Forming Limit Curves for Complex Strain Paths

Archives of Metallurgy and Materials

D. Lumelskyy¹  R. Pęcherski¹  J. Rojek¹  W. Chorzępa²  M. Tkocz³  F. Grosman³ 

[1] Institute of Fundamental Technological Research, Polish Academy of Sciences Pawinskiego 5b, 02-106 Warsaw, Poland;Kirchhoff Polska sp. Z o.o., Wojska Polskiego 3, 39-300 Mielec, Ppoland;Silesian University of Technology, Krasinskiego 8, 40-019 Katowice, Poland

关键词: Keywords : sheet forming;    formability;    forming limit curve;    complex strain-path;   

DOI  :  10.2478/amm-2013-0042

学科分类：金属与冶金

来源: Akademia Gorniczo-Hutnicza im. Stanislawa Staszica / University of Mining and Metallurgy

【 摘 要 】

This paper presents results of experimental studies of forming limit curves (FLC) for sheet forming under complex strain paths. The Nakazima-type formability tests have been performed for the as-received steel blank and for the blank pre-strained by13%. Prestraining leads to abrupt change of strain path in the blank deformation influencing the forming limit curve. The experimental FLC of the pre-strained blank has been compared with the FLC constructed by transformation of the as-received FLC. Quite a good agreement has been found out. The concept of strain-path independent FLCs in polar coordinates has been verified. Two types of the polar diagrams have been considered, the first one with the strain-path angle and effective plastic strain as the polar coordinates, and the second one originally proposed in this work in which the thickness strain has been used instead of the effective plastic strain as one of the polar coordinates. The second transformation based on our own concept has given a better agreement between the transformed FLCs, which allows us to propose this type of polar diagrams as a new strain-path in dependent criterion to predict sheet failure in forming processes.

【 授权许可】

Unknown