大型悬挂式惯性振动设备若干关键问题研究

发布时间：2018-01-06 19:43

本文关键词：大型悬挂式惯性振动设备若干关键问题研究　出处：《南京理工大学》2014年博士论文　论文类型：学位论文

【摘要】：本文以大型悬挂式惯性振动设备——高方平筛为研究对象,针对其运转过程中出现的有害振动和结构破坏,运用非线性弹性力学理论、交流电机瞬态分析理论和数值模拟技术对高方平筛柔性吊杆非线性弹性特性、系统整体动力学特性、起动和停车多场耦合瞬态过程、结构破坏原因和动态设计方法等关键问题进行了深入的研究和探索。为高方平筛这类悬挂式振动机械的动态分析、有害振动抑制和惯性激振装置设计提供理论依据。主要内容如下： 1.针对大型悬挂式振动设备关键悬吊弹性部件——柔性吊杆的非线性弹性特性进行了研究。建立了柔性吊杆轴向受力横向大变形非线性梁力学模型。考虑梁轴线可伸长、大转角和大变形导致的几何非线性,并将力平衡方程建立在梁大变形的构形基础上,得到了轴向受力横向大变形梁非线性微分控制方程组。通过数值模拟,分析了轴向力、横向力和梁两端边界条件对梁变形的影响规律；得到了柔性吊杆自由端横向和轴向变形非线性弹性特性曲线,为悬挂式振动设备的动力学建模提供理论基础。 2.提出了刚柔耦合的高方平筛系统动力学建模方法。分析了四组吊杆束变形运动与筛体刚体运动的几何约束关系,建立了惯性振动设备的非线性动力学模型,给出了系统稳态振幅和低阶固有频率的计算方法。采用有限元方法,对系统进行了模态分析和动力学响应分析,并对筛体稳态运转状态进行了测试,实验结果验证了理论分析。 3.针对高方平筛在起动阶段存在的共振现象,对采用自调式惯性激振方式的系统起动多场耦合瞬态过程进行了研究。考虑柔性吊杆束自由端横向刚度非线性、异步电动机起动瞬态过程和滚动轴承摩擦,建立了系统起动瞬态过程的刚、柔、电多场耦合数学模型。分析了原激振方式下起动瞬态共振的产生、发展和衰减过程,揭示了自调式激振方式对起动瞬态共振的抑制机理。在深入分析自调式激振装置各参数对起动瞬态共振影响基础上,提出了一种新的刚度可变自调式惯性激振方式,该激振方式不但能进一步减小起动阶段最大瞬态振幅,还能降低减振效果对相关参数的敏感度,提高减振稳健性。 4.针对高方平筛在停车阶段存在的共振现象,对采用自调式惯性激振的系统停车瞬态过程进行了数值模拟研究。考虑异步电动机制动时机械特性,分析了原激振方式下停车瞬态共振的产生机理,揭示了自调式激振方式对停车瞬态共振的抑制机理和影响因素。研究了新型激振方式下系统停车瞬态过程,新型激振方式能同时使起动和停车阶段瞬态共振获得较好的抑制效果,为惯性振动机械瞬态共振的抑制提供了一种新思路。 5.对高方平筛的动强度和动态设计方法进行了研究。采用有限元方法进行了结构动力学分析,找到了结构破坏的主要原因。分析了若干因素对危险位置应力的影响,提出了改进结构强度的各种措施,这些措施和方法在合作单位工程实践中被证明是行之有效的。分析了在高方平筛大型化发展中,更有利于保持较好动强度的结构设计途经。通过上述关键问题研究,本文最终形成了一整套适应高方平筛大型化和高可靠性的建模理论和动态设计方法。
[Abstract]:In this paper, the large hanging type inertial vibrating machine - high Fang Ping screen as the research object, aiming at the destruction of harmful vibration in the operation process and structure, using the nonlinear elastic theory of AC motor, the transient analysis theory and numerical simulation of nonlinear characteristics of high flexible suspender Fang Ping sieve, dynamic characteristics of whole system, start and stop the multi field the coupled transient process, in-depth study and exploration of key issues of structural damage reason and dynamic design method. For this kind of high Fang Ping sieve suspended vibration machine dynamic analysis, provide a theoretical basis for the design of harmful vibration suppression and inertia vibration device. The main contents are as follows:
According to the nonlinear characteristics of 1. large suspended vibration equipment key parts suspended elastic flexible suspender is studied. A flexible suspension rod axial force mechanical transverse nonlinear large deformation beam model. Considering the beam axial elongation, geometric nonlinear lead to large rotation and large deformation, and the force balance equation is set up on the basis of beam configuration large deformation, the large lateral deflection of beam nonlinear differential equations of axial force. Through numerical simulation, analyzed the influence of axial force, lateral force and deformation of the beams on the two ends of the beam boundary conditions; the free end of the flexible suspender transverse and axial curve of nonlinear elastic deformation, provide a theoretical basis for dynamics modeling of suspension vibration equipment.
2. proposed high Fang Ping sieve system dynamics modeling method of rigid flexible coupling analysis. The geometric constraints of four groups of suspender bundle deformation movement and body motion, a nonlinear dynamic model of inertial vibrating equipment, calculation method of steady-state amplitude and low natural frequency are given. Using the finite element method, response analysis the modal analysis and the dynamics of the system, and the screen body steady running state were tested. The experimental results verify the theoretical analysis.
3. for the high Fang Ping sieve resonance in the starting phase, the system self adjustable inertial exciting way of starting a multi field coupling transient process is studied. Considering the flexible suspender beam free end lateral stiffness nonlinear, transient process and rolling bearing friction starting asynchronous motor, established a system of starting transient process just. Soft power, multi field coupling mathematical model. Analyzed the transient resonance excitation mode of the original starting, development and decay process, self adjustable excitation mode to start transient resonance suppression mechanism was revealed. In depth analysis of the self adjustable exciter parameters on starting transient resonance effects based on a a new variable stiffness self adjustable inertia vibration, the vibration mode can not only further reduce the starting phase, maximum instantaneous amplitude, but also reduce the sensitivity of the damping effect on the relevant parameters, to improve the damping Robustness.
4. for the high Fang Ping sieve resonance in the stage of the parking, parking system transient self adjustable inertial exciter is studied by numerical simulation. Considering the characteristics of mechanical brake asynchronous motor, analyzes the produce mechanism of the excitation mode of parking transient resonance, revealing the self adjustable excitation and inhibition mechanism influence on the transient resonance factors. Research on parking system parking transient process of a novel vibration mode, a new excitation mode can also make the starting and stopping phase transient resonance obtain good suppression effect, provides a new method for suppressing transient inertial vibration mechanical resonance.
5. of high Fang Ping sieve dynamic strength and dynamic design method is studied. Using the finite element method for structural dynamic analysis, found the main reason of structure failure. Analysis of effect factors on the risk of stress, put forward various measures to improve the structural strength, these measures and methods in cooperation with engineering practice proved to be effective. Analysis of the high Fang Ping screen large-scale development, more conducive to maintain good dynamic strength. Through the structural design
Through the study of the key problems mentioned above, a set of modeling theories and dynamic design methods adapted to the large-scale and high reliability of high Fang Ping sieves have been formed in this paper.

【学位授予单位】：南京理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TH237.6

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