Void-shape effects on strength properties of nanoporous materials. (December 2017)

• Record Type: Journal Article
• Authors: Brach, Stella; Cherubini, Stefano; Kondo, Djimédo; Vairo, Giuseppe
• Is Part Of: Mechanics research communications. Volume 86(2017)
• Page Start: 11
• Page End: 17
• Publication Date: 2017-12
• Subjects: Strength properties -- Void-shape effects -- Nanoporous materials -- Molecular Dynamics; Mechanics, Applied -- Periodicals; Mécanique appliquée -- Périodiques; Mechanics, Applied; Periodicals; 530
• DOI: 10.1016/j.mechrescom.2017.10.009
• Languages: English
• ISSNs: 0093-6413

Abstract

Highlights: Strength properties of spheroidal-nanovoided single-crystal samples are numerically investigated. Prolate, oblate and spherical void shapes are considered. Several mechanical loadings, including axisymmetric and shear strain-rate states are applied. Void-shape effects induce a weakening of the computational sample as the void aspect-ratio is varied. Strength measures highly depend on the hydrostatic, second- and third-order deviatoric stress invariants. Abstract: In this paper, strength properties of nanoporous materials with spheroidal nanocavities are investigated via a Molecular Dynamics approach applied to a nanovoided aluminium single crystal, in the case of a fixed porosity level, and for prolate, oblate and spherical void shapes. Estimates of the effective strength domain are provided, by considering several mechanical loadings including axisymmetric and shear strain-rate states. Void-shape effects are quantified for different values of the void aspect ratio, mainly resulting in an overall weakening of the sample as the spheroidal nanovoid assumes either an oblate or a prolate shape, in comparison to the case of a spherical void. Finally, it is observed that the computed strength profiles exhibit the following specific features: (i) a strong dependence on the hydrostatic, second-order and third-order deviatoric stress invariants, (ii) more significant void-shape effects for triaxial-expansion stress states with a small hydrostatic component, and (iii) a more pronounced influence of the spheroid shape, as the aspect ratio is varied, in the presence of an oblate nanovoid rather than of a prolate one.