Numerical Simulation of Viscous Flow Around a Rolling Cylinder with Ship-Like Section

Two-dimensional unsteady incompressible viscous flow around a rolling cylinder with ship-like section is numerically simulated by employing the computational scheme previously developed by the authors, in which the continuity and momentum equations are satisfied simultaneously at each time step for oscillating flow. The numerical results show that the motion of vortices around a rolling ship hull is cyclical. It is found that the location of the vortices is very similar to the existing experimental result. Using these simulation results, we can calculate the roll damping of ships including viscous effects.

Calculating the Wave Force on Partially Immersed Large-Scale Horizontal Cylinders

Large-scale interceptors constitute the main structure of offshore self-driven floating marine litter collection devices,and the structural stability of such interceptors under the action of waves directly influences the overall safety of the device.When the ratio of the diameter of a horizontal cylinder in such interceptors to the incident wavelength is larger than 0.25,the wave force can be calculated by using the diffraction theory,by considering the problem as that of the interaction between the waves and a partially immersed large-scale horizontal cylinder.In this study,an analytical approach to calculate the wave force on a partially immersed large-scale horizontal cylinder was formulated by using the stepwise approximation method.Physical model tests were conducted to investigate the effects of different factors(wave height,period,and immersion depth)on the wave force on a large-scale horizontal cylinder under conditions involving short-period waves.The results show that both horizontal and vertical wave forces on the cylinder increase as the wave height(immersion depth)increases in most cases.The vertical wave force decreases with the decrease of the period.For the horizontal wave force,it increases with the decrease of the period when the wavelength is larger than the diameter of the cylinder and decreases with the decrease of the period when the wavelength is smaller than the diameter of the cylinder.

Theoretical and Practical Studies of Determining the Force of the Lifting-Lowering of the Roll Box

The lifting and lowering mechanism of the roll box of the saw gin, being an integral part of the ginning process, is used when starting the electric motor of the saw cylinder until its rated speed is reached to prevent an increase in the load current on it, as well as to start the ginning process. The article defines the kinematics of the movement, and also studies the regularity of the movement of the roll box of the saw gin when lifting it with the help of a pneumatic drive. The kinematics of the roll box movement was determined through experimental studies. Knowing the equation of motion, using the second-order Lagrange equation, the regularity of the change in the lifting force of the roll box was determined. Here the system is closed, its degree of freedom is equal to one. The angle of rotation of the roll box is taken as a generalized coordinate. Numerical results were obtained using the Matlab software environment. The theoretical analysis and graphs for determining the lifting force of the roll box are presented. To study the kinematics of lifting the roll box, a method and a test bench have been developed. According to him, when the roll box was raised, its movement was recorded on video, the image was processed using the After Effect and CorelDraw programs, and the movement of the rod attachment point to the roll box was determined. And also the equation for changing the angle of rotation of the roll box is determined using the Matlab Curve Fiting program.

R1轧机新增AGC油缸控制系统的研究与应用

介绍了热轧1580产线R1轧机新增AGC油缸控制系统,使得轧机刚度可以通过标定检测,掌控轧机状态;AGC响应速度快,轧机调平精度高,有利于改善R1轧机板形,对后续R2轧机和精轧机的轧制稳定性,板形控制、产品质量都大有改善。

吴江卷曲式人行开启桥设计

吴江卷曲式人行开启桥项目位于吴江区东部两省一市交界区域,是规划水乡市集节点水上活动中心游艇进出元荡湖的主要出口,对景观要求高,要求修建一座标志性建筑的景观人行桥,该桥同时有开启要求,综合考虑多种因素,最终采用卷曲式人行开启桥方案。介绍了该卷曲式开启桥的特殊地理位置、方案构思、通航条件、总体设计、结构设计、液压设计、开启顺序等。通过研究,该工程达到了预期的景观和开启性能目标,具体分析方法和结论可供同类工程参考。

某热轧大型非标伺服液压缸故障分析及改进

对某钢铁企业热轧轧机的大型非标伺服液压缸的故障进行了分析和改进方案研究。通过对液压缸进行拆解与详细检查,确定了故障产生的原因,再根据有限元分析以及现场实际情况制定对应的改进方案。液压缸经改进后,工作状态得到了显著改善,稳定性和可靠性均得到提升,为冶金行业中大型非标伺服液压缸的故障分析与改进提供了参考,具有一定的理论和实践指导意义。

油缸内孔刮滚加工刀具的优化

刮滚加工是油缸内孔精加工常用的一种方法,通过一次装卡,完成内孔粗镗、刮削、滚压3道工序,粗镗头包含位于同一圆周面上的4个镗刀片,用于切除缸筒内孔的大部分余量。现用TGK53刮滚机粗镗时刀片切削刃有效切削长度较短,刀片易受热损坏、寿命较低;刀片主偏角75°,向前镗孔时径向分力较大,造成刀具或缸筒震动,加工质量无法保证。通过选择高寿命刀片、调整切削角度、优化刀夹结构、改善切削参数,提高刀具寿命、加工效率以及产品尺寸精度。

