O形管辊弯成型有限元仿真与孔形优化设计

根据O形管成型的轧辊配辊方案和辊弯成型的机组参数,建立了符合实际工况的有限元仿真模型,并应用ABAQUS进行了全流程成型仿真;通过仿真成型截面和长边中点在Y方向位移量的分析,采用减小圆角区域与长边接触区域的孔形尺寸和增加X方向的孔形尺寸的方案对原轧辊的7~10道次的孔形进行了优化设计;对优化后的方案进行了仿真分析和生产验证。结果表明:有限元仿真能够预测辊弯成型的生产缺陷,并能对轧辊孔形设计提供有益的参考。     

基于计算机视觉的辊弯成型应变测量系统研究

介绍了辊弯成型板料应变测量系统的结构和基本原理,分析了不同网格制作方法的特点,提出了适合板料成型应变计算机视觉测量的方网格计算方法.通过与mse.marc仿真结果进行比较,验证了系统的有效性.     

高强度钢辊弯成型回弹分析

随着计算机性能的提高,试制成本的降低也带动了板料成形费用的降低.现在,在真正的金属成型生产之前,应用计算机对成型过程完全仿真,可优化成型的条件.成型预测技术发展过程中,在成型包括先进高强度钢内的许多金属出现了回弹问题.回弹是一种内部应力释放的过程,它对金属成型的精度有很大影响.尤其对一些加工硬化明显的材料,如高强度钢,回弹成为金属成型仿真的难点问题.本文对辊弯成型中使用高强度钢时回弹做了初步的有限元仿真分析,得出模型参数对回弹影响的基本规律.     

汽车覆盖件冲压成型的计算机仿真

介绍了板料成型CAE软件DYNAFORM,阐明了板料冲压成型有限元模拟的一般步骤。结合汽车覆盖件车门外门板的冲压成型仿真预测了可能出现的缺陷,根据仿真结果分析并制定了有效的预防措施。     

矿用W钢带多道次辊弯成型数值仿真

矿用W钢带作为一种新型的支护材料,与锚杆结合广泛用于矿井下巷道工作面、切眼、峒室及其他不稳定围岩。随着有限元理论研究的深入,运用弹塑性有限元法,采用大位移和大变形理论,对辊弯成型过程的数值模拟与分析。通过计算得到了矿用W钢带的尺寸参数,基于非线性有限元Marc建立了W钢带成型模型,对其多道次辊弯成型进行了仿真模拟分析,并与实际比较,验证了数值模拟的可靠性。重点分析了钢带成型时弯角处的应力应变,回弹,各道次板宽变化,摩擦系数和辊压力等关键问题,为W钢带成型提供理论依据,对多道次辊弯成型具有一定的参考价值。     

辊弯成型数值研究综述及全流程仿真关键问题

综述了辊弯成型数值研究的现状 ,总结了半解析法、有限条法、有限元法 3种研究方法的应用情况。指出动态显式有限元方法是建立辊弯成型全流程仿真系统的有效手段 ,并对其中的关键问题包括算法选择、引入各向异性和包辛格效应的材料本构模型、板带皱曲预示、接触回弹、轧辊强度校核等进行了探讨。     

基于ANSYS的槽钢辊弯成型过程有限元分析

通过有限元软件ANSYS/LS-DYNA对槽钢辊弯成型过程建立有限元模型,分析该过程中应力、应变和位移场情况,得到了槽钢在该过程中的变形特点和规律。研究结果为冷弯型钢产品的开发、孔型的设计等问题提供了预测模型,是对辊弯成型理论的补充,可以作为生产实践的有益参考。     

基于CCD的应变测量系统在辊弯成型中的应用研究

介绍了自行研制开发的CCD应变测量系统基本原理。通过辊弯成型试验,并与msc．marc有限元仿真结果进行比较,验证了结果的有效性,为辊弯成型应变测量提供了一种可行的的方法。     

