Depending on the relative positions of voids and on the loading conditions, shear loading components can play an important role in the void coalescence process leading to ductile fracture. Yet, most void coalescence criteria including the original criterion of Thomason, and its various extensions/improvements, take only normal loads into account and neglect the contribution from shear loads to coalescence. Shear can affect both the stress/strain at the onset of coalescence and the direction of deformation localization. In this paper, first, the predictive capabilities of different coalescence criteria without shear effect are critically assessed and the expressions involved in the original Thomason criterion are fine-tuned by comparing with 3D finite element calculations performed on a unit cell containing a spheroidal void. Then, the improved Thomason criterion is theoretically extended - by using limit load analysis - to incorporate the effect of shear. The predictions of this new coalescence criterion are in good agreement with the reseults produced by 3D finite element calculations, for both loadings involving or not a shear component.
Affiliations
TOBB University of Economics and Technology, Ankara (Turkey)Department of Mechanical Engineering
Université Paris VIInstitut Jean-Le-Rond-d'Alembert
Tekoglu, C., Leblond, J.-B., & Pardoen, T. (2012). A criterion for the onset of void coalescence under combined tension and shear. Journal of the Mechanics and Physics of Solids, 60(7), 1363-1381. https://doi.org/10.1016/j.jmps.2012.02.006 (Original work published 2012)