水电工程重型缆机架空索道系统动力学及可靠性研究

发布时间：2018-01-03 02:45

本文关键词：水电工程重型缆机架空索道系统动力学及可靠性研究　出处：《武汉大学》2013年博士论文　论文类型：学位论文

【摘要】：缆索起重机(以下简称缆机)是以悬挂于两支点之间的钢索作为承载结构,利用载重小车在其上往返移动进行物料吊运,兼有垂直运输(通过起升机构的起重绳实现)和水平运输功能的特种起重运输机械。缆机主要由塔架、架空承载部分、工作驱动机构、机电控制设备及安全保护装置等组成,其中架空部分主要由承载索、起重绳、牵引绳、承马及载重小车等部件组成。缆机在水利电力建设工程、桥梁建筑、码头施工、森林工业、采矿工业、堆料场装卸以及港口装卸等方面都有广泛的用途。我国在三峡大坝施工中,首次引进德国克虏伯所设计制造的缆机,并开始对国外先进缆机设计与制造技术进行引进、消化和吸收。目前我国在缆机设计、制造和使用过程中,塔架、驱动及控制系统等方面的设计和制造技术都较为成熟,使用过程也很少出现故障。但是,在对缆机中关键部件——架空系统的研究方面与国外类似产品相比仍有差距,反映在对于架空部件的优化设计、产品精细化程度不够,可靠性不高,缺乏基础性研究的支持。通过查阅文献获知,大量缆机方面的文献仅仅涉及缆机的维护、保养、运行等方面的内容。在研究中有两个明显的不足：其一是对于重型缆机索道系统的动力学特性研究不够；其二是没有运用现代设计分析方法与手段对缆机架空索道系统设计中的关键问题进行研究。由于缆机架空部分的承载索、起重绳、牵引绳及承马等部件之间存在强耦合关系,保证缆机架空部分的平稳运行成为缆机设计的关键。随着我国对缆机速度及载荷量要求的不断提高,迫切需要应用动力学和现代设计分析方法与手段,对缆机架空部分部件的运动机理进行深入的研究,以提高缆机运行的平稳性和使用可靠性。论文以现代设计理论为指导,对重型缆机中的架空系统的动力学特性以及设计中的关键问题进行了系统的研究,主要研究内容和研究成果归纳如下： 1.系统地研究了重型缆机承载索的动力学建模方法。针对缆机架空部分中起升系统与承载索之间存在的强耦合作用及缆机的结构特点,把缆机架空系统合理的抽象成悬挂于两等高固定端的均质弹性连续体和具有一定质量—刚度—阻尼的移动振子的物理模型。然后应用汉密尔顿(Hamilton)原理列写了该系统的运动方程,通过力和位移协调推导出了一组控制索—振子运动的偏微分方程组,在方程中考虑了科氏(Coriolis)惯性力以及缆索的非线性弹性恢复力。由于该微分方程组不存在封闭的解析解,因而运用伽辽金法(Galerkin)方法,把偏微分方程组转化成了常微分方程组以便利于数值积分求解。 2.针对控制索-振子运动的微分方程,对数值积分和动力学仿真的方法分别进行了研究。首先研究了形函数的阶数对收敛性的影响,根据重型缆机架空部分的结构形式,并考虑跨度、垂度以及载重量等因素,选择正弦函数作为形函数并编制了MATLAB程序。应用该程序,在缆机的匀速、紧急加(减)速、加载以及减载等典型工况下,对悬索的动力学特性进行了研究。为了对动力学分析结果进行验证,在动力学仿真软件ADAMS平台上建立了缆机承载索的动力学模型并进行了仿真,仿真结果与数值积分的求解结果基本一致。研究结果表明：小车的运动速度、吊重等对悬索的动力学特性有比较明显的影响,而其中对缆机运行平稳性影响最大的是载重小车的运行速度。对于目前使用最多的30t级缆机及其相应的架空结构,小车的最大匀速不宜超过7.5m/s,否则会导致缆索的急剧跳动,对缆机的平稳运行十分不利。结论解释了为何缆机载重小车的工作速度存在速度限制闽值。 3.运用三维建模软件和机械系统动力学分析软件,对架空系统中的重要部件——承马的结构进行了优化设计研究。论文结合承马的结构特征和设计流程,具体研究了承马的三维设计方法,并用实例进行了验证；在ADAMS平台上对承马进行了动力学仿真,通过参数优化设计,确定了保证承马托轮臂得到合理张开角度时托轮臂铰点的最优位置,在此基础上通过对承马关闭弹簧的刚度和阻尼参数的优化,可整体提高承马启闭过程的平稳性和可靠性,并提高承马启闭响应的灵敏度。 4.通过对缆机不同工况和载荷下的运行状况分析,求解状态方程确定了缆机工作时各个承马中从空中脱落风险最大的承马。以该承马的载荷和受力特性为基础,选择空载、轻载以及满载等典型工况对缆机运行过程中承马的受力状况进行有限元结构分析,确定了承马结构中最为薄弱的部分。研究方法和结果可直接应用于承马的设计工作,对承马结构轻型化、提高承马工作的可靠性具有一定参考价值。 5.对于缆机承载索的疲劳问题进行了理论研究。通过单根钢丝及整条缆索的受力分析,证明缆机承载索的疲劳与悬索桥等其他悬索结构中索的疲劳有所不同,悬索桥等其他悬索结构中索的疲劳属于轴向疲劳问题,而缆机承载索的疲劳属于弯曲疲劳问题,并从理论上论证了缆机承载索的疲劳发生在承载索的表面而非靠近索中性面的原因。通过对承载索进行有限元分析,计算出载重小车运行过程中承载索交变应力的幅值,并结合经典的应力-寿命S—N曲线,对缆机承载索的疲劳寿命的主要影响因素进行了研究,证明了承载索的疲劳寿命与缆机载重小车的循环次数、吊运重量及承载索直径等参数的关联度。通过工程实例的验算,计算出某30t级缆机在吊运300kN载荷时承载索的寿命仅仅略高于30万个工作循环,从理论上论证了承载索的国外供货方不愿对承载索的寿命做出高于30万个工作循环承诺的原因,对目前承载索安全系数的选择是一个很好的补充,并可提高缆机的使用安全性。论文对工程对象进行分析与综合,原始参数来源于工程案例,研究成果均有相应的工程实例验证,对缆机设计具有指导意义。
[Abstract]:Cable crane (hereinafter referred to as the winch) is suspended from the two pivot between the cable as the bearing structure, the trolley on the move for material lifting, both vertical transportation (by hoisting rope ascending mechanism) and transport function of special hoisting and conveying machinery. The cable machine is mainly composed of the tower overhead, bearing parts, work driving mechanism composed of electrical control equipment and safety protection device, which is mainly composed of overhead cable, lifting rope, rope, the horse and trolley and other components. The cable machine in water conservancy and electric power construction engineering, bridge construction, pier construction, forest industry, mining industry. Yard handling and port loading and unloading and other aspects of a wide range of uses.
Our country in the Three Gorges dam construction, first introduced the German Krupp designed cable machine manufacturing, and began to design and manufacture of foreign advanced technology of cable machine introduction, digestion and absorption. At present in the design of cable crane, tower manufacturing and using process, design and manufacturing technology, drive and control system etc. are more mature, the use of the process but also rarely fails. However, in the research on the key components of the overhead system of the cable machine in hand compared with foreign similar products is still reflected in the optimization design for aerial parts, product refinement degree is not enough, the reliability is not high, the lack of basic research support.
