大型抓斗卸船机起升系统钢丝绳工作特性研究

卸船机传动系统在变速变载的复杂工况下,将产生较大的动载荷并传递给钢丝绳,产生振动与疲劳.通过分析2 250 t.h-1大型抓斗卸船机传动系统的工作原理,建立起升、开闭钢丝绳的载荷谱和受力模型,并建立了钢丝绳的有限元模型,分析了钢丝绳在最大载荷作用下的静力学特性和开闭工况下动态响应,得到了钢丝绳在工作状态的应力与变形规律,为卸船机的使用、保养和维护提供了参考.     

擦窗机钢丝绳在特殊工况下动载荷分析

以擦窗机提升钢丝绳为研究对象,基于机械振动理论,建立了擦窗机吊重悬空静止时突然起升、吊重匀速下降时突然制动、吊重被突然提升离地三种工况的动力学模型。通过MATLAB软件仿真出不同工况下钢丝绳动载荷随时间变化的关系。以钢丝绳的刚度和结构阻尼比为变量,研究其对钢丝绳动载荷的影响。结果表明,选用刚度较大的钢丝绳能够有效缩减振动系统的震荡时间,对钢丝绳所受的最大动载荷值影响甚微。随着钢丝绳的阻尼比增大,能够有效地减小钢丝绳震荡的稳定时间和钢丝绳所受最大动载荷。为擦窗机结构设计和动态特性优化提供理论参考。     

细钢丝绳张力在线检测装置的研制

采用“三点弯曲法”测力原理,设计出了以单片机为控制核心的细钢丝绳张力在线检测装置。该装置可以夹持于钢丝绳的任何位置,测出本身运动或不运动的钢丝绳的静、动张力。     

悬索长度计算在起重机钢丝绳中的应用

在不考虑悬索弹性变形的前提下,运用悬索的悬垂模型计算悬索实际长度,并将此法应用到单臂架类门座起重机钢丝绳悬垂度计算中,解释钢丝绳因受自身重力作用下垂,使钢丝绳垂落至臂架上,以及出现吊具在空载下放时不下降的现象。借助自编程序对不同水平跨度、不同支点水平倾角、不同钢丝绳线密度及不同倍率的绕绳滑轮组进行分析计算,得出钢丝绳悬垂度与吊具重量、滑轮组2支点相对位置及滑轮组倍率的关系,并可准确计算钢丝绳悬垂度、给定钢丝绳最大允许悬垂度条件下的吊具临界重量及起重机在放绳过程中卷筒放绳长度与吊具实际下降高度差,对指导吊具设计,特别是对吊具重量控制有一定的现实意义。     

A linear viscoelastic relaxation-contact model of a flat fractal surface: a Maxwell-type medium

In this paper a hybrid virtual prototype is developed for analyzing the stress applied on cable shovel components by integrating flexible bodies into rigid multi-body model. The general mechanical system of the cable shovel is modeled as a seven-bar linkage with four degrees of freedom. The relevant theories applied for the dynamic model are described in terms of Lagrangian dynamics equation. The flexible body stress related to the body deformation is obtained by the dynamic equilibrium equation for a structural component based on the finite element method. A P&H 4100A cable shovel is used to validate the hybrid virtual prototype by loading the motions and loads on the model. Von Mises stress distributions of the boom, handle, hoist rope and sheave are visualized during cable shovel operation 3 sec. The results show that a high stress field is around the hoist rope. The maximum stress of 313.31 MPa occurs at node 441. By comparing the simulation results with reliability analysis results, the former is found to match well with the latter. Attention of this study is devoted to the mechanisms of damage of the cable shovel and also the critical high stress areas.     

