精确接触边界条件下热轧带钢轧制力的仿真研究

在流面条元法基础上，将带钢与轧辊的接触面视为三维曲面，结合塑性力学中斜面上应力的求解法，给出了接触表面上的精确应力边界条件，建立了单位轧制压力与变形区内部应力的关系，实现了对板带轧制三维应力和变形的精确分析和计算。热轧带钢轧制力的仿真研究结果表明，新算法(改进算法)的计算精度高于旧算法。     

板带轧制过程多参数耦合模拟系统的开发

考虑轧件和辊系间的接触力与变形协调关系，采用一种选代的方案，开发了一个分析三维板带轧制过程的计算机模型。它耦合了计算轧件变形的三维刚塑性有限元法，计算辊系变形的影响函数法和弹性有限元法。该系统可用来精确预报轧制压力横向分布，前后张力横向分布，金属横向流动，以及轧后板带的横向板厚分布，包括板凸度和边部减薄等，并且具有较高的计算效率。     

张力对冷轧板带变形的影响

在大型商业有限元软件平台上,开发了板带轧制三维模拟系统,讨论了改变前,后张力时,轧件的三维变形特点。模拟结果显示,增加张力限制金属横向流动,加大厚向变形,使断面厚度更加均匀,其中同时改变前后张力对变形的影响效果最大。     

轧制界面非稳态流体润滑轧制特性

针对轧制过程非稳态及润滑特性,通过流体力学分析,建立稳态、非稳态轧制变形区油膜厚度分布模型,提出油膜波动系数以研究油膜厚度的绝对波动,应用卡尔曼微分方程分析了稳态、非稳态轧制界面应力分布,并以稳态应力分布为基础提出应力波动系数以研究变形区应力的绝对波动.结果表明:稳态下压下率增加,轧制界面油膜变薄,压应力、切应力均增加;非稳态下随着入口板带厚度等扰动因素的波动加剧,油膜波动系数变大,绝对波动加剧;不同时刻非稳态压应力波峰的位置和数值都会发生变化;相比于切应力,油膜波动对压应力的影响比较大,当油膜厚度发生6.33%的绝对波动时,压应力和切应力分别产生1.17%和0.24%的绝对波动.      

热轧宽带钢厚度及轧制力横向分布的研究

 板形是板带几何尺寸的一个重要指标,忽略横向变形的二维轧制理论已不能满足板形精度要求,掌握金属三维变形规律,建立各因素与出口带钢厚度分布之间的关系,可准确地进行板形设定。基于理论基础,应用影响函数法实现辊系变形计算,三维差分法求解轧件塑性变形,辊系变形向轧件变形提供出口厚度分布,轧件变形向辊系变形提供轧制力横向分布,两者相互迭代求得厚度分布结果。结合现场实际,验证了模型的准确性,为在线计算出口辊缝提供了思路和依据。     

板宽对4辊CVC热轧机板形控制能力的影响

采用流面条元法分析带材的三维塑性变形，影响系数法分析辊系的弹性变形，并将二者耦合，建立了4辊轧机板形和板凸度的分析计算模型，并针对板宽对4辊CVC热带钢轧机板形控制能力的影响进行了仿真研究。仿真结果表明，随着板宽的增加，出口板凸度先增大后减小，辊缝变得越来越平缓；单位宽度辊间压力增大，且沿横向的变化比较均匀；板带的宽展减小。对热带钢轧制，乃至厚板轧制具有重要的意义。     

型钢生产中轧制压力模型的研究

针对型钢生产中轧制压力计算存在的难点,在板带轧制理论基础上,通过引入考虑三维的、不均匀变形的应力状态因子,并根据现场轧制压力产测值的回归分析,建立了型钢轧制压力统计模型。     

热轧轧制压力横向分布规律及预测模型

 轧制压力横向分布规律对快速轧辊轧件一体化模型的建立、轧辊磨损及辊形预测具有重要的意义。为简洁有效地描述轧制压力横向分布,提出了轧制压力横向分布表征指标,即边中比、高次程度、一次非对称度及三次非对称度。通过有限单元法建立了轧件三维弹塑性变形模型,并根据实测数据对模型边界条件进行设置,研究了不同因素影响下的轧制压力横向分布规律。考虑到各生产因素对轧制压力横向分布的影响不完全独立,不易获得函数表达式,以多组工况下有限元仿真结果为基础,建立多生产因素影响下的轧制压力横向分布人工神经网络预测模型,为轧辊轧件一体化快速计算模型的建立奠定了基础。     

带夹层不锈钢复合板异步轧制力数学模型研究

 为实现带夹层复合板异步轧制力的预报,对直接添加薄板作为中间层的不锈钢复合板进行受力分析,依据各层金属变形特点以及轧件摩擦力方向的变化,将轧制变形区划分为5个分区,考虑复合板单元体截面法向应力与剪应力在各层金属间的线性分布,借助各个分区力平衡方程,建立了带夹层复合板异步轧制力数学模型;研究了剪切屈服应力比、辊径比、摩擦因数比对各层单元体应力分布的影响以及不同压下率下中性点和连接点的位置变化规律;运用MSC.Marc有限元仿真软件,对316L/Ni/EH40复合板进行了5道次异步轧制仿真,轧制变形区受力状态与理论模型基本一致,各道次轧制力大小与理论计算值误差在10%以内,结果表明,本模型可为带夹层复合板异步轧制力精准预报提供理论指导。     

