Determination of strain criterion of Portevin–Le Chatelier effect for aluminum alloy sheets
(1.北京市北京航空航天大学机械工程及自动化学院
2.School of Mechanical Engineering and Automation, Beihang University, Beijing 100083, China
3.Chengdu Aircraft Industrial Co Ltd, Chengdu 610092, China)
2.School of Mechanical Engineering and Automation, Beihang University, Beijing 100083, China
3.Chengdu Aircraft Industrial Co Ltd, Chengdu 610092, China)
Abstract: According to the deformation state in skin stretch forming, an experiment was investigated to determine the critical strain, which make the slip line occur, and the strain criteria under different strain paths are obtained. The uniaxial tension tests of different specimens were carried out to determine the critical strains of different strain paths. Then, the slip line limited curve(SLC) is available from these critical strains. Two kinds of aluminum alloys, 2024-T3 and 2524-T3, were studied, and two SLCs are gained. The application of the SLC to an airplane skin stretch forming simulation was investigated, and the results show that the SLC can be used to control the slip lines occurring in practice.
Key words: aluminum alloy; PLC effect; strain path; slip line limited curve(SLC); stretch forming; airplane skin