Through the literature that maintain a large number of literature on cable machine involves only cable machine maintenance, operation and other aspects. There are two obvious shortcomings in the study: one is for the study of dynamic characteristics of cable system of heavy cable machine is not enough; the other is not the use of modern design methods and means of analysis the key problems of the design of cable crane ropeway system. Because the bearing part of the overhead cable of cable crane, hoisting rope, there is a strong coupling relationship between traction rope and horse bearing parts, ensure the smooth operation of the cable machine becomes the key part of overhead cable machine design. With China's increasing demand on cable machine speed and the load, the urgent need to analyze the methods and means of application of dynamics and modern design, the movement mechanism of overhead cable machine parts in-depth study, in order to improve the stability and the use of cable machine running reliability. .
Under the guidance of modern design theory, the dynamic characteristics and key problems in design of heavy duty cable cranes are systematically studied. The main research contents and research results are summarized as follows:
1. we studied the dynamic modeling method of the load bearing cable of cable machine. For heavy lift system and bearing structure characteristics of strong coupling between the cable and cable machine overhead cable machine part, the homogeneous elastic continuum of overhead cable machine system is abstracted into reasonable hanging on the two high and has a fixed end the quality and stiffness of mobile vibrator damping physical model. Then the application of Hamilton principle (Hamilton) introduced the equation of motion of the system, through the force and displacement coordination derived partial differential equations of a set of control cable vibration, the equation considering the Coriolis inertia (Coriolis) the cable force and the nonlinear elastic restoring force. Because of the differential equations are not closed analytical solution, so the use of Galerkin method (Galerkin) method, the partial differential equations into ordinary differential equations for numerical integral Solve.
The differential equation for the vibration control of cable - 2., method of numerical integration and dynamic simulation are studied. First the influence of order shape function on convergence, according to the structure of heavy overhead cable machine part, and considering the factors of span, sag and load, select the sine function as the shape function and MATLAB program. The program is used in the cable machine speed, emergency plus (minus) speed, loading and unloading etc. under typical conditions, dynamic characteristics of the suspension are studied. In order to verify the results of dynamic analysis, the dynamic simulation software is developed on ADAMS cable machine bearing the dynamic model of cable and simulation, simulation results and numerical results are consistent. The results show that: the movement speed of the car, there is obvious influence of crane dynamic characteristics of suspension. , which effect on the running stability of the cable machine is the largest speed trolley. For the overhead structure currently used 30t cable machine up and the corresponding maximum speed, not the car more than 7.5m/s, otherwise it will lead to the rapid beating of the cable, smooth operation of the cable machine explains why is very unfavorable. Winch trolley work speed speed limit threshold.
