296 / 2021-04-20 23:31:29

Research on the Nonlinear Characteristic of Main Drive System under Multifrequency Excitations in Hot Tandem Rolling Mill

rolling mill, main drive system, complex wavelet transform, , nonlinear dynamic characteristics

The main drive system of rolling mill is commonly forced by rolling torque and electromagnetic torque. The equivalent, two-degree and roll bite nonlinear dynamic model of transmission system is firstly established. The functions of amplitude, phase angle and instantaneous frequency are obtained by using the methods of averaging. Combining the roll-bite impact signal collected from the field test, Morlet complex wavelet transform theory is introduced and applied to identify nonlinear stiffness and damping parameters in the established dynamic model. Then the recognized nonlinear parameters will be applied to the rebuilt equivalent two-degree nonlinear dynamic model of transmission system with multifrequency disturbances. By using Melnikov method and combining with bifurcation portrait, phase portraits and Poincare maps, the dynamic characteristics of the rebuilt model under combination resonance are analyzed. The analysis results indicate that with the perturbation of linear and cubic damping, quadratic and cubic stiffness and amplitude of external excitation, the reestablished model reflects obvious and rich dynamic characteristics; the suitable nonlinear parameters and the amplitude of external excitation can promote the stability of the rebuilt model of transmission system of mill.