斜井提升系统动力学计算及跑车防护问题探讨

矿井提升过程中松绳、断绳的事故时有发生,文中建立了斜井提升系统矿车卡住时的动力学模型,研究了斜井提升矿车卡住和紧急制动松绳时的钢丝绳动力学特性,对跑车防护问题进行了探讨和分析。     

基于钢丝绳股绳张力在线自动检测技术

根据三点弯曲法原理设计钢丝绳股绳张力测定传感器,通过微处理机检测多股钢丝绳张力大小,成功实现了钢丝绳股绳张力在线自动检测。现场试验结果表明:该检测系统工作性能稳定可靠。     

基于多频带谱熵的水平气液两相流结构复杂性分析

针对传统功率谱熵只能刻画总体系统结构复杂性问题,提出既能从宏观角度又能从微观角度反映系统结构复杂性的多频带谱熵的分析方法。分析几种典型信号的多频带谱熵特征,验证多频带谱熵方法的可行性及抗干扰能力;利用环形电导传感器阵列获取动态实验测试数据,计算水平气液两相流波状流、塞状流和弹状流含水率波动的多频带谱熵值,分析3种流型结构复杂性随频带因子变化的演变规律。实验结果表明:波状流的多频带谱熵最低,弹状流多频带谱熵值最高;塞状流的多频带谱熵居于波状流与弹状流之间。3种流型在分析频率为0~8.3 Hz时,呈现近似线性变化的结构复杂性特征以及较强的流型区分度,可以作为流型识别的准则。     

Loading problems with tool management in flexible manufacturing systems: A few integer programming models

In automated production systems like flexible manufacturing systems (FMSs), an important issue is to find an adequate workload for each machine for each time period. Many integer linear programming (ILP) models have been proposed to solve the FMS loading problems, but not all of them take tools into account. Those that do not consider tooling are quite unrealistic, especially when setup times are important with respect to processing times. When tool loading has to be handled by the model, the load assignment may have to be changed completely.In this article we consider FMSs with a tool management of the following type: the system works in time periods whose durations are fixed or not; and tools are loaded on the machines at the beginning of each time period and stay there for the whole time period. Tool changes may occur only at the end of each time period when the system is stopped.We present some integer programming models for handling these situations with several types of objectives. Emphasis is laid on the ILP formulations. Computational complexities are discussed.     

曲轴的疲劳断裂分析

系统阐述利用有限元法对机械结构零部件进行疲劳断裂分析的相关理论和方法。在此基础上对16V240机车柴油机曲轴的最危险曲拐进行最大和最小工况下的三维有限元分析，确定裂纹易产生的危险截面，求解危险截面处不同深度和形态的表面椭圆裂纹的应力强度因子，并拟合关于椭圆裂纹特征参数及总体坐标下的等效应力强度因子的近似表达式。为预测含裂纹曲轴的承载能力、剩余寿命、制定判废标准等提供相关的疲劳断裂参数。     

基于电液伺服系统的多绳缠绕式提升机浮动天轮主动调绳性能研究

在多绳缠绕式超深矿井提升机运行过程中,采用基于电液伺服系统的浮动天轮主动调绳装置,调节钢丝绳的张力。根据浮动天轮主动调绳装置的结构和原理建立阀控缸液压伺服系统的数学模型,设计了电液伺服系统的模糊自适应PID控制器,提出了一种基于模糊自适应PID控制的电液伺服系统实现浮动天轮主动调绳的控制方法,并建立了相应的数字仿真模型,以不同扰动频率的正弦函数输入模拟钢丝绳的振动,分析了液压缸的动态特性。仿真结果证明了采用模糊自适应PID控制方法的电液伺服系统浮动天轮主动调绳装置的有效性。     

Transverse vibration of flexible hoisting rope with time-varying length

The nonlinear vibration of a flexible hoisting rope with time-varying length is investigated. The governing equations of the flexible hoisting rope are developed based on Hamilton’s principle. Experiments performed evaluated the theoretical model and found that the experimental data agree well with the theoretical prediction, which validates the mathematical model of the flexible hoisting system. The results of the simulations and experiments show that the flexible hoisting system dissipates energy during downward movement (thus is stabilized) and gains energy during upward movement (thus is unstabilized). In addition, a passage through resonance in the hoisting system with periodic external excitation is analyzed. Due to the time-varying length of the hoisting rope the natural frequencies of the system vary slowly, and transient resonance may occur when one of the frequencies coincides with the frequency of an external excitation.     

