Experimental Investigations and ALE Finite Element Method Analysis of Chatter in Cold Strip Rolling

Chatter is the most important limitation in high speed rolling of thin strips in modern industrial cold rolling mills. To study chatter in rolling, it is necessary to set up models for the rolling process as well as the mill stand. Existing models of the rolling process are analytic and are based on many simplifying assumptions. In current work Arbitrary Lagrangian Eulerian (ALE) finite element method is utilized for the first time to model the chatter vibrations in rolling, which relaxes many of these assumptions. The model has the benefit of mass translation to computational region by using ALE technique, which tremendously reduces huge computational requirements of the common Lagrangian models. The presented model is updated for simulating the chatter mechanism by means of some online velocity sensors and signal filtering method in applying the ALE boundary conditions. Results of the finite element model were compared with the experimental measurements obtained from a full scale industrial mill. Two main chattering characteristics, i.e., the critical rolling speed and the chatter frequency, obtained from the simulation program were found to be in good agreement with that of the experimental measurements.