Influence of Strain Gradient Hardening on Springback in Microbending Process of Metal Foils
In order to investigate the microbending behavior of pure aluminum foils, scaled experiments with thicknesses ranging from 25μm to 500μm were carried out. In the experiments, an increasing springback angle with decreasing foil thickness is observed, which indicates the obvious presence of size effects, and is attributed to strain gradient hardening. So a constitutive model, taking into account both strain and strain gradient hardening, is proposed to analyze the microbending process of thin foils. The model is based on the relationship between flow stress and dislocation density, originally proposed by Taylor, in which the material intrinsic length is also assumed to be related with dislocation density. The model is adopted to predict the springback angle after microbending by analytical expression. It is confirmed that the predictions by using the proposed hardening model agree with the experimental data, while those by using conventional elastoplastic model can not describe such size effects. Thus the proposed analytical equation can be helpful for the design of microbending processes of thin metal foils.
strain gradient plasticity microbending springback aluminum foils analytical equation
Li H.Z. Dong X.H. Shen Y. A.Diehl H.Hagenah U.Engel M.Merklein
National Die & Mold CAD Engineering Research Center, Shanghai Jiao Tong University, Shanghai, China Chair of Manufacturing Technology, University of Erlangen-Nuremberg, Erlangen, Germany
国际会议
2nd Asian Workshop on Macro/Nano Forming Technology(AWMFT-2009)(第2届亚洲微米纳米技术研讨会)
长沙
英文
602-606
2009-10-25（万方平台首次上网日期，不代表论文的发表时间）