直缝焊管辊弯成形动力学仿真研究

基于显式动力学算法,建立了直缝焊管成形过程的弹塑性有限元模型,采用大型非线性有限元软件ABAQUS对直缝焊管辊弯成形过程进行了模拟仿真。分析了成形过程中带钢的应力、应变的变化规律以及机架间距对成型质量的影响。研究结果表明,整个成型过程应力变化平缓,带钢边缘应变小于中部应变;随着机架间距的增大,带钢边缘的纵向应变相应减小。     

高频感应弯板成形试验台设计

针对国内外高频感应弯板成形试验设备缺乏现状,设计了弯板成形试验台,用于进行高频感应弯板成形试验,进而有助于研究高频感应弯板成形规律。利用Ansys软件对弯板成形模型进行了有限元分析,并利用试验台进行了相同参数下板料成形试验,将有限元分析得到的折弯角度曲线与试验得到的实际折弯角度曲线进行了对比,结果表明:有限元分析得到的板料折弯角度曲线与试验得到的板料折弯角度曲线基本相同,二者折弯角度偏差小于12.1%。     

箔带轧制的三维接触有限元分析

基于对三维多体接触问题有限元混合法基本原理及接触面的定解条件和判定条件的分析 ,本文将箔带轧机辊系及轧件组成的辊带系统视为三维多体接触问题 ,建立了接触有限元分析模型。对某厂四辊铝箔轧机初轧工况进行了数值计算 ,求得了辊缝内轧制压力的真实分布规律 ,充分揭示了箔带轧制过程中非轧制辊面存在压靠的事实。最后 ,针对来料板凸度对轧件板形的影响进行了有限元仿真分析 ,得出了与轧制规程图分析法一致的结论     

Analysis of the roll hunting force due to hardness in a hot rolling process

A hot rolling operation is performed to alter the thickness of a metal by passing the material through a pair of rollers, forming a gap that is somewhat narrower than the thickness of the material. Therefore, the quality of the product is a function of the pressure applied by the rollers. However, in this process, a roll hunting force occurs in which the rolling force is irregularly changed during the rotation of the rollers due to various complex mechanisms, which include roll surface hardness, difference in rotational speed between rolls, heat treatment conditions, and roll wear. In this study, roll wear tests were conducted to analyze the roll hunting force caused by variation in the hardness of the work roll. The friction coefficient of the work roll was then examined based on hardness. Then, a two-dimensional finite element model was constructed to investigate the roll hunting force as a function of the change in friction coefficient of the work roll. This finite element model was verified in relation to the theoretical rolling expression. Finite element model analysis was performed for three friction coefficients, and the effect of the roll hunting force was determined based on the reduction ratio and temperature. In addition, the wear depth of the work roll by the hardness was predicted. The influence of the abrasion of the work roll on the hunting force was analyzed.

     

成形法制备半蜂窝波形条的有限元模拟

航空工业上采用的以成形法成形半蜂窝波形条的方式,成形的波形条结构均匀、精度高、工艺间单.根据某厂生产波形条的工艺,利用非线性有限元法开发了成形法的有限元模型,运用该模型对现场的实际成形过程进行仿真计算,得到与现场实测相吻合的结果.比较板坯在单、双主动辊加栽的条件下,成形结果的优劣性.在此基础上,对影响成形结果的主要因素进行分析.     

Simulation and experimental verification of flexible roll forming of steel sheets

Roll forming is a sheet metal forming process that has been used for decades. Usually roll-formed sections have a constant cross section. Flexible roll forming is a brand new forming process that produces parts with variable cross sections, in which the rollers translate back and forth in a direction that is perpendicular to the sheet feeding direction. Theoretical analysis gives an explanation of the plane strain state, compressive stresses, tensile stresses, and shear stresses in flexible roll forming. In order to analyze the mechanics and the deformation characteristics of flexible roll forming, the finite element method (FEM) model of a 17-step flexible roll forming process is established. The yield criterion used in the FEM simulation is Hill 48, and the parameters of which are solved with the yield stresses under different loading conditions and are firstly verified with a plane strain tensile test. The complicated roller paths are realized with data extracted from the computer-aided design (CAD) files with VC++ programs developed by the authors. We developed the first flexible roll forming prototype machine in China, with which the roll forming experiment of a side door beam is performed. Final shapes of the experimental and numerical results are compared. It is shown that the numerical results based on Hill 48 yield criterion that is solved with yield stresses agree well with the experimental results, which indicates that the simulation model can well reflect the real forming process. Detailed analysis of the distribution and history of plastic strain, longitudinal strain, shear strain, and thickness of both the constant cross section and the variable cross section is performed, which is of great help to understand this forming process.     

