Research On Nonlinear Torsional And Vertical Vibration Model And Characteristic Of Strip Mill

As one of the key equipment in iron and steel industry, rolling mill plays a veryimportant role in the process of iron and steel producing. In the process of rolling,vibration is a serious technical problem which beset the iron and steel industry to improveproduct quality and restricts the rolling product quality promotion and the productionefficiency improved. In order to obtain the effectively control strategies of the rolling millvibration to ensure the operation stability of rolling mill systems, improve the quality ofrolled products, rolling mill vibration problem has become the focus of the researchers.Based on the generalized dissipation Lagrange principle, respectively established thetwo degree of freedom and the multi degree of freedom torsion vibration mechanics modelunder the parameters excitation of rolling mill drive system, considering the deformationof rolled piece showed the hysteretic nonlinear characteristics in the process of loadingwith cyclical change, the establishment of mill roll system lag nonlinear vibration model,considering under the action of hydraulic cylinder, the system show more piecewiseconstraints nonlinear factors, establish the multiple piecewise nonlinear strip mill verticalvibration model. These five models provide basis of theory for studying on the rolling millnonlinear vibration characteristics in further.Use the method of multiple scales, the incremental harmonic balance method, thenonlinear solution for each model the approximate analytical solution, analysis mill in andexcitation, answer axial clearance, work piece hysteretic deformation and hydrauliccylinder under the restriction of the many section and so on the different nonlinear factorsunder the influence of the vibration characteristic, research with different parameters onthe mill the factors influencing the stability of the law. By using Lyapunov stability theoryand singularity theory analysis mill vibration system stability, and get mill nonlinearvibration system instability critical condition.Based on the research of HHT non-stationary signal time and frequency analysis, thepaper proposes boundary characteristic scale continuation method, through the use ofsignal internal and edge change trend the most similar wavelet to tip data continuation, restrain HHT time-frequency analysis of end effect. As the test data of1780hot rollingmill drive system torsion vibration and frame system vertical vibration an example, theuse of HHT method to actual mill drive system torsion vibration and mill roll systemvertical vibration signal feature extraction, verify the influence existing in the mill andexcitation, answer axial clearance, the work piece deformation hysteretic and hydrauliccylinder under the action of show more section and so on the different nonlinear factors onthe rolling mill drive system torsion vibration and mill roll system vertical vibrationcharacteristic.Through the study found that system influenced by different nonlinear factors willproduce the corresponding nonlinear vibration behavior, to the stability of the rolling stripmill, threaten, when nonlinear degree to certain degree system will appear rollinginstability phenomenon. Through the stability analysis found that rolling parameters in arange of rolling stability when change, the use of vibration system instability criticalcondition can give stable rolling parameters area, to rolling production process parametersset provide guidance.