Study On Dynamic Behavior Of Rolling Mill Main Drive System Under Rolling Force Influenced By Torsional Vibration

The rolling production is becoming more and more fleetly and higher accurate, while modern industy requires rolling plate with high standard of quality and the rolling mill equipments become more and more complicated and larger. The problem caused by torsional vibration of rolling mill main drive system is becoming more and more obvious. There were some malfunctions resulted in damage of main drive system components, quality reducing of the plate which led poor efficiency of rolling production. It is a complicated electromechanical coupling system with strong nonlinear. It is important for revealing mechanism of torsional vibration in main drive system of rolling mill and controlling the vibration to analysis its dynamic characteristics.Firstly, in this paper, the rolling torque model is established according to the rolling theory by analyzing the dynamic change in rolling process. Considering the influence of dynamic rolling torque and effect of electromechanical coupling, a strong nonlinear torsional vibration model of rolling mill main drive system is established based on lumped mass method and generalized Lagrange equation.Secondly, by using the modified multiple scales method, the nonlinear torsional vibration model is solved, and the main resonance response equations of the system are obtained under the excition in motor side and load side. Then the influence of system parameters on the primary resonance is studied by using matlab. Moreover, the ultraharmonic resonance and subharmonic resonance response equation are obtained and the characteristics of the ultraharmonic resonance and subharmonic resonance are studied by using matlab.Finally, the main drive torsional vibration system of the four dimensional rolling mill is equivalents to a low dimensional bifurcation equation based on Lyapunov-Schmidt method. Then the transition set of system and the topological structure of bifurcation curves are obtained according to the singularity theory, thus the static bifurcation characteristics of the system are studied. The bifurcation diagram, the maximum Lyapunov exponent diagram, the phase trajectory diagram and the Poincare section diagram of the system are obtained while external excitation amplitude, electromagnetic stiffness and torsional stiffness of the system are changed by using the numerical method. So the dynamic behavior characteristics of the system with parameter variation are analyzed and studied.