混联弹簧减振系统下自同步直线振动筛的动力学特性

Dynamic characteristics of a self-synchronous linear vibrating screen with hybrid-spring isolators

混联弹簧减振系统(由并联座式弹簧组和悬挂弹簧组合构成)下自同步直线振动筛稳态振幅增大、竖直方向运动固有频率提高,停机过共振区时位移响应较仅座式弹簧减振情况明显减小,有利于振动筛整体可靠性的提高。为了解混联弹簧减振系统下自同步直线振动筛的动力学特性,在考虑设计、制造等引起的筛体质心偏离激振力作用线的基础上,建立了直线筛的一般数学模型,并推导其振动微分方程;引入小阻尼近似法,利用已有的筛体参数反推模型中的阻尼矩阵;采用Newmark-β数值仿真与现场实验测试相结合,从时、频域验证了模型的可行性。基于此,进行结构灵敏度分析,讨论了混联弹簧减振系统中悬挂弹簧刚度及位置对直线振动筛竖直方向固有频率的影响,为实际中这两个参数的选择提供参考。

A prior vibration response test on a self-synchronous linear vibrating screen （LVS） with hybrid-spring isola- tors, which were composed of the parallel springs and the suspended springs, was conducted in this study. The results show that the stable vibration amplitude and the natural frequency of the LVS with hybrid-spring isolators are im- proved, and after external exciting eliminated, the resonance displacement of such a LVS apparently decreases in com- parison with a LVS mounted on traditional compression spring isolators. In order to investigate the dynamic characteris- tics of the LVS with hybrid-spring isolators, with the consideration of the mass center departure from the exciting force induced by design or manufacture error, a general mathematical model was established and followed by deriving the vi- bration differential equation. Moreover, based on the available screen structure parameters, the practical small-damp- ing-approximate method was adopted to have the damping matrix evaluated. Then, the displacement response data sim- ulated by the Newmark-β method and tested in practice were analyzed to demonstrate the accuracy of the developed mathematical model. Finally, the sensitivity of the vertical natural frequency to the position and the stiffness of suspen-ded spring were analyzed and discussed,whieh provides a foundation fi^r tile determination of two paramelers.