考虑间隙与带钢振动的轧机主传动系统非线性扭振研究

发布时间：2018-05-24 05:46

本文选题：轧机主传动系统 + 非线性振动　；参考：《燕山大学》2015年博士论文

【摘要】：轧机振动问题是困扰钢铁行业多年并给生产带来严重影响与危害的技术难题,其现象异常复杂。主传动系统扭转振动(扭振)是影响产品质量的重要因素,也是轧机振动的主要形式之一。在轧机主传动系统扭振分析中,由于设计、安装和磨损等原因造成的间隙对扭振影响是不可忽视的。另外,带钢振动在板带轧机轧制过程中不可避免,带钢对主传动系统扭振的影响也鲜有人重视。本文主要针对考虑各部位间隙的轧机主传动系统扭振,带钢振动以及带钢对主传动系统扭振的影响进行分析和研究。主要研究工作如下:采用集中质量法建立轧机主传动系统5自由度离散型扭振模型,基于实测数据确定模型参数及外力载荷形式,并对扭振系统进行固有特性分析。再根据系统中间隙存在的实际位置及电动机拖动特性,将已建立的扭振模型优化为4自由含间隙的非线性扭振动力学模型。基于含间隙扭振系统动力学模型,分别在打滑和咬钢冲击状态下考虑间隙对扭振系统的影响。采用龙格-库塔方法进行数值计算,得到间隙影响的扭振系统动态响应数值结果。比较分析不同间隙简化形式对系统动态响应及各轴段扭矩放大系数(TAF)的影响,以及不同间隙位置和尺寸对扭振系统各轴段TAF的影响。根据轧辊与带钢的运动机理,建立轧辊与带钢耦合的非线性动力学模型。将连轧过程中的带钢等效为轴向运动Euler梁,轧辊等效为定轴转动的惯性元件,基于哈密顿原理,建立惯性边界下轴向运动Euler梁的非线性振动方程,利用Kantorovich时间平均法简化运动方程和边界条件,并采用修正迭代法求解振动方程。通过数值计算获得带钢非线性振动的幅频响应曲线,并讨论惯性边界下的带钢轴向速度、带钢张力、机架间距以及轧辊转动惯量等参数对带钢振动特性的影响。针对带钢对轧机主传动系统扭振的影响,建立带钢与双机架传动系统耦合扭振模型,并进行模态分析,获得系统的固有频率和固有振型。然后对带钢横断面施加激振力进行谐响应分析,通过对比模态分析结果,进一步研究带钢与轧机主传动系统扭振之间的固有属性关系。综上所述,轧机主传动系统扭振的工程控制和优化设计依赖于对系统复杂运动特性的深入了解和研究。在对轧机主传动系统扭振进行分析时,将间隙实际位置、实际尺寸及带钢振动等因素加以考虑,建立具体的符合实际的动力学模型和数学模型,这样才能得到更合理、更准确的分析结果,为轧机系统的设计分析和主传动系统扭振的工程分析提供重要的参考价值和理论依据。
[Abstract]:The vibration problem of rolling mill is a technical problem which has troubled the iron and steel industry for many years and has brought serious influence and harm to the production. Torsional vibration (torsional vibration) of main transmission system is an important factor affecting product quality and one of the main forms of rolling mill vibration. In the analysis of torsional vibration of main drive system of rolling mill, the influence of gap caused by design, installation and wear on torsional vibration can not be ignored. In addition, the vibration of strip is inevitable in the rolling process of strip mill, and the influence of strip steel on torsional vibration of main transmission system is seldom paid attention to. In this paper, the torsional vibration of main transmission system of rolling mill, the vibration of strip steel and the influence of strip steel on torsional vibration of main transmission system are analyzed and studied. The main research work is as follows: a 5-DOF discrete torsional vibration model of main drive system of rolling mill is established by means of concentrated mass method. Based on the measured data, the parameters of the model and the form of external force load are determined, and the inherent characteristics of torsional vibration system are analyzed. According to the actual position of gap and the characteristics of motor drag, the established torsional vibration model is optimized to a nonlinear torsional vibration dynamic model with 4 free clearances. Based on the dynamic model of torsional vibration system with clearance, the effect of clearance on torsional vibration system is considered under sliding and steel bite impact respectively. By using Runge-Kutta method, the numerical results of dynamic response of torsional vibration system affected by clearance are obtained. The effects of different clearance simplified forms on the dynamic response of the system and torque magnification factor of each shaft segment are compared and analyzed, as well as the effects of different clearance positions and sizes on the TAF of each shaft segment of the torsional vibration system. According to the motion mechanism of roll and strip, a nonlinear dynamic model of roll and strip coupling is established. The strip in continuous rolling process is equivalent to an axially moving Euler beam, and the roll is equivalent to an inertial element with a fixed axis rotation. Based on the Hamiltonian principle, the nonlinear vibration equation of an axially moving Euler beam with inertial boundary is established. The equations of motion and boundary conditions are simplified by Kantorovich time averaging method, and the vibration equations are solved by modified iterative method. The amplitude-frequency response curves of nonlinear vibration of strip are obtained by numerical calculation, and the effects of axial velocity, tension, stand spacing and roll moment of inertia on the vibration characteristics of strip are discussed. In view of the influence of strip steel on torsional vibration of main drive system of rolling mill, the coupled torsional vibration model of strip and double frame transmission system is established, and modal analysis is carried out to obtain the natural frequency and mode shape of the system. Then the harmonic response analysis of the excited force applied on the cross section of the strip is carried out, and the relationship between the torsional vibration of the strip steel and the main drive system of the rolling mill is further studied by comparing the results of the modal analysis. In conclusion, the engineering control and optimal design of torsional vibration of the main drive system of rolling mill depend on the deep understanding and research on the complex motion characteristics of the system. In the analysis of torsional vibration of main drive system of rolling mill, the actual position of clearance, actual size and vibration of strip steel are considered, and concrete dynamic and mathematical models are established to get more reasonable results. More accurate analysis results provide an important reference value and theoretical basis for the design and analysis of rolling mill system and the engineering analysis of torsional vibration of main drive system.
【学位授予单位】：燕山大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG333

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