Problem neujednačenosti rezultata eksperimentalnog određivanja eksponenta deformacionog ojačavanja karoserijskih limova

Abstract

The paper contains a comparative presentation of eight different experimental methods for determination of strain-hardening exponent ("n" value) of steel sheets. There are 3 groups of methods. First-the measuring of maximal homogenous strain; second-the methods based on determining of two values of true stress and sorresponding plastic strain; third-the measuring of strains on a special specimen. All the methods use uniaxial tensile test. Special attention was paid to computer data acquisition system intended for determination of strain-hardening curves, mechanical properties and "n" value. Accuracy problem was treated wit intention of suggesting appropriate method for determination of this important value.