Dynamic Modeling Research Of Rolling Mill System Based On The Roll System’s Rigid And Flexible Coupling Property

Metal plate plays a very important role in the national economy and national defense modernization. Rolling process is a typical complex nonlinear dynamic process, and the dynamic characteristic is composed of mill roll system and moving plate with different physical properties of movement determined by interaction. This application makes four-high mill system as the research object, by analyzing the motion characteristics and coupling relationship between roll system and strip, revealing the strip rolling mill’s dynamic mechanism based on the rigid-flexible coupling characteristic of roll system, set up the corresponding dynamic model, and on the basis of simulation analysis, to develop the corresponding dynamic controller.The coupling mechanism between the motion of the roll system and dynamic characteristics of the moving strip during the rolling process was also studied. In the current paper, the rolling mill system is equivalent to a flexible multi-body mechanical system composed of rigid and deformable bodies, which are connected to each other by different constraints. The displacement field of rigid and deformable bodies in the system is built by dynamic analysis with vertical movement, horizontal movement, work roll’s rotation, rigid movement and elastic movement of the moving strip taken into account. Then, the law governing the strong nonlinear inertial and stiffness coupling effect caused by the co-effect of rigid motion and elastic deformation of the system structural elements is determined. Furthermore, a flexible multi-body system for a coupling vibration model of the strip rolling mill is established. Consequently, the dynamic response of roll system and the working stability of rolling mill can be analyzed, and a theoretical foundation for the dynamic control of the strip thickness is provided.Moreover, the influence of the dynamic properties of rolling mill system’s rigid vibration on the work roll and backup roll’s flexural deformation movement was investigated. In addition, the displacement field of rigid and deformable bodies in the system is built by dynamic analysis with vertical movement, horizontal movement, work roll’s rotation and flexural deformation movement of the rolls taken into account. Furthermore, a rigid flexible coupling dynamic model of the strip rolling mill is established. In the current work, the coupled motion modal analysis was made for the roll system. More explicitly, the analytical solutions for the flexural deformation movement’s vibration frequency and mode shape functions of rolls were discussed. Consequently, the difference between the natural mode shape function of the roll derived by the traditional structural dynamics and the mode shape function deduced with the influence of rolling mill’s rigid vibration has been analyzed in different moments.More explicitly, the coupling law between the roll system’s flexural deformation movement and the stock’s transverse movement in the rolling deformation area was investigated. In addition, the displacement field of roll system and lateral flow of metal is described by kinematic analysis in the dynamic system. Furthermore, a multi-parameter coupling dynamic model of the roll system and stock is established. In the current work, the coupled motion modal analysis was made for the roll system. More explicitly, the analytical solutions for the flexural deformation movement’s natural frequency and mode shape functions of rolls were discussed. In addition, the dynamic characteristic of the lateral flow of metal in the rolling deformation area has been analyzed at the same time.The rolling mill system’s dynamic model system based on the roll system’s rigid-flexible coupling property is consisted with three models: the coupling vibration model of the strip rolling mill, the rigid flexible coupling dynamic model of the strip rolling mill and the coupling dynamic model of rolling deformation area. Based on the characteristics of the model itself, the central difference method for numarical simulation was used. The model can be used to simulate the rolling process, which can reflect the shape and thickness complex dynamic information, provide a theoretical basis for virtual rolling, providing a platform for advanced control theory and application.The application from the physical, mechanical properties of point of view, combined with the strip- roll system coupled inhomogeneous deformation, truly reflects the dynamic characteristics of the rolling mill and metal plate, reveals the rolling stability, the strip surface ripples, bite mechanism of steel cast steel dynamic process. Coupling dynamic model to promote the development of the mill dynamic modeling of the system, has important theoretical and practical value to improve the precision of rolling process control.