矩形截面型材拉弯弹复研究的实验新方法

以往的拉弯实验研究都是基于传统的拉弯成形机，设备造价高，操作复杂。本文以矩形截面型材为研究对象，基于弹塑性弯曲工程理论的基本假设和应变的可叠加原理构建了矩形截面型材拉弯的力学模型，讨论了拉弯变形后型材横截面上应力应变分布的不同情况，进一步揭示了拉弯成形的变形机理。设计了一种新型的拉弯实验模具并开展了矩形截面型材拉弯弹复的实验研究，针对某一矩形截面型材，在弯曲半径为200 mm和300 mm时，获取了型材回弹后的半径与截面拉力的关系。利用有限元分析软件ABAQUS开展了基于物理实验的有限元模拟分析，物理实验和有限元分析所获得的拉弯弹复规律与理论解析结果一致，数据吻合。该模具造价低廉，结构简单，操作方便。实验结果可靠，具有一定的理论研究和工程指导价值。

New experimental research method for stretch-bending springback of profile with rectangular cross-section

The past experimental research is usually based on the traditional equipment with high cost and complex operation.In this paper,the profile with rectangular cross-section is taken as research object.The mechanical models of profile stretch-bending are established based on the classical elastic-plastic theory and the characteristic of strain superposition.Different cases of stress distribution on the profile cross-section after stretch-bending deformation are discussed to reveal the deformation mechanism of stretch-bending.A new set of mold for stretch-bending experiments is designed and the experimental research on stretch-bending of profile with rectangular cross-section is carried out.The relationships between radius after springback and tensions are obtained when the bending radius are 200 mm and 300 mm.Based on the physical experiment,a finite element simulation analysis is carried out using software ABAQUS.The springback laws of stretch-bending obtained by experiment and finite element analysis are agreed well mutually.This experimental mold has advantages of low cost,simple structure and convenient operation.It will provide base for theoretical research and engineering practice.