3. using 3D modeling software and dynamic analysis software of mechanical system, the structure of the important components of overhead system -- the carrier is optimized. According to the structure characteristics and design process for the horse, specific research 3D design method of the horse, and verified on ADAMS platform is made; dynamic simulation of the carrier, through the parameter optimization design, ensured the optimal location of roller arm joint bearing wheel arm reasonable opening angle mahto when, on the basis of the optimization of the horse off the spring stiffness and damping parameters, thereby improving the stability and reliability of the process of opening and closing the horse. Ma Kai sensitivity and improve the bearing close response.
4. by analyzing the operation conditions of the cable machine in different conditions and under load, to solve the state equations to determine the work of each bearing cable machine horse from the air off the biggest risk for the horse. The horse to load bearing and force characteristics as the basis, select the load, light load and full load and other typical conditions on stress condition during the operation of the cable machine horse of finite element analysis, the weak part of the horse bearing structure. The research methods and results can be directly applied to the design work of the horse, the horse bearing light structure, which has a certain reference value to improve the reliability of the horse work.
5. for cable machine bearing fatigue problem of cable are studied. The stress of single wire and the whole cable of cable machine bearing fatigue proof cable fatigue and suspension bridge and other cable structures are different, the axial fatigue problem of cable fatigue belongs to the suspension bridge and other suspension structure, and cable machine bearing cable fatigue belongs to bending fatigue problems, and demonstrates the winch cable bearing fatigue occurred on the surface of bearing cable and non cable near the neutral plane reasons theoretically. Through the finite element analysis of bearing cable, calculate the trolley running process of bearing cable alternating stress amplitude, combined with the classic the stress - life of S - N curve, the main factors of the cable machine bearing fatigue life of cable are studied, proved that the cycles of fatigue life and carrying trolley cable machine cable, lifting weight bearing and straight cable Correlation of size parameters. Through the calculation of an engineering example, calculate a 30t cable crane in lifting 300kN load carrying rope life is only slightly higher than 300 thousand cycles, theoretically bearing cable overseas supplier to make higher than 300 thousand working cycle commitment to carrying cable life. Is a good complement to the current carrying cable safety factor selection, and can improve the safety of the cable machine.
In this paper, engineering objects are analyzed and synthesized. The original parameters are derived from engineering cases. The research results are verified by corresponding engineering examples, which is of guiding significance for design of cable cranes.

【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TH213

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