Extracting true stresses and strains from nominal stresses and strains in tensile testing

Abstract Seemingly a simple task, the extraction of flow curve (true stress vs. true plastic strain) from nominal stresses and strains in standard tensile testing still has its unsolved points. This study addresses two them: (i) materials without yield point phenomenon (or generally region homogeneous deformation), is typically calculated assuming constant volume, ignoring elastic volume changes. Here, we derive set exact analytical solutions for with remarkable simplicity beauty that fully account cross‐checked by finite element simulations as well zeroth‐ first‐order approximations; perfect agreement been found. (ii) In pronounced phenomenon, complicated three‐dimensional state inevitably arises at edge Lüders bands, which masks real inherent) material behaviour. To determine behaviour region, here use new macroscopic approach characterised high upper point, typical strain hardening common many materials, triaxiality develops edges bands determines level observed lower point. verified experiments (including video observations digital image correlation (DIC) distribution measurements) very good agreement.