Determination Methods of Anisotropic Coefficient R-values of Sheet Metal and Its Evolution in Subsequent Yielding

doi:10.3901/JME.2022.06.091

Abstract

Abstract: The anisotropic coefficient R-value of cold rolled sheet metal is usually used as a constant to determine the anisotropic parameters of constitutive model. In order to improve the prediction accuracy of anisotropic constitutive model, the evolution of R-values must be considered. Taking low carbon steel plate as the research object, the applicable conditions and limitations of three existing methods for determining variable R-values are compared and analysed. On this basis, a reverse solution method for variable R-values is proposed, and the analytical models under the condition of quadratic function and exponential function are given. It is revealed that the significant difference of R-values calculated by different methods is caused by the calculation error of the slope of the strain curve. Considering the in-plane anisotropy of the sheet metal, based on the principle of equal plastic work, the evolution of R-values of DC04 with plastic work and angle is given. The results show that, for low carbon steel, the evolution law of R-values show a downward trend with the increase of uniaxial tensile plastic strain. In addition, the proposed method not only has high accuracy, but also has simple expression, which is more convenient for the secondary development and application of the constitutive model considering the anisotropic evolution in subsequent yielding.

Key words: cold rolled sheet metal, uniaxial tensile, anisotropic coefficient, anisotropy, constitutive model, subsequent yielding

CLC Number:

TG301

MU Zhenkai, ZHAO Jun, YU Gaochao, HUANG Xueying, SUN Honglei. Determination Methods of Anisotropic Coefficient R-values of Sheet Metal and Its Evolution in Subsequent Yielding[J]. Journal of Mechanical Engineering, 2022, 58(6): 91-100.

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