Prediction of complete forming limit diagram from tensile properties of various steel sheets by a nonlinear regression based approach

摘要

Experimental Forming Limit Curve (FLC) and tensile properties of various steel grades are collected from literatures to validate the proposed model. The experimental results show that the ultimate tensile stress (sigma(UTS)), total elongation (epsilon(t)), coefficient of normal anisotropy (r), tensile strain hardening exponent (n) and sheet thickness (t) are strongly related to the plane strain forming limit (FLC0) values for steel sheets. A nonlinear regression equation is proposed to predict FLC0 from uniaxial tensile properties like sigma(UTS), epsilon(t), r, n and t. To verify the predictive capability of the proposed equation, predicted FLC0 values for fifty six steel grades in various thickness and strength ranges are compared with experimentally measured FLC0 values. It is observed that the newly developed nonlinear regression equation predicts well the FLC0 values.