2009 Volume 50 Issue 1 Pages 138-144
A novel approach to determination of the true stress–strain relation in a post-uniform elongation range by finite element modeling has been proposed, on the basis of the variation of strain-hardening exponent (n) with strain during uniaxial tensile tests. The strain dependence of n-value can be expressed by a linear or simple quadratic function. The proposed method has been applied to several sheet metals with large differences in strain-hardening behavior. The finite element analytical results, obtained by using constitutive equations derived from a variation of n-value with strain, are in good agreement with the measured load–elongation curves. As the number of parameters is sufficient by two at the most, the optimization by an inverse analysis becomes very easy. It has been verified that the proposed method is effective to estimate the stress–strain curves of sheet metals in the post-uniform elongation range.