钢丝绳弱磁探伤数值模拟及实验研究

在对绞线钢丝绳3D建模的基础上,采用有限元技术,分析了弱磁励磁状态下,钢丝绳复杂表面的磁场分布;对钢丝绳周围空气中的漏磁场矢量进行了仿真,研究了缺陷对钢丝绳表面及空间漏磁场分布的影响。仿真分析结果表明:在无缺陷状态下,钢丝绳周边空气中的漏磁场分布与其绳股形状相对应,其圆周方向的漏磁场呈周期性变化,周期为绳股节距;当缺陷存在时,漏磁场分布的周期性被破坏,且幅值大幅增加。依据理论分析结果,搭建了基于弱磁励磁的钢丝绳无损探伤实验平台,得到了不同断丝缺陷的漏磁场实测波形,实验结果验证了仿真分析结果的正确性。     

Dynamic simulation of wire rope with contact

We present a dynamic simulation of a wire rope involving both contacts with a winch drum and hydraulic systems using the finite element method. Rapid winch operation often causes disorderly winding of the wire rope, which is an important quality problem. Dynamic simulation is, therefore, required for design of the hydraulic winch system on construction machinery. The wire rope is modeled using by truss elements considering large displacement motion. The contact between the wire rope and the winch drum is modeled using by variable-length truss elements and bilinear spring elements. An improved Newton method is proposed for nonlinear dynamic analysis. Simulation results show that some lever operations result in rope looseness and intense pressure fluctuation. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Etsujiro Imanishi received his master degree in Mechanical Engineering from Ritsumeikan University, in 1981. He is working for KOBE STEEL, LTD. since 1981. He received his doctor degree in 1992. Dr. Imanishi’s research interests include dynamics of construction machinery, numerical analysis and multibody dynamics.     

Experimental investigation on the hysteresis behavior of the wire rope isolators

Vibration isolation has been widely applied to filter the external excitation energy and impact forces in building structures and equipment. Wire rope isolator (WRI), a kind of isolator for vibration and shock isolation, shows a better performance in attenuating these forces. WRIs are able to deviate these external forces through their mechanical configuration and high-energy dissipative capabilities. The application of WRI demands knowledge of its behavior and the relation between various geometrical properties and input force. The present work investigates the influence of geometrical parameters, such as wire rope diameter, number of coils, and displacement amplitude on the hysteresis behavior of WRI under quasi-static loading in both vertical and horizontal directions. The hysteresis behavior of different WRIs was evaluated using the calculated parameters from hysteresis force-displacement curves: energy loss ratio (ELR), and effective stiffness. The study indicates that the geometric properties significantly influence the effective stiffness than the energy loss ratio. It is observed that, increased displacement amplitude results in decreased ELR and hence damping capabilities. The study also confirms that the wire rope isolator possesses a good ability in damping through its stiffness and high-energy dissipation capability.     

平车用钢丝绳拉紧装置

介绍一种用于平车装载货物的钢丝绳拉紧、牵引装置。使用时先将此装置安装于运输平车上,利用绞车功能将钢丝绳拉紧,然后使用钢丝绳夹将钢丝绳卡紧。钢丝绳被卡紧后将该装置撤掉。该装置节约了运输成本,操作简便快捷,提高了工作效率。     

钢绳环式无级变速器钢绳环轴向偏移分析

针对钢绳环式无级变速器(WR-CVT)在传动比变化过程中钢绳环的轴向偏移限制了CVT速比变化范围和承载能力这一问题,以钢带环轴向偏移为参考,建立了钢绳环轴向偏移量计算模型,计算结果显示最大偏移量为0.6369mm,最大偏移角为0.23°,该最大偏移量、最大偏移角较相同参数及条件下金属带式无级变速器（MB-CVT）钢带环的相应参数分别减小15.8%和0.04°。钢绳环在金属块鞍面圆弧槽内的滚动致使其承载能力优于钢带环。     

矿井提升钢丝绳断绳分析与预防措施

分析了造成提升钢丝绳断丝的原因,提出了相应的预防措施.通过采取正确、有效的防护措施,延长了设备的使用寿命,保证了安全生产     

An experimental investigation on composite fretting mode

An apparatus for composite fretting tests on a steel ball opposite to the inclined steel flat with different inclined angles (60° and 45°) have been carried out. During the tests, the maximum imposed loads were varied from 200 N to 400 N and 800 N at a constant loading speed of 12 mm/min. Dynamic analysis in combination with microscopic examinations through optical microscopy, profilometery, and SEM have been performed. Composite fretting behaviour has been analyzed and compared with the conventional fretting.