Abstract: Due to the in-plane anisotropy of the material, wavy earing defects occur during cup drawing. In order to accurately predict earing, in view of the limitations of the existing theoretical model only considering uniaxial compression deformation, on the basis of considering the biaxial stress state of the micro-body and the influence of radial non-uniform deformation, a new theoretical model for quantitative prediction of earing characteristics (including earing number, position and cup wall height) of cup-shaped parts is proposed. The accuracy of the theoretical model is verified by finite element analysis and experiments of deep drawing cup-shaped parts of 2219-O aluminum alloy sheet. The results show that the number of earings is the same as the maximum value of the in-plane anisotropic coefficients, the cup height increases monotonically with the anisotropic coefficient r_θ+90, the maximum and minimum positions of the cup height correspond to the maximum and minimum positions of r_θ+90. The maximum position of r_θ+90 corresponds to the earing peak, the minimum position corresponds to the earing trough. Comparing the earing characteristics under different initial blank diameters, the theoretically predicted earing number is exactly the same as the experiments, the position of the wave trough is exactly the same, and the position of the earing peak has a slight error, and the maximum error does not exceed 4°. The prediction accuracy of cup height and earing height is significantly better than that of the existing theoretical model, and the prediction accuracy has better consistency for initial blank with different diameters. The theoretical model does not depend on the constitutive model of the material, and can provide a reference for the study of cup earing.

Key words: ear, theoretical model, anisotropy, deep drawing experiment, 2219-O aluminum alloy