微型无油滚动转子压缩机的动力特性与摩擦损失分析

微型滚动转子压缩机的无油化带来的摩擦损耗问题不容忽视,研究其摩擦损耗分布规律及其改进措施对提高压缩机效率至关重要,为此,对微型无油滚动转子压缩机主要摩擦副进行了变工况、变结构的摩擦功耗研究。首先,建立了微型无油滚动转子压缩机动力学分析的数学模型;然后,对微型无油滚动转子压缩机主要部件的受力进行了特性分析,并计算获得了主要摩擦副摩擦功耗随主轴转角的变化规律;最后,分析了排气压力、滑片厚度、偏心率和相对气缸长度对微型无油滚动转子压缩机主要摩擦副摩擦功耗及其占比的影响规律。研究结果表明:排气压力从1100 kPa提高至1800 kPa,压缩机总摩擦功耗升高了67.7%;滑片厚度从1 mm提高至3 mm,总摩擦功耗仅升高了32.8%;偏心率从0.06提高至0.2,总摩擦功耗升高了121.5%;相对气缸长度从0.25提高至0.6,总摩擦功耗升高了31.9%。根据分析结果可得出结论:微型无油滚动转子压缩机的偏心率的取值在0.14左右最为合适,优化偏心率对改善微型无油滚动转子压缩机的摩擦损失效果最明显,其次是改变滑片厚度,最后是改变相对气缸长度。

液压油缸内孔滚压加工装置

液压油缸是液压机设备的核心部件,油缸体内孔表面的粗糙度和硬度是关键。本文介绍了一种油缸体内孔加工装置,可以提高油缸体内孔表面粗糙度及其表面硬度,克服传统加工装置结构的缺点,解决液压油缸常规加工工艺中遇到的问题,节约成本,提高效率。

Design of a high-precision twin-roll strip caster

During strip casting,the thickness deviation of casting strip directly affects the quality of the hot-rolled sheet because the casting strip needs to be rolled only once.To accurately control the gap between casting rolls and reduce the thickness deviation of the casting strip,a conceptual design of a prestressed twin-roll caster is proposed herein;this caster involves the setting of a constant pressure balancing cylinder between the chocks of two casting rolls.The balancing cylinder hydraulic system adopts a three-way servo valve that controls the hydraulic cylinder.The parameters of the hydraulic power components are determined using the principle of optimal power matching,and the hydraulic system model of the balancing cylinder is thus established.The dynamic analysis and simulation of the hydraulic system are performed using finite element model to obtain relevant evaluation indexes.Finally,the hydraulic system is corrected using proportional-integral-derivative (PID) correction to achieve a well-controlled effect.Thus,the engineering requirements of the strip casting process can be met.

面向航空航天的薄壁锥形筒件轧制成形过程几何状态综合控制方法

针对航空航天薄壁锥形筒件轧制过程几何变形状态难以控制的问题,研究了薄壁锥形筒件轴线偏移、轴线倾斜、小端拉缩三种典型异常变形状态及形成机理,提出了基于筒件线速度反馈的锥辊运动协调控制方法,建立了锥形筒件轧制过程锥辊运动控制模型;提出了薄壁锥形筒件坯料优化设计方法,并建立了相应的芯辊倾斜进给控制策略,保证了锥形筒件直径长大速度的一致性,消除了因金属轴向和周向流动不匹配导致的小端拉缩现象;基于ABAQUS软件和VUAMP子程序开发,建立了集成所提控制方法和策略的薄壁锥形筒件轧制有限元模型。对比分析了常规规划控制、上述方法独立控制和综合控制下的筒件轧制成形效果,结果表明,综合控制方法下的轴线偏移量、圆度误差、同心度误差和倾斜角误差等指标相比于常规规划控制在整圆阶段内分别降低了93.6%、75.3%、95.1%、97.2%。

轧机AGC液压缸智能检测系统平台研发

针对轧机AGC液压缸静动态特性性能指标测试技术第三方验证的重要性,开发一套人机交互式AGC液压缸试验台检测系统,采用厂级ERP企业管理系统,实时远程控制与测试,实现第三方与生产厂家的轧机AGC液压缸性能指标测试数据的检定、校准工作与报告生成。结果表明:该系统平台可有效提高轧机AGC液压缸性能指标测试数据准确性,测试功能满足第三方需求。

Z-High连轧机窜辊缸底座优化的研究及应用

针对RAP线Z-High连轧机原设计的本身缺陷而造成五个机架出现窜辊缸底座螺丝断裂、影响设备稳定运行、轧制功能精度严重不足、引发大量不合卷及长时间故障停车的问题。通过对机架窜辊缸底座结构进行优化改进,利用在线加工技术,对薄弱部位进行优化处理,彻底解决了螺丝断裂的问题,极大地保证了机组的稳定运行。

