论文部分内容阅读
A modified Swift type flow stress-strain relation is presented in order to describe the uniaxial tension test curve reasonably.The FLD-strain (forming limit diagram made up of limit strain) of 5754O aluminum alloy sheet is calculated under linear loading path based on two flow stress-strain relations using M-K instability theory.The Yld2000-2d yield function is used for the calculation of the FLD-strain.The material constants of the Yld2000-2d yield function are expressed as the functions of the equivalent plastic strain for describing the anisotropic deformation behavior more accurately.By comparing the theoretical and the experimental results, it is found that the calculated FLD-strain based on the modified Swift flow stress-strain relation can reasonably describe the experimental results.However, though the common Voce flow stress-strain curve can describe the deformation behavior under homogenous deformation phase accurately, the FLD-strain calculated based on it is obviously lower than the experimental results.It is conclude that the higher the hardening rate of sheet metal is, the higher the forming limit is.A method for determining the reasonable flow stress-strain relation for describing the material behavior under inhomogenous and the forming limit of sheet metal is recommended.