Study On Dynamic Design Of Rolling Mill

Good dynamic characteristics of mechanical structure is the premise to ensure the safe and reliable operation of equipment.The dynamic design of the structure enables the designer to estimate the dynamic characteristics of the product at the design stage,and to design or modify the parameters of the structure according to the requirements,so that the product can meet the requirements of high performance,low vibration and light weight.The vibration forms of rolling mill mainly include the torsional vibration of the main drive system and the vertical vibration of the stand system.The vibration of rolling mill not only harms the quality of the strip,but also affects the service life of the rolling mill.Therefore,it is necessary to study the dynamic design of the rolling mill.This subject takes a six-high rolling mill as the research object,and uses dynamic design theory methods to conduct dynamic design research on the rolling mill,which based on sensitivity analysis and reanalysis of modified structure to improve the dynamic characteristics of the rolling mill.(1)The components of the main drive system of the rolling mill were simplified,the branching dynamic model of the main drive system was established,the moment of inertia and torsional stiffness of each component were calculated,and the mathematical model of the main drive system was established.The natural frequency,mode of vibration and torque amplification coefficient of the main drive system were solved by vibration theory,and the influence of the ratio of adjacent natural frequencies on the torque amplification coefficient was analyzed.(2)The three-dimensional model of the rolling mill stand system was established and the necessary model simplifications were made.The finite element model of the stand system was established through the finite element software ANSYS Workbench.The natural frequencies and vibration shapes of the frame,frame and upper roller system were obtained by using the modal analysis module of the finite element software.The harmonic response analysis of the frame and stand was carried out by using the response analysis module of the finite element software.(3)The ratio of the adjacent natural frequencies of the system were determined as the target parameter for the dynamic design of the main drive system.By using the sensitivity analysis method,the sensitivity values of the natural frequency of the main drive system to the moment of inertia and torsional stiffness of each element were calculated,and the influence laws of the moment of inertia and torsional stiffness with large sensitivity values on the natural frequency of the system were analyzed and the design variables were determined.The dynamic design of the main drive system of the rolling mill was carried out to improve the dynamic characteristics of the system.(4)The natural frequency,maximum deformation,maximum stress and mass of the frame were determined as the target parameters for the dynamic design of the frame.The finite element software parameter correlation analysis module was used to calculate the sensitivity values of the target parameters to the frame structure design parameters,and the response surface analysis module was used to analyze the influence rules of the design parameters with larger sensitivity values on the target parameters and determine the design variables.The dynamic design of the frame is carried out through the objective drive optimization module,which improves the dynamic characteristics of the frame system and meets the lightweight requirements.