1580线精轧机工作辊平衡缸快速更换法

1580线精轧机工作辊平衡缸工作环境比较恶劣,在线使用寿命不到2年,检修更换难度较大。针对此问题,对其移动块本体结构进行了改造,并研究了平衡杠快速更换方法,从而降低了员工劳动强度,提高了作业效率,提高了安全系数,降低了安全风险。

基于Ansys的锂电池极片辊压质量改善研究

目的优化辊压机结构,减小辊压后极片的不均匀性,进一步提升锂电池性能。方法首先,将辊压机工程模型简化为仿真模型,运用Hypermesh对仿真模型进行网格划分,重点加密极片和轧辊接触区域的网格,将划分好的网格以Inp格式导入Ansys中,设置边界条件并求解计算,模拟轧辊辊压极片的过程。其次,提取极片监测点的仿真数据,换算得到极片辊压后的厚度,将仿真结果与实验数据对比,验证极片辊压仿真方法的准确性。最后,运用该仿真方法分析液压弯缸力、弧形辊弓高和轧辊辊面长度等对极片辊压质量的影响。结果分析仿真和实验结果可知,辊压后极片的厚度平均值和极差值对标率均在90%以上,证明了仿真方法准确可靠。随着弯缸力(0~784000 N)逐渐增大,极片厚度极差值先减小后增大;随着弧形辊弓高(0~60μm)逐渐增大,极片厚度极差值先减小后增大;随着轧辊辊面长度(1200~1500mm)逐渐减小,极片厚度极差值逐渐减小。结论施加合适的弯缸力、对弧形辊进行设计均可改善极片辊压质量。轧辊辊面长度越小,极片辊压效果越好。可通过极片辊压仿真方法确定最优弯缸力大小与弧形辊最优弓高,该方法大幅度缩短了辊压机研发周期,优化了辊压机性能,提高了极片辊压质量,为锂电池性能的提升奠定了基础。

侧倾翻试验台的总体设计及多液压缸同步性研究

侧倾翻试验台是检测农业机械、汽车、挂车等机动车稳定性的关键设备。为满足相关试验标准要求,开发了一种大型双台面侧倾翻试验台。本文介绍了该设备的总体设计思路。为解决试验台多液压油缸同步控制的难题,研制一套跟踪调节快速、反应速度快、柔性好的多液压油缸同步控制系统,以LabVIEW和PLC为控制核心,能很好地满足试验台多液压油缸同步的需要,并在现场试验中得到验证。

完井管串密封筒镗滚加工研究及应用

为了满足海上不同井况和完井方式下分层注采和细分层系的作业需要,采用多组密封筒进行层间封隔。然而,密封筒在完井和后期修井过程中需要频繁通过油管和往复插入密封工具,常规珩磨加工成形内孔密封面的综合耐磨能力低、配合密封可靠性不足。因此,创新采用了一种适用于完井管柱系列密封筒精镗和滚压一体加工方法,同时对不同规格、材质的密封筒滚压量参数进行了优化研究。2016年至今,已在渤海油田累计应用了250余个滚压成形密封筒,其中注水井动管柱插拔洗井每年平均2次且层间验封合格。结果表明,滚压加工密封筒技术提高了密封筒往复通过工具的耐磨性和配合密封的可靠性,为海上油田增产增注提供了技术支撑。

冷轧机重要零部件的改进及性能验证

针对当前冷轧机组生产的关键零部件存在缺陷而导致产品质量和精度不满足要求的问题,在对冷轧机组现状进行综合分析的基础上,重点对弯辊缸、熨平辊以及助卷器进行改进,并对改进后的效果进行了综合评估,达到了预期的效果。

技术改进的密封端盖对线轧机工作性能的提升

针对2号RAP线轧机的工作辊提升臂液压缸经常发生泄漏造成故障停车和质量卷的问题,在一定研究成果和研究思路的基础上,结合2号RAP线轧机的工作运行性能,对其液压缸的密封端盖进行技术改进。对密封端盖从密封材质和密封结构上进行改进之后,通过运行记录对其改进效果进行了验证,并对技术改进的密封端盖进行经济效益的评估。

75MN筒节轧机电气控制系统研究与应用

筒节轧机采用轧制方式加工大型筒节,较传统锻造方式,提高了生产效率,大大降低了筒节原材料的消耗。根据筒节轧机设备及工艺需要采用传动及自动化两级控制系统的设计方案。筒节轧机的主传动选用中压交直交变频器,基础自动化系统的控制器采用PLC,现场总线选用PROFIBUS-DP现场总线。设置一套HMI监控系统用于完成筒节轧机运行状况的监视、参数设定、轧制程序输入、IO信号状态显示、故障分析及故障报警信息显示及记录。筒节轧机电气控制系统完成了主传动控制、筒节上料卸料控制、抱辊力控及同步控制、筒节跑偏控制、筒节矫圆控制及筒节轧制控制等控制功能,为筒节轧机的正常运行提供了强有力的保障。