼为研究对象,对其展开过程进行仿真分析。根据其结构和工作原理,在Adams多体动力学软件中建立仿真模型,仿真其在不同作动力曲线下的展开过程,得到弹翼展开角度、角... 折叠弹翼的展开性能关系着导弹发射后能否正常飞行。以某导弹的折叠弹翼为研究对象,对其展开过程进行仿真分析。根据其结构和工作原理,在Adams多体动力学软件中建立仿真模型,仿真其在不同作动力曲线下的展开过程,得到弹翼展开角度、角速度、动能曲线和弹翼与锁定销之间的碰撞力曲线,并对弹翼展开过程中的性能进行检验。仿真结果表明:弹翼能迅速展开到位,并能准确定位、可靠锁定,展开过程中各部件之间不会相互干涉。 展开更多
关键词 折叠弹翼 展开 锁定 作动力 仿真
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固体火箭发动机滚动球窝喷管弹塑性摩擦接触承载性能分析 被引量:2
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作者 刘文芝 李太安 +2 位作者 韦广梅 刘海 赵永忠 《计算力学学报》 CAS CSCD 北大核心 2013年第4期580-586,共7页
固体火箭发动机滚动球窝喷管的弹塑性摩擦接触承载性能,属于复杂结构在复杂载荷作用下的弹塑性摩擦接触问题,它直接决定着系统的结构设计和功能发挥。为保证系统在承受极端工作载荷时,喷管不产生大的轴向位移,阴球、阳球与滚动体间具有... 固体火箭发动机滚动球窝喷管的弹塑性摩擦接触承载性能,属于复杂结构在复杂载荷作用下的弹塑性摩擦接触问题,它直接决定着系统的结构设计和功能发挥。为保证系统在承受极端工作载荷时,喷管不产生大的轴向位移,阴球、阳球与滚动体间具有一定的接触强度,同时不产生过量的塑性变形,设计阶段,基于计算精度高的三维摩擦接触问题的Lagrange乘子法,解决了与弹塑性耦合的算法问题;在滚动体运动分析及摩擦测试的基础上,模拟系统冷试车冲压试验,充分考虑材料表面强化层,建立了各构件间的弹塑性摩擦接触模型。有限元计算结果及冷试车分解试验、系统作动力矩测试试验结果表明,系统弹塑性摩擦接触承载性能满足结构设计要求,有限元建模及计算结果正确。 展开更多
关键词 固体火箭 滚动球窝喷管 弹塑性摩擦接触承载性能 冷试车分解试验 作动力
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非线性主动悬架backstepping控制研究 被引量:6
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作者 邱香 《华东交通大学学报》 2016年第3期54-59,共6页
主动悬架控制系统中减振器阻尼为非线性,采用经典控制方法需要将其线性化,这使得控制模型与实际之间有误差。根据某减振器测试的阻尼特性,将其分段拟合,还原其非线性特性,同时考虑液压作动器动力学特性,建立了1/4悬架动力学模型;采用bac... 主动悬架控制系统中减振器阻尼为非线性,采用经典控制方法需要将其线性化,这使得控制模型与实际之间有误差。根据某减振器测试的阻尼特性,将其分段拟合,还原其非线性特性,同时考虑液压作动器动力学特性,建立了1/4悬架动力学模型;采用backstepping非线性控制方法,完成了控制器设计及稳定性分析,结合某车参数,对控制系统进行了多种路面工况输入下的仿真,结果表明,采用非线性控制方法在兼顾悬架动挠度及车轮动载时,可有效改善车身加速度,提高舒适性。 展开更多
关键词 非线性阻尼 动器动力 主动悬架 BACKSTEPPING
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Computation of Ship Hydrodynamic Interaction Forces in Restricted Waters using Potential Theory 被引量:8
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作者 Xueqian Zhou Serge Sutulo C. Guedes Soares 《Journal of Marine Science and Application》 2012年第3期265-275,共11页
A computer code based on the double-body potential flow model and the classic source panel method has been developed to study various problems of hydrodynamic interaction between ships and other objects with solid bou... A computer code based on the double-body potential flow model and the classic source panel method has been developed to study various problems of hydrodynamic interaction between ships and other objects with solid boundaries including the seabed. A peculiarity of the proposed implementation is the application of the so-called "moving-patch" method for simulating steady boundaries of large extensions. The method is based on an assumption that at any moment just the part of the boundary ("moving patch") which lies close to the interacting ship is significant for the near-field interaction. For a specific case of the fiat bottom, comparative computations were performed to determine optimal dimensions of the patch and of the constituting panels based on the trade-off between acceptable accuracy and reasonable efficiency. The method was applied to estimate the sway force on a ship hull moving obliquely across a dredged channel. The method was validated for a case of ship-to-ship interaction when tank data were available. This study also contains a description of a newly developed spline approximation algorithm necessary for creating consistent discretizations of ship hulls with various degrees of refinement. 展开更多
关键词 ship hydrodynamic interaction restricted waters moving panelled patch method potential theory
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Research and Design of Coordinated Control Strategy for Smart Electromechanical Actuator System 被引量:2
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作者 HAO Zhenyang ZHANG Qiyao +2 位作者 CHEN Huajie CAO Xin MIAO Wei 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2022年第5期507-520,共14页
In order to improve the frequency response and anti-interference characteristics of the smart electromechanical actuator(EMA)system,and aiming at the force fighting problem when multiple actuators work synchronously,a... In order to improve the frequency response and anti-interference characteristics of the smart electromechanical actuator(EMA)system,and aiming at the force fighting problem when multiple actuators work synchronously,a multi input multi output(MIMO)position difference cross coupling control coordinated strategy based on double‑closed-loop load feedforward control is proposed and designed.In this strategy,the singular value method of return difference matrix is used to design the parameter range that meets the requirements of system stability margin,and the sensitivity function and the H_(∞)norm theory are used to design and determine the optimal solution in the obtained parameter stability region,so that the multi actuator system has excellent synchronization,stability and anti-interference.At the same time,the mathematical model of the integrated smart EMA