纵筋板轧制能量法解析三维模型的研究开发

针对纵筋板轧制具有局部严重畸变及兼有板带和型钢变形特征,提出了利用能量法解析纵筋板轧制过程的三维模型,能量法解析探索了一条新途径,解决了这类具有局部严重畸变的问题,并计算了轧制时的力能参数和变形参数,理论计算与实测结果相比较,轧制力计算值稍大于实测值,相对误差为0．3％－1．6％。     

Stream Surface Strip Element Method and Simulation of Three-Dimensional Deformation of Continuous Hot Rolled Strip

A new method, the stream surface strip element method, for simulating the three-dimensional deformation of plate and strip rolling process was proposed. The rolling deformation zone was divided into a number of stream surface (curved surface) strip elements along metal flow traces, and the stream surface strip elements were mapped into the corresponding plane strip elements for analysis and computation. The longitudinal distributions of the lateral displacement and the altitudinal displacement of metal were respectively constructed to be a quartic curve and a quadratic curve, of which the lateral distributions were expressed as the third-power spline function, and the altitudinal distributions were fitted in the quadratic curve. From the flow theory of plastic mechanics, the mathematical models of the three-dimensional deformations and stresses of the deformation zone were constructed. Compared with the streamline strip element method proposed hy the first author of this paper, the stream surface strip element method takes into account the uneven distributions of stresses and deformations along altitudinal direction, and realizes the precise three-dimensional analysis and computation. The simulation example of continuous hot rolled strip indicates that the method and the model accord with facts and provide a new reliable engineering-computation method for the three-dimensional mechanics simulation of plate and strip rolling process.     

板带轧制变形区金属出口横向位移函数的能量法修正

通过引入修正系数ｍ，修正变分法求解辊缝中金属横向流动得出的出口横向位移函数式中的Ｋ和Ｎ值，以使变形区金属出口横向位移分布接近实际，从而能较准确计算前，后张力的横向分布。ｍ用最不能量原理确定。修正后，前，后张力横向分布的计算值与实测结果基本吻合。     

Three-Dimensional Model for Strip Hot Rolling

Steel stripis widely usedin many fields such asautomobile ,building,transportation and householdappliance ,etc·. Withthei mprovement in productiv-ity and automation of strip processing,the require-ments for crown and flatness of strip have been in-creasingly severe ,and“crown free”steel strips arerequired for some special applications such as for au-tomobile parts andtinplate cans .In order toi mprovethe strip quality , an effective three-di mensionalmodel is needful to further study on the…     

A 3-D Differential Method for Solving Rolling Force of PC Hot Strip Mill

 According to the character of the deformation zone on pair cross rolls, which is different from the regular 4-high mill, there are longitudinal and transverse two-way shear deformation in the deformation zone, the character of metal particles flowing velocity is more complicated than normal rolling. Comprehensive influences of normal stress and shear stress in rolling direction, width direction and thickness direction are considered. Establish the rolling force calculation model of PC hot strip mills. After the longitudinal and transverse discretization of deformation zone, the longitudinal and transverse distribution of rolling force is worked out by the differential method, then calculate total rolling force. Calculated results are verified by experimental data.     

Nonlinear Finite Element Analysis of Thin Strip Temper Rolling Process

 To reveal the basic deformation mechanisms under the conditions of high friction, small reduction, and long contact length in thin strip temper rolling process, an elastoplastic finite element analysis of plane strain upsetting was made based on the FEM software Marc. The results indicated that a near flat ‘zero reduction’ region was present in the center of the contact arc. The simulation results about the effect of rolling parameters on the central flat region showed that any change of increasing the rolling force could result in or enlarge the central flat region in the deformation zone. Stress distribution results illustrated that the metal was in triaxial compression state. Although the maximum and minimum principal stresses were all much larger than the yield stress of the strip, the equivalent stress became lower than that, and no further plastic strain, even a small elastic spring back occurred in the central flat region. That was the problem of ‘hydrostatic pressure’ in thin strip temper rolling.     

B3 Spline Function Method Used in Simulating Flatness and Profile of Cold Rolled Strip

Flatness and profile are important quality indexes of strip. Combining the influence function method to solve the elastic deformation of roll system with the variational method to solve the lateral flow of metal, the flatness and profile of the strip during cold eontinuous rolling were simulated. The B3 spline funetion was used to analogize the lateral distribution of strip thickness. The transverse distributions of the exit thiekness and the front tension stress for eaeh pass were obtained. Compared with the measured results, it is proved that using the spline funetion to analogize the lateral distribution of strip thickness ean improve the ealculation accuraey of flatness and profile largely.     

一种改进的板带在线控制算法的研究

为了提高板带轧制力的计算速度和计算精度,提出了离散块元法。该法是将变形区划分为有限离散单元,考虑剪切变形作用,经BP神经网络训练获取其各种工况下的剪切变形因数模型而建立的高速计算模型,在平面变形条件下实现了对板带轧制力的预测,经该方法建立的轧制力计算模型具有较高的计算精度和计算速度,并在现场中得到了应用。