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Interaction of Void Spacing and Material Size Effect on Inter-Void Flow Localization

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Holte, I 
Srivastava, A 
Martínez-Pañeda, Emilio  ORCID logo  https://orcid.org/0000-0002-1562-097X
Niordson, CF 
Nielsen, KL 

Abstract

The ductile fracture process in porous metals due to growth and coalescence of micron scale voids is not only affected by the imposed stress state but also by the distribution of the voids and the material size effect. The objective of this work is to understand the interaction of the inter-void spacing (or ligaments) and the resultant gradient induced material size effect on void coalescence for a range of imposed stress states. To this end, three dimensional finite element calculations of unit cell models with a discrete void embedded in a strain gradient enhanced material matrix are performed. The calculations are carried out for a range of initial inter-void ligament sizes and imposed stress states characterised by fixed values of the stress triaxiality and the Lode parameter. Our results show that in the absence of strain gradient effects on the material response, decreasing the inter-void ligament size results in an increase in the propensity for void coalescence. However, in a strain gradient enhanced material matrix, the strain gradients harden the material in the inter-void ligament and decrease the effect of inter-void ligament size on the propensity for void coalescence.

Description

Keywords

micromechanics, plasticity

Journal Title

Journal of Applied Mechanics, Transactions ASME

Conference Name

Journal ISSN

0021-8936
1528-9036

Volume Title

88

Publisher

ASME International

Rights

All rights reserved