system is established.According to the requirements of point-to-point control,the controller of double-loop control and load feedforward compensation is determined and designed to improve the frequency response and anti-interference ability of single actuator.Finally,the 270 V high-voltage smart EMA system experimental platform is built,and the frequency response,load feedforward compensation and coordinated control experiments are carried out to verify the correctness of the position difference cross coupling control strategy and the rationality of the parameter design,so that the system can reach the servo control indexes of bandwidth 6 Hz,the maximum output force 20000 N and the synchronization error≤0.1 mm,which effectively solves the problem of force fighting. 展开更多
关键词 smart electromechanical actuator(EMA) force fighting coordinated control strategy cross coupling control singular value method of return difference matrix sensitivity H∞norm control
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Dynamic Interaction of Soil-Isolated Structure:A Systematic Review 被引量:3
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作者 YU Xu WU Xiaofei +1 位作者 ZHU Mingxuan ZHUANG Haiyang 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2020年第1期40-53,共14页
Isolation technique of ground structure is a hot topic in the field of earthquake engineering and structure dynamics.Since soil-isolated structure dynamic interaction study is of great significance to enhance seismic ... Isolation technique of ground structure is a hot topic in the field of earthquake engineering and structure dynamics.Since soil-isolated structure dynamic interaction study is of great significance to enhance seismic performance of isolated structures and revision of relevant isolation specifications,research on dynamic interaction of soil-isolated structure has attracted more and more attention.Based on the basic theory of soil-structure dynamic interaction,we summarize and analyze the research status quo of soil-isolated structure dynamic interaction by means of theoretical analysis,numerical simulation,model test,prototype observation and seismic performance.After reviewing the results of previous research,we reveal that some key issues,which can be used to uncover dynamic interaction mechanism and seismic response characteristics of soil-isolated structures interaction system,should not be neglected.Based on the concept of seismic performance design and the latest research of soil-isolated structure dynamic interaction,we predict the future development of soil-isolated structure dynamic interaction by elastoplastic time history analysis method,seismic performance level and practical analysis method based on energy. 展开更多
关键词 isolated structure earthquake resistance soil-structure interaction
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Computational Study on Interaction Between Swimming Fish and Drifting Vortices Behind the Cylinder 被引量:1
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作者 TONG Ying XIA Jian +1 位作者 CHEN Long XUE Haotian 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2022年第1期108-120,共13页
To predict the flow evolution of fish swimming problems,a flow solver based on the immersed boundary lattice Boltzmann method is developed.A flexible iterative algorithm based on the framework of implicit boundary for... To predict the flow evolution of fish swimming problems,a flow solver based on the immersed boundary lattice Boltzmann method is developed.A flexible iterative algorithm based on the framework of implicit boundary force correction is used to save the computational cost and memory,and the momentum forcing is described by a simple direct force formula without complicated integral calculation when the velocity correction at the boundary node is determined.With the presented flow solver,the hydrodynamic interaction between the fish-induced dynamic stall vortices and the incoming vortices in unsteady flow is analyzed.Numerical simulation results unveil the mechanism of fish exploiting vortices to enhance their own hydrodynamic performances.The superior swimming performances originate from the relative movement between the“merged vortex”and the locomotion of the fishtail,which is controlled by the phase difference.Formation conditions of the“merged vortex”become the key factor for fish to exploit vortices to improve their swimming performance.We further discuss the effect of the principal components of locomotion.From the results,we conclude that lateral translation plays a crucial role in propulsion while body undulation in tandem with rotation and head motion reduce the locomotor cost. 展开更多
关键词 immerse boundary lattice Boltzmann method complex deformable boundary fluid-fish interaction hydrodynamic mechanism bionic propulsion
