Research On Dynamic Model And Vertical Vibration Characteristics Of High-speed Cold Rolling Mill Under Multiple Nonlinear Constraints

Four-high-speed cold rolling mill was taken as the research object in this paper.Considering the influences of nonlinear dynamic rolling force,piecewise nonlinear elastic constraints and piecewise nonlinear friction constraints,dynamic model of high-speed cold rolling mill under multiple nonlinear constraints was established and the response was solved.The amplitude frequency response characteristics and stability are anlyzed by numerical simulation.The vadility of dynamic model was verified by comparing engineering test data and simulation results.The main contents of the paper are as following:(1)The process of high-speed cold rolling mill was analyzed.Considering elastic deformation,plastic deformation and roll falttening radius,the model of nonlinear dynamic rolling force was established based on the model of Bland-Ford-Hill rolling force.The relationship between nonlinear dynamic rolling force and vibration displacement was achieved by decoupling the model and the influences of main parameters on nonlinear dynamic rolling force were studied.(2)The structure of high-speed cold rolling mill was analyzed.Nonlinearity of elastic stiffness of hydraolic oil and the nonlinearity of friction coefficient between piston rod and cylinder wall of the bending cylinder and the pressure cylinder were studied.Then the mechanical model of piecewise nonlinear elastic contraints and piecewise nonlinear friction constrains of high-speed cold rolling were established and piecewise characteristics were studied.(3)Based on the coupling relationship between nonlinear dynamic rolling force,piecewise nonlinear elastic constraints and piecewise nonlinear friction constraints,a nonlinear dynamic model of high-speed cold rolling mill was established.The inherent frequency was solved and the response was also solved by average method.Amplitude-frequency response characteristics of the main resonance,superharmonic resonance and harmonic resonance were analyzed.By simplifying the piecewise expression of dynamic model,singular point stability was analyzed and the influences of piecewise characteristics were studied by simulating phase trajectory.(4)Taking working roll,supporting roll and rack as measuring object,vertical vibration engineering verification was carried out on 2800 four-high-speed cold rolling mill.By analyzing the measuerd signal during the process of plate rolling,vibration time domain map and spectrum map were achivevd.Comparing the experimental and theoretical results,rationality of the established dynamic model were verified and correctness of simulation were verified.