Study On Nonlinear Vibration Of Strip Under Multi-freedom Main Transmission System Model

Rolling mill vibration is an important factor affecting strip qualit y in steel industry.Scholars have done detailed research on different forms of vibration,and the research work on coupling vibration of main transmission system and strip is relatively few.In this paper,the main driving system is simplified into a multi-degree-of-freedom model under the strip vibration characteristics analysis.Based on the principle of motion between strip and roll in rolling process,the strip in rolling process is reduced to axial moving Euler beam by energy method.The main driving system is composed of a variety of inertial elements with roll as the main body.According to the centralized mass method,the main driving system is reduced to three degrees of freedom system,and then the coupling vibration model between strip and main driving system is established.After that,based on Hamiltonian principle,the nonlinear vibration differential equation of strip vibration and main driving system coupling is established,and the boundary condition of three free system is established.The simplified equation of nonlinear vibration differential equation and boundary condition can be obtained by Kantorovich time average method,and then the nonlinear vibration equation is solved iteratively by modified iterative method.The amplitude-frequency response curves of rotor moment of inertia,axial velocity of strip steel,cross-sectional area of strip steel,frame distance,strip tension and torsional stiffness between shaft sections are obtained by using maple and matlab software.Finally,the boundary condition of the main driving system as three degrees of freedom is extended and extended to n degrees of freedom,and the general law of its boundary condition is obtained and summarized.For example,when the main driving system is two degrees of freedom and four degrees of freedom,the boundary conditions can be obtained by the general law of the boundary conditions of n degrees of freedom,and then the vibration characteristics of strip steel are analyzed,and the similarities and differences of the vibration characteristics of strip steel under different degrees of freedom are compared.To sum up,the optimal design of coupling vibration of rolling mill main drive system and strip steel requires more research on the complex motion characteristics of rolling mill system.In rolling mill design,various factors are integrated to reduce the loss during rolling.The research results of this paper provide theoretical reference for mill design and production and rolling operation.