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A CFD Based Investigation of the Unsteady Hydrodynamic Coefficients of 3-D Fins in Viscous Flow 被引量:3
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作者 Nazir Zulfiqar 苏玉民 王兆立 《Journal of Marine Science and Application》 2010年第3期250-255,共6页
The motion of the fins and control surfaces of underwater vehicles in a fluid is an interesting and challenging research subject.Typically the effect of fin oscillations on the fluid flow around such a body is highly ... The motion of the fins and control surfaces of underwater vehicles in a fluid is an interesting and challenging research subject.Typically the effect of fin oscillations on the fluid flow around such a body is highly unsteady, generating vortices and requiring detailed analysis of fluid-structure interactions.An understanding of the complexities of such flows is of interest to engineers developing vehicles capable of high dynamic performance in their propulsion and maneuvering.In the present study, a CFD based RANS simulation of a 3-D fin body moving in a viscous fluid was developed.It investigated hydrodynamic performance by evaluating the hydrodynamic coefficients (lift, drag and moment) at two different oscillating frequencies.A parametric analysis of the factors that affect the hydrodynamic performance of the fin body was done, along with a comparison of results from experiments.The results of the simulation were found in close agreement with experimental results and this validated the simulation as an effective tool for evaluation of the unsteady hydrodynamic coefficients of 3-D fins.This work can be further be used for analysis of the stability and maneuverability of fin actuated underwater vehicles. 展开更多
关键词 oscillating 3-D fin RANS hydrodynamic performance viscous flow
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Physical simulation of hydrodynamic conditions in high rank coalbed methane reservoir formation 被引量:5
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作者 WANG Bo JIANG Bo +5 位作者 LIU Lei ZHENG Gui-qiang QIN Yong WANG Hong-yan LIU Hong-lin LI Gui-zhong 《Mining Science and Technology》 EI CAS 2009年第4期435-440,共6页
In order to select highly productive and enriched areas of high rank coalbed methane reservoirs, based on hydrologic geology as one of the main factors controlling coalbed methane (CBM) reservoir formations, the eff... In order to select highly productive and enriched areas of high rank coalbed methane reservoirs, based on hydrologic geology as one of the main factors controlling coalbed methane (CBM) reservoir formations, the effect of hydrodynamic forces controlling CBM reservoir formations was studied by a physical simulation experiment in which we used CBM reservoir simulation facilities. The hydrodynamic conditions of high coal rank reservoirs in the Qinshui basin were analyzed. Our experiment shows the following results: under strong hydrodynamic alternating action, 6C~ of coalbed methane reservoir changed from the start at -2.95% ~ -3.66%, and the lightening process occurred in phases; the CI-I4 volume reduced from 96.35% to 12.42%; the CO2 vo- lume decreased from 0.75% in sample 1 to 0.68% in sample 2, then rose to 1.13% in sample 3; the N2 volume changed from 2.9% in sample 1 to 86.45% in sample 3. On one hand, these changes show the complexity of CBM reservoir formation; on the other hand, they indicate that strong hydrodynamic actions have an unfavorable impact on CBM reservoir formation. It was found that the gas volume and hydrodynamic intensity were negatively correlated and low hydrodynamic flow conditions might result in highly productive and enriched areas of high rank CBM. 展开更多
关键词 high coal rank coalbed methane reservoir hydrodynamic condition physical simulation Qinshui basin
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Dynamic action simulation system and preliminary experiments of coal seams and gas 被引量:4
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作者 LI Jian-lou YAN Jia-ping +2 位作者 XIE Yan CHEN Ping WANG Lai-bin 《Mining Science and Technology》 EI CAS 2009年第4期473-478,共6页
In order to study the dynamic action and physical effects of coal seams and gas, a simulation system for this dynamic action was developed and a physical model built in our laboratory. Using this newly built model, th... In order to study the dynamic action and physical effects of coal seams and gas, a simulation system for this dynamic action was developed and a physical model built in our laboratory. Using this newly built model, the volume of coal outbursts and the temperature during the outburst process were studied. The results show that: l) for coal seams with similar structure and com- ponents, two factors, i.e., gas pressure and ground stress affect the volume of coal outbursts, with gas pressure being the more im- portant of the two and 2) the changes in coal temperature, both its increase and decrease, are affected by ground stress and gas pressure, it is a process of change. Preliminary tests show that the system can simulate the dynamic interaction of coal and gas, which is helpful for studying the dynamic mechanism of solid-gas coupling of gas and coal. 展开更多
