Modeling Of Rolling Force Under Mixed Lubrication Regime And Research On Coupling Vibration Characteristics Of Rolling Mill

In the daily life,the strip material plays an indispensable role,various industries have different degrees of demand for the products after the strip material cutting and stamping.In order to ensure the stability of rolling production process and improve the efficiency of rolling production,in this paper,the dynamic rolling force model under mixed lubrication friction regime was established,and the horizontal-vertical coupling vibration characteristics of mill roll system containing dynamic rolling force were studied in depth.Detailed research contents are as follows:Firstly,the key issues involved in rolling force modeling process were discussed and several classical rolling force models were introduced,and the common rolling lubrication state,the effect of rolling technology lubrication and other lubrication theories were deeply analyzed.It was also discussed that the basic forms and characteristics of vibration of various common rolling mills,and the multi-scale method and other nonlinear vibration main analytical methods were analyzed.Secondly,the Karman unit pressure differential equation was linearized,and according to the surface real contact area ratio and the oil film thickness at any position in the working area,the expression of the total friction stress under the mixed lubrication regime was given.Taking into account the boundary conditions at the entry and exit sections,the unit normal pressure expressions of the front and backward slip area were obtained,and the dynamic rolling force model of cold rolling strip was established by numerical integration.The verification of actual industrial production data indicated that the rolling force model had high prediction accuracy,which could provide guidance for the calibration of mill equipment.Furthermore,based on the dynamic rolling force model,the effects of friction coefficient,reduction ratio,shear strength and other parameters on the distribution of unit normal pressure and the rolling force were studied.According to the concentrated mass method,and suppose there was a certain angle between the rolling force and the vertical direction,so the resultant force in the horizontal direction was equal to the difference between the product of the friction coefficient and the vertical component of rolling force and the horizontal component of rolling force.After simplification and arrangement,the horizontal-vertical coupling vibration dynamics equations of mill roll system were presented.Finally,according to the multi-scale method,the main resonance and internal resonance amplitude-frequency responses of the coupling vibration dynamics equations were obtained respectively,and the main resonance and internal resonance amplitude-frequency characteristic curve were presented.The effect and rule of the external disturbance force and various nonlinear parameters of mill structure on the coupling vibration characteristics of the mill was analyzed in depth,which would provide more theoretical reference for the solution of the complex coupling vibration problem of the mill.