Biaxial tests on cruciform specimens for the validation of crystallographic yield loci

摘要

A biaxial tensile test has been designed for the experimental determination of yield locus points of thinsteel sheets. Using texture-based anisotropic finite-element (FE) simulations, the geometry of the testsample has been optimised and the accuracy of the conversion procedure has been validated. It wasfound that the present technique has a high precision for principal stress ratiosσ{sub}y/σ{sub}xbetween tan(20°) and tan(70°). Experimental tests have been carried out on five steel qualities(low and ultra-low carbon) with thickness between 0.8 and 1.5 mm. Both yield stresses and ratios ofplastic strains have been compared to the theoretical predictions obtained with the Taylor-Bishop-Hill (TBH) model using the experimentally determined crystallographic textures. The {110} <111>and {112} <111> slip systems were considered using both full-constraints (FC) and relaxed-constraints (RC) assumptions for the TBH model. These comparisons are clearly in favour of theTBH-FC model.