• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2018, Vol. 54 ›› Issue (16): 108-117.doi: 10.3901/JME.2018.16.108

• 材料科学与工程 • 上一篇    下一篇

薄壁管材纯弯曲后截面残留扁化变形预测

张子骞, 颜云辉   

  1. 东北大学机械工程与自动化学院 沈阳 110004
  • 收稿日期:2018-01-10 修回日期:2018-04-09 出版日期:2018-08-20 发布日期:2018-08-20
  • 通讯作者: 张子骞(通信作者),男,1980年出生,博士,讲师。主要研究方向为金属塑性成型工艺与装备设计。E-mail:zqzhang@me.neu.edu.cn
  • 作者简介:颜云辉,男,1960年出生,博士,教授,博士研究生导师。主要研究方向为冶金产品表面质量监控与评价、装备可视化设计。E-mail:yhyan@me.neu.edu.cn
  • 基金资助:
    中央高校基本科研业务专项资金资助项目(N160304010)。

Prediction of Residual Cross-sectional Ovalization of Thin-walled Circular Steel Tubes under Pure Bending

ZHANG Ziqian, YAN Yunhui   

  1. School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110004
  • Received:2018-01-10 Revised:2018-04-09 Online:2018-08-20 Published:2018-08-20

摘要: 针对薄壁金属管材在塑性纯弯曲后横截面扁化变形难于准确预测的难题,运用四点纯弯曲试验,获得截面残留扁化量的实测数据,进而发现截面最大扁化量出现在垂直于轴向弯曲中性层的方向。随后基于图像处理技术与数据拟合方法,探索出可采用椭圆函数对截面轮廓进行近似数学描述。运用经典卸载理论构建薄壁管材纯弯曲后截面最大残留扁化量的预测模型。通过理论值与试验数据的比对证明了模型的正确性,并获得最大残留扁化量随弯曲半径、壁厚的变化关系。该理论模型能为提高薄壁管材塑性弯曲过程的成形质量提供有效途径。

关键词: 薄壁管材, 截面扁化, 塑性纯弯曲, 最大残留扁化量

Abstract: Cross-sectional ovalization usually occurs when thin-walled steel tube is subjected to large plastic bending. It is hard to predict the residual deformation of the cross-section when the external bending moment is removed. So four-point pure bending experiments involving eight stainless steel specimens with different geometric parameters under different bending radii are carried out to periodically monitor the cross-sectional flattening along the circular direction. From the experimental results it is observed that the appearance of the maximum residual flattening is usually found in the direction normal to the neutral surface. Then using the digital image processing methods the points on the outer edge in the image of the ovalised cross-section are fitted by the elliptic equation which is validated to be best in fitting prices. Finally a rational model for predicting the maximal residual section flattening of the thin-walled circular steel tube after pure bending is presented using the classic unloading rule. The new model is validated by experimental datum. The results show that the model agrees well with the experiments with less than 10% error. And based on the analytical results, the relationships between the residual flattening and the bending radius as well as the wall thickness are also revealed. This new model is expected to find its potential application in thin-walled steel tube bending operation.

Key words: cross-sectional ovalization, maximal residual cross-sectional flattening, plastic pure bending, thin-walled tube

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