WSEAS Transactions on Applied and Theoretical Mechanics
Print ISSN: 1991-8747, E-ISSN: 2224-3429
Volume 11, 2016
Determination of Self-Excited Vibration Criterion for Strip Rolling Mills
Authors: , , ,
Abstract: Self-excited vibration has been occasionally observed with a nature frequency of the mill stand during the strip rolling process. The root cause of this phenomenon has not been clearly explained yet. In general, it is related with rolling reduction ratio, rolling speed, frictional condition and material mechanics etc. According to the evolution of vibration amplitude, self-excited vibration can be classified into stable type with decreasing amplitude and unstable type with increasing amplitude by a critical condition where the vibration amplitude keeps unchanged. This critical condition is a criterion which can distinguish the type of self-excited vibration and help to escape the unstable self-excited vibration as well as prolong the rolling mill’s lifetime. This paper is aimed to determine the self-excited vibration criterion of a typical rolling mill. Based on different solutions to the mill’s differential vibration equations under different operational parameters, critical conditions mean that characteristic roots’ real parts are either zero or negative. They constitute the criterion curve in corresponding operational parameter field. The differential vibration equations of rolling mill are simplified as a set of second-order equations by assuming that the deformation region of the strip is equivalent to springs and damps. Then the equivalent damping and stiffness matrices can be calculated using 2D rigid-plastic FEM through applying perturbations of roll displacement and velocity. Compared with measured data, the predicted self-excited vibration criterion is proved to be reasonable. It’s believed that this research will be meaningful to optimize the rolling operational parameters and avoid the occurrence of unstable self-excited vibration.
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Pages: 97-106
WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #12