抄録
The nonlinear-defect model, which had been previously proposed to analyze fracture and residual strain theoretically, was applied to the real stress (σ)-strain (ε) curve of steel. The results obtained are as follows
(1) When it is assumed that the cross-sectional area decreases and the stress-ccncentration appears during the final fracture resulting from propagation of a visual crack, a σ-ε curve becomes similar to that of a nonlinear-defect.
(2) The three regions of strain in a σ-ε curve were analyzed and discussed. The equivalent defects in the initial region Ri should be different from those in the final region Rf, and at the character of equivalent defects in the transient region Rt should change from that in Ri to that in Rf. The σ-ε curve can be given as
ε{1-β(ε)ε}=A(ε)σ
where β and A are parameters characteristic of each region.
(3) The above expression represents quantitatively the actual σ-ε curve of steel.
