液压缸非线性刚度的轧机辊系振动分析

Vibration analysis of roll system with nonlinear stiffness of hydraulic cylinde

为了解四辊轧机在轧制过程中液压缸的非线性刚度约束作用,建立了非线性刚度作用下的轧机辊系两自由度垂直振动动力学模型。依据达朗贝尔原理得到含有液压缸非线性刚度的轧机辊系垂直振动方程,运用平均法求得振动系统的幅频响应。以轧机的实际参数为例,分析液压缸非线性刚度、外激励对轧机系统幅频响应的影响,并研究在不同非线性刚度下的轧机振动行为。结果表明,液压缸非线性刚度越大,轧机系统越不稳定;液压缸非线性刚度较弱时,轧机振动行为会逐渐收敛于稳定,液压缸非线性刚度较强时,轧机振动行为会处于不稳定状态,并且出现发散现象,这为抑制轧机振动提供了理论参考。

A vertical vibration dynamic model with two degrees of freedom was established considering the nonlinear stiffness constraint action from hydraulic cylinder in the four-high rolling mill process. On the basis of D＇Alembert＇s principle,the study established the nonlinear vertical vibration equation of roll system contained nonlinear stiffness of hydraulic cylinder,and obtained the amplitude-frequency response of the vibration system by using the average method.According to the actual parameters of rolling mill,the influences of the nonlinear stiffness of the hydraulic cylinder and the external force on the amplitude-frequency response of the rolling mill were analyzed,the behavior of mill vibration under different nonlinear stiffness was investigated. The study indicated that the larger the nonlinear stiffness of the hydraulic cylinder,the more unstable the rolling mill system. The mill vibration behavior would gradually converge to stability when the nonlinear stiffness was weaker,the mill vibration would be in a state of instability and divergent when the nonlinear stiffness was stronger,which provided a theoretical basis to suppress the vibration of rolling mill rolls.