铝带坯连续铸轧过程热力耦合有限元分析

根据铝带坯连续铸轧过程瞬态凝固、流变成形的特点,同时考虑影响辊套与铸坯传热界面的接触热导问题,建立了铝带坯连续铸轧过程热力耦合有限元分析模型。在对AN SYS有限元分析软件进行二次开发的基础上,探索了适合于铝带坯连续铸轧这一复杂多重非线性问题热力并存耦合分析的途径,得到了铝带坯连续铸轧过程的温度场及应力-应变场的分布规律。仿真分析结果与实测结果进行了对比分析,二者基本相符。     

Local deformation in roll forming

In a previous paper, a simple model was developed to extend the application of the traditional flower pattern diagram as a design tool for roll forming. The position of a point on the strip as it passes through each set of rolls can be identified as a series of points in the two-dimensional flower pattern diagram. In three dimensions, these points will lie on a non-circular cylindrical surface having its axis parallel to the machine axis. Assuming that these points are joined by a smooth curve, the forming path of a point on the strip as it passes through the roll forming process can be obtained as a plane curve on the plane development of this surface. It was shown in previous work that the longitudinal membrane strain and, in certain cases, local curvature of the sheet are functions of the slope of this plane curve. In this work, the strains on both surfaces at the edge of a strip in the forming of a simple V-channel are measured using strain gauges. It is shown that near the point of contact with the rolls, the strains differ by nearly an order of magnitude from those determined from the simple model which assumes that the trajectory is a smooth curve. A modification of the forming path is obtained from the measured bending strains. Although the changes in displacement are small, the peak values of strain near the point of roll contact are large and a consequence of highly localised changes in the forming path as the strip passes over each roll. Measurement of this perturbation in the forming path is difficult as the region is obscured by the forming rolls. The technique described here permits the reconstruction of this path and identifies a new area of investigation of longitudinal strains in roll forming. These are often associated with shape defects such as bow, warping and end flare.     

VC轧辊的承载特性研究

对控制压力与轧制力共同作用下的VC(variable crown)轧辊的承载特性进行了研究。基于所开发的VC轧辊系统,分析了辊缝形状和辊缝凸度与轧制力及控制压力的关系,提出了临界最大控制轧制力的概念。研究结果表明:当轧制力小于轧辊系统的最大临界控制轧制力时,其板形控制能力优于同规格的实心平辊;当控制压力较大且轧制力较小时,轧辊系统可以实现零凸度或负凸度的负载辊缝。     

宽带钢六辊冷连轧机横向刚度特性研究

板带轧机的横向刚度对于板形控制十分重要,研究轧机不同状态下的横向刚度变化规律对于实现板形的精确控制具有重要意义。本文针对某厂六辊轧机利用有限元软件ANSYS9.0建立了三维辊系有限元分析模型,分别分析了不同工作辊窜辊和中间辊窜辊下的轧制力横向刚度和弯辊力横向刚度的变化情况,为轧机板形控制量的调整提供了参考依据。     

小型专用拉弯矫直机的设计与工艺研究

镀锌薄钢带经常大量应用于冷弯型钢生产中,而在其生产过程中很容易出现板形缺陷。常见的辊式弯曲矫直设备通过单纯弯曲变形对钢带实施矫直,但无法胜任薄带复杂板形的矫正。拉伸弯曲矫直方法将拉伸和弯曲两种矫直工艺相结合,改变了钢带中性层的位置,经过多次拉直、弯曲能够实现钢带全截面延伸,能够同时实现钢带侧弯、波浪变形、坯料楔形等不良板形的矫直。为此我们开发了一种专门用于冷弯生产的小型拉弯矫直设备实现薄钢带的矫直功能。不但详述了设备机械、电气的研制与开发,而且采用有限元分析和现场试验相结合的方式,对特定产品的拉弯矫直工艺进行了研究。