Research On Nonlinear Torsional Vibration Of Asynchronous Cold Rolling Mill

Asynchronous rolling is an important technological means to realize ultra-thin strip rolling.This article takes asynchronous cold-rolled nonlinear torsional vibration system as the research object,and the nonlinear torsional vibration model considering the Influence factor such as transmission error,clearance and speed fluctuation is established.Through the study of the system's combined resonance,bifurcation,maximum Lyapunov exponent,attractor rheological characteristics,etc.,the dynamic evolution mechanism of the system affected by the above factors is revealed.Which provides a theoretical reference for improving the quality of asynchronous rolled strip products and suppressing and controlling nonlinear torsional vibration.The main research contents are as follows:1.Based on the Lagrange principle and a reasonable simplification of the asynchronous cold rolling system,a nonlinear torsional vibration model considering transmission errors and a nonlinear torsional vibration model considering clearance and speed fluctuations were established respectively.The bifurcation,maximum Lyapunov exponent of double parameters and attractor rheological characteristics of asynchronous cold rolling mill considering the gap and speed fluctuation are studied.The results shown that reducing the first order damping and increasing the cubic term damping can reduce the combined resonance amplitude,and reducing the cubic term stiffness and torque excitation amplitude can reduce the combined resonance tuning frequency.The influence of external excitation on the stability of the system motion is greater than that of the system parameters.Among the system parameters,damping has a greater influence than other system parameters.2.The bifurcation,double-parameter maximum Lyapunov index and the rheological characteristics of attractor of the nonlinear torsional vibration of asynchronous cold rolling mills considering the fluctuation of clearance and rotation speed are studied.The results shown that the external excitation torque and the first order stiffness are the main factors affecting the stability of the system.Increasing the external excitation torque is conducive to improving the stability of the movement in the serving system.3.Through the comparative study of nonlinear torsional vibration of asynchronous cold rolling mills considering transmission errors and clearance and speed fluctuations shows that the external excitation torque is the main factor affecting the system's motion stability under two different working conditions.The difference is that among the system parameters,damping is the main factor affecting the stability of the torsional vibration system considering transmission errors,while stiffness is the main factor affecting the stability of the torsional vibration system considering clearance and speed fluctuations.4.Considering the working characteristics of asynchronous rolling,the coupling torsional vibration of the two work rolls under the coupled action of the rolled parts is studied.It is shown that when the two work rolls are vibrated in a pure bonding periodic torsional vibration,it is beneficial to improve the rolling quality of the rolled piece and the stability of the system work.