关键词 GAS dynamic action simulation system TEMPERATURE
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Dynamic Interaction of Parallel Moving Ships in Close Proximity 被引量:2
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作者 M. Rafiqul Islam Motohiko Murai 《Journal of Marine Science and Application》 2013年第3期261-271,共11页
Nowadays,there are many studies conducted in the field of marine hydrodynamics which focus on two vessels traveling and floating in sufficiently close proximity to experience significant interactions.The hydrodynamic ... Nowadays,there are many studies conducted in the field of marine hydrodynamics which focus on two vessels traveling and floating in sufficiently close proximity to experience significant interactions.The hydrodynamic behavior of parallel moving ships in waves is an interesting and important topic of late.A numerical investigation has been carried out for the prediction of wave exciting forces and motion responses of parallel moving ships in regular waves.The numerical solution was based on 3D distribution technique and using the linear wave theory to determine the exciting forces and ship's motion.The speed effects have been considered in the Green function for more realistic results.The numerical computations of wave exciting forces and motion responses were carried out for a Mariner and Series 60 for the purpose of discovering different Froude numbers and different separation distances in head sea conditions.Based on the numerical computations,it was revealed that the sway,roll and yaw have a significant effect due to hydrodynamic interaction. 展开更多
关键词 3D source distribution dynamic interaction close proximity parallel moving ships ship motion
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A Coupled Analysis of Nonlinear Sloshing and Ship Motion 被引量:4
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作者 Shuo Huang Wenyang Duan Hao Zhang 《Journal of Marine Science and Application》 2012年第4期427-436,共10页
Nonlinear interactions among incident wave, tank-sloshing and floating body coupling motion are investigated. The fully nonlinear sloshing and body-surface nonlinear free surface hydrodynamics is simulated using a Non... Nonlinear interactions among incident wave, tank-sloshing and floating body coupling motion are investigated. The fully nonlinear sloshing and body-surface nonlinear free surface hydrodynamics is simulated using a Non-Uniform Rational B-Spline (NURBS) higher-order panel method in time domain based on the potential theory. A robust and stable improved iterative procedure (Yan and Ma, 2007) for floating bodies is used for calculating the time derivative of velocity potential and floating body motion. An energy dissipation condition based on linear theory adopted by Huang (2011) is developed to consider flow viscosity effects of sloshing flow in nonlinear model. A two-dimensional tank model test was performed to identify its validity. The present nonlinear coupling sway motion results are subsequently compared with the corresponding Rognebakke and Faltinsen (2003)'s experimental results, showing fair agreement. Thus, the numerical approach presented in this paper is expected to be very efficient and realistic in evaluating the coupling effects of nonlinear sloshing and body motion. 展开更多
关键词 NONLINEAR tank-sloshing coupling motion energy dissipation
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Huge thick conglomerate movement induced by full thick longwall mining huge thick coal seam 被引量:7
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作者 Ma Liqiang Qiu xiaoxiang +2 位作者 Dong Tao Zhang Jixiong Huang Yanli 《International Journal of Mining Science and Technology》 SCIE EI 2012年第3期399-404,共6页
A discrete elemental method was used to study the thickness of conglomerate layer in a full thick seam mining activities under the influence of the law, pointing out the thickness of the conglomerate at different seam... A discrete elemental method was used to study the thickness of conglomerate layer in a full thick seam mining activities under the influence of the law, pointing out the thickness of the conglomerate at different seam mining, and during the destruction and instability of existing state of laws. At 21141 thick seam mining, the face toward the direction of separation between the thick layer of conglomerate rock and the next bit after reaching its maximum capacity due to pull from the bottom of the plastic zone, formed a stratified and hierarchical