Title: On the differences of dynamic localisations between different types of metals

Authors: Farid Abed

Addresses: Department of Civil Engineering, College of Engineering, American University of Sharjah, P.O. Box 26666, Sharjah, UAE

Abstract: This paper presents a numerical study of inelastic localisations in metals after utilising a thermodynamically consistent framework of viscoplastic formulation implemented into a commercial finite element code. The significance of using physically-based flow stress relations, instead of empirical relations, is examined by considering three microstructure-based constitutive equations developed previously for three different crystal types of metals. The same numerical values of material constants are used with a range of loading initial temperatures and velocity impacts. Differences of dynamic localisations between three body-centred cubic metals (niobium, tantalum and vanadium), one fcc metal (OFHC copper) and one hcp metal (titanium) are illustrated and discussed through studying the initiation and propagation of necking and shear bands in a circular bar and simple tension plane strain problems, respectively. Moreover, the effect of initial temperatures and strain rates on dynamic localisations is also scrutinised. Objective results using different mesh configurations are verified as a result of including viscosity in the constitutive models.

Keywords: dynamic localisation; necking; shear bands; viscoplasticity; finite element method; FEM; simulation; temperature; strain rate; constitutive relations; inelastic localisations; metals; microstructure; niobium; tantalum; vanadium; OFHC copper; titanium; viscosity.

DOI: 10.1504/IJMSI.2010.035207

International Journal of Materials and Structural Integrity, 2010 Vol.4 No.2/3/4, pp.215 - 237

Published online: 14 Sep 2010 *

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