Crystallographic texture, anisotropic yield surfaces and forming limits of sheet metals

Plastic behaviour and stretchability of sheet metals. Part II: Effect of yield surface shape on sheet forming limit

A simple isotropic-distortional hardening model and its application in elastic-plastic analysis of localized necking in orthotropic sheet metals

An improved analytical approach for determination of forming limit diagrams considering the effects of yield functions

This article addresses a theoretical analysis of the 'modified maximum force criterion' (MMFC) introduced by Hora et al (1996 A prediction method for ductile sheet metal failure in FE-simulation Proc. Numisheet'96 Conf. pp 252–6). In this work a computational framework for the MMFC is given and it will be shown that the MMFC contains an important singularity which emerges if the yield locus used in the necking simulation exhibits straight line segments and leads to singularities in the predicted forming limit curve or even in total failure in forming limit diagram prediction. It is shown that the singularity emerges in commercial sheet alloys and, therefore, the general reliability of the MMFC appears questionable. It is thus concluded that an extension of the MMFC is required in order to fix the singularity problem.

http://iopscience.iop.org/article/10.1088/0965-0393/12/4/009/pdf

S.N. Rasmussen

Papers

Effect of rounded vertices in the yield surface on localized necking in biaxially stretched sheets