1420冷连轧机的动态特性及颤振分析

冷连轧的颤振现象是世界各国普遍关心的课题。针对我国某钢厂1420冷连轧出现的颤振现象,从实测人手分析了它的振源和颤振频率,又用有限元分析方法验证了机座发生颤振的实验结论。作为颤振振因的深化研究,对颤振出现前的“拍振”现象进行了分析,推证了轧制过程中有一个自激频率,存在,而且当它与轧机系统的某个固有频率无限接近时会立即引起轧机工作的不稳定。最后,通过建立该系统的非线性扭振微分方程和它的摄动解,进一步证明这种不稳定现象出现是由于轧制速度提高到一定值时系统内产生了负阻尼,其结论是负阻尼是引起轧机颤振的振因。

Analysis of Dynamic Characteristics and Chatter of A 1420 Cold Tandem Rolling Mill

Chatter phenomenon on cold tandem rolling mills is a general subject that is concerned about by the world.The authors analyze the vibration source and the chatter frequency with measurements and the measurement results obtained from a 1420 cold tandem rolling mill in a factory are verified by the numerical simulations with the finite element method.As a further studying, the "beat" oscillation phenomenon appearing beforce the chatter occurs is analyzed and it is found that there is a self-excited vibration frequency f during the rilling.Farthermore,if the frequency f is infinitively close to one of the natural frequencies of the rolling mill system then an instability will occur.At last,through building the nonlinear differential dynamic equations for the forsional vibration of the system and finding their perturbation solations it is concluded that the cause of the instability is due to that there will a negative damping when the rolling speed reaches a certain high value.It is this negative damping that leads to the chatter of the system.