基于弹塑性有限元的板形控制机理研究现状与展望

Present status and future prospects of strip flatness control based on elastic-plastic finite element

带钢冷连轧过程中的板形控制问题因具有多变量、多控制回路、非线性和强耦合等特征,是工业控制领域最为复杂的控制过程之一。精准的板形预测模型是提高板形控制水平的重要保证。当前,弹塑性有限元法能够耦合分析轧制过程中带钢的弹塑性变形、轧后的残余应力以及轧辊的弹性挠曲、弹性压扁,因此在带钢轧制领域有很广泛的应用。介绍了现代板形控制系统的工作原理,以及当前弹塑性有限元法关于板形控制问题分析的研究进展。同时,采用显式动态有限元建立了六辊UCM轧机的三维数值仿真模型,研究了不同板形调节机构对带钢板形的调控特性及其最优调节量,并采用实际轧制试验对模型进行了验证。结合带钢保持良好板形的几何条件,利用所建立的UCM轧机模型,分析了中间辊轴向横移、工作辊与中间辊弯辊对带钢横截面形状、凸度、边降及平直度的影响。最后,对有限元法应用于分析板形控制问题的方向进行了展望。

The strip flatness control problem in continuous cold rolling process,is one of the most complex control processes in industrial control field due to its multivariable,multi-control loop,nonlinear and strong coupling characteristics.Therefore,the accurate flatness prediction model is an important guarantee to improve the level of flatness control.At present,elastic-plastic finite element method(FEM)can be used to analyze elastic-plastic deformation,residual stress of rolled strip,elastic deflection and elastic flattening of rolls,so it is widely used in strip rolling field.In this paper,the working principle of modern flatness control system and the research progress of elastic-plastic finite element method on the analysis of flatness control problem were introduced.A three-dimensional numerical simulation model of the six-high UCM mill was established by explicit dynamic finite element method.The control characteristics and optimal adjustment quantity of different flatness actuators were studied,and the model was verified by actual rolling experiment.According to the geometric condition of maintaining good strip flatness and the mill model,the influence of the intermediate roll shifting(IRS),work roll bending(WRB)and intermediate roll bending(IRB)on the strip cross-sectional profile,crown,edge drop and flatness was investigated.Finally,the development direction of the application of the FEM to analyze the shape control problem was prospected.