气动载荷作用下轴向移动局部浸液板动力响应分析与振动控制研究

To solve vibration problem arises in area near air knife of the continuously hot-dip galvanization line. Based on the dynamical model of axially moving plate partially immersed in fluid under pneumatic load, this project analyzes its nonlinear dynamics characteristics. By transforming influences of fluid on plate into fluid dynamic pressure and its additional damping, differential interaction equations of plate and fluid are established. Under combined influences of air knife load and fluid dynamic pressure, self-excited vibration will happen on partially immersed plate. Adopting numerical and analytical methods, characteristics of self-excited vibration are analyzed. Wearing comes from working will lead to eccentric rotation, it will give rise to support movement, and this paper studies nonlinear dynamic characteristics of partial immersed plated under axial movement and support excited vibration, such as primary resonance, internal resonance, combined resonance, movement stability, etc. This project will reveal complex nonlinear dynamic characteristics of the system and rules of influence upon vibration characteristics placed by different systematic parameters, then to establish on-line control of surface quality system. Fruits of this study can suppress the vibration of steel plate, which are of great importance in improving the quality of galvanization layer. This project also provides effective theoretical foundation for the dynamics optimum design for galvanization plate.

针对连续热镀锌生产线上，气刀附近带钢的振动问题，以气动载荷作用下轴向移动局部浸液板为动力学模型，分析其非线性动力学特性。将流体对板的作用力转换为流体动压力及附加阻尼, 建立了板与流体的耦合振动微分方程。浸液板在非线性气动载荷及流体动压力共同作用下将引起自激振动，应用解析法和数值方法分析其自激振动特性。辊子工作时由于磨损可能产生偏心转动，引起支撑运动，研究支撑激励下轴向移动局部浸液板的主共振、内共振、组合共振及稳定性等非线性动力学特性。项目预期将揭示系统复杂的非线性动力学特性以及系统各参数对其振动特性的影响规律，建立带钢表面质量在线控制系统。项目的研究成果能够抑制带钢振动，对于提高镀锌层质量具有重要的意义，可以为镀锌板的动力学优化设计提供有力的理论依据。

本项目针对连续热镀锌生产线上，气刀附近带钢的振动问题，将其转化为轴向移动局部浸液板动力学模型，分析了其全局非线性动力学特性。基于Von Kármán大挠度板理论，建立了移动板与液体耦合的振动微分方程；研究了浸液板的固有特性；分析了气动载荷作用下轴向移动浸液板的动力学特性，考察了轴向移动速度、气动载荷大小、轴向张力等参数对系统非线性振动特性的影响；分析了支撑激励下轴向移动浸液板的1:3内共振特性，讨论了支撑位移幅值、轴向张力及轴向移动速度等参数对系统振动响应的影响，并进一步研究了系统内共振存在的机理；研究了轴向移动浸液板受周期激励状态下横向振动的非线性动力学特性，考察了系统随外激励幅值、移动速度、外激励频率等参数变化时的分岔行为，借助于相图、Poincaré映射图识别系统的非线性动力学行为；考虑锌锅沉没辊组件频繁振动会干扰带钢运行速度，使带钢运行速度产生波动，研究了时变速度下轴向运动浸液板的非线性振动特性，讨论了平均速度、脉动速度频率、脉动速度幅值及轴向张力对系统动力学响应的影响，分析了不同参数变化时系统可能出现的混沌和分岔行为。基于以上对轴向移动浸液板动力学特性的详细分析，发现轴向移动速度、轴向张力及气刀喷嘴压力对板振动特性的影响较为显著，可将这些参数作为带钢表面质量在线控制的主要参数，通过控制这些参数的取值范围，可有效稳定带钢振动，提高镀锌层质量。