down collapse. The shape of caving area is a ''triangular block'', the length of the plastic zone and face advancement from the linear fit between the height of the plastic zone and the advancing face is a quadratic function of distance, while the top layer of thick gravel layer is the overall bending subsidence trend. Tilting the direction of the face, a thick gob of collapsed conglomerate layer is formed in the coal gob entity on both sides of the thick conglomerate at the top of the overall fracture morphology performance, thus forming a mutual extrusion of articulated block structure. The instability, separation and balance of the thick conglomerate layer in the hinged block stope stress leads to abnormal occurrence of rock burst induced by face as the major factor in the accident. This research reveals the form of stress distribution in the destroyed layer of the thick conglomerate rock, analyzes the stope law of coupling for the pressure burst behavior law for the mining work face, and the choice of preventive measures to provide a theoretical basis and implementation. 展开更多
关键词 Huge thick conglomerateHuge thick coal seamSeparationCollapseRock burst
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Numerical Investigation of Hydrodynamic Flow Over an AUV Moving in the Water-surface Vicinity Considering the Laminar-turbulent Transition 被引量:3
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作者 Mahmoud Salari Amin Rava 《Journal of Marine Science and Application》 CSCD 2017年第3期298-304,共7页
Nowadays, Autonomous Underwater Vehicles(AUVs) are frequently used for exploring the oceans. The hydrodynamics of AUVs moving in the vicinity of the water surface are significantly different at higher depths. In this ... Nowadays, Autonomous Underwater Vehicles(AUVs) are frequently used for exploring the oceans. The hydrodynamics of AUVs moving in the vicinity of the water surface are significantly different at higher depths. In this paper, the hydrodynamic coefficients of an AUV in non-dimensional depths of 0.75, 1, 1.5, 2, and 4D are obtained for movement close to the free-surface. Reynolds Averaged Navier Stokes Equations(RANS) are discretized using the finite volume approach and the water-surface effects modeled using the Volume of Fraction(VOF) method. As the operating speeds of AUVs are usually low, the boundary layer over them is not fully laminar or fully turbulent, so the effect of boundary layer transition from laminar to turbulent flow was considered in the simulations. Two different turbulence/transition models were used: 1) a full-turbulence model, the k-ε model, and 2) a turbulence/transition model, Menter's Transition-SST model. The results show that the Menter's Transition-SST model has a better consistency with experimental results. In addition, the wave-making effects of these bodies are studied at different immersion depths in the sea-surface vicinity or at finite depths. It is observed that the relevant pitch moments and lift coefficients are non-zero for these axi-symmetric bodies when they move close to the sea-surface. This is not expected for greater depths. 展开更多
关键词 autonomous underwater vehicles sea surface effects computational fluid dynamics HYDRODYNAMICS laminar to turbulent transition
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Numerical Simulation of Motion Response of an Offshore Observation Platform in Waves 被引量:8
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作者 Yuanchuan Liu Decheng Wan 《Journal of Marine Science and Application》 2013年第1期89-97,共9页
Offshore observation platforms are required to have great ability to resist waves when they are operating at sea. Investigation on the motion characteristics of the platforms in the sea can provide significant referen... Offshore observation platforms are required to have great ability to resist waves when they are operating at sea. Investigation on the motion characteristics of the platforms in the sea can provide significant reference values during the platform design procedure. In this paper, a series of numerical simulation on the interaction of a triple-hulled offshore observation platform with different incident waves is carried out. All of the simulations are implemented utilizing our own solver naoe-FOAM-SJTU, which is based and developed on the open source tools of OpenFOAM. Duration curves of motion characteristics and loads acting on the platform are obtained, and a comparison between the results of the amplitude in different incident waves is presented. The results show that the solver is competent in the simulation of motion response of platforms in waves. 展开更多
关键词 offshore observation platform motion characteristics naoe-FOAM-SJTU solver finite volume method (FVM) pressure-implicit-split-operator (PISO)
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