面内異方性降伏条件の実験的考察

抄録

To examine the validity of three yield criteria with planar anisotropy [i.e., Hill's (1948) quadratic, Gotoh's biquadratic and Hill's (1990) nonquadratic criteria], commercial-purity aluminium and deep-drawing-quality steel sheets are tested in uniaxial tension and uniaxial (through thickness) compression. For Hill's criteria, two cases are considered here : (1) the material parameters are mainly evaluated by using γ-values, and (2) the material parameters are mainly evaluated by using yield stresses. Both the experimental γ-value and uniaxial yield stress versus orientation relationships are fairly well predicted by Gotoh's criterion. Hill's 1990 criterion for case (2) gives a more accurate fit to the experimental results of yield stress than the earlier quadratic criterion for case (1). However, the new Hill criterion for case (2) does not fit the corresponding values of γ versus orientation very well.