Effect of cruciform specimen design on strain paths and fracture location in equi-biaxial tension

Abstract Hot stamping technologies require new methods for evaluating formability of sheet metal under various forming conditions. Biaxial tensile testing method using a cruciform specimen has been used the applications, but suitable design not yet accepted. One challenges in designing tests is to ensure proportional equi-biaxial strain paths arise at location fracture initiation. In this study, after reviewing existing designs, three different geometries specimen, named Type I, II and III, were proposed. Using numerical analysis practical experiments, initiation locations corresponding specimens investigated tension. Numerical simulations performed optimise dimensions I achieve relatively high level near centre point specimen. Based on optimised dimensions, carried out with geometries, compared analysed. It was found that all specimens, state appears only point. never initiates point, fillet transition zone where major higher than The III have ability initiate produce ratio ? close 1 tension, 0 plane-strain -0.5 uniaxial tension research provides design, which potential be metal.