Evolving texture-informed anisotropic yield criterion for sheet forming

Abstract

In this work we compare the predictions of the phenomenological anisotropic plane-stress plasticity model BBC2008, calibrated either classically by means of mechanical tests, or by crystal plasticity virtual experiments, to those of a HMS type model with continuous calibration of the same phenomenological model BBC2008. An industrial-grade aluminum alloy AA-6016 is chosen for the test case. Experimental part of the study includes tensile tests and deep drawing of cylindrical cups, preceded by measurements of crystallographic texture. It was found that the material exhibits a noticeable through-thickness gradient in terms of both the texture and plastic anisotropy. The classical calibration of the 16 parameters of BBC2008 was done from tensile experiments (yield stresses and Lankford coefficients) in directions every 15° from the rolling direction and the biaxial yield stress and anisotropy coefficient. The initial texture for the HMS-BBC2008 model was determined from as received samples. The ALAMEL model was used to estimate polycrystal plasticity from texture information. Finally, the earing number and height profile was measured for experimentally drawn cups and compared to the results of macroscopic simulations, based on both the classically calibrated BBC2008 model and the continuously calibrated HMS-BBC2008 model.