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Analysis of the effect of cohesion and gravity on the bulk behaviour of powders using Discrete Element Method

Moreno-Atanasio, R, Antony, SJ and Ghadiri, M (2004) Analysis of the effect of cohesion and gravity on the bulk behaviour of powders using Discrete Element Method. In: PARTECH, (Nurenberg). PARTECH 2004, International Congress for Particle Technology, 16-18 March 2004, Nuremberg, Germany. PARTECH, (Nurenberg) .

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Computer simulations using Distinct Element Method have been carried out to analyse the bulk behaviour of a polydisperse assembly of glass beads. For this purpose an assembly made of 3000 spheres were generated to which the mechanical properties of glass beads were assigned. The system was initially compressed isotropically at a strain rate of 1 s-1 in the absence of gravity and surface energy. Once the assembly reached a packing fraction of about 0.62, the effects of cohesion and gravity on the bulk behaviour were analysed for two different cases. In the first case only gravity was applied, whilst in the second case both gravity and surface energy were acting on the particles. The evolution of the components of the stress tensor for the case in which only gravity was applied indicated that the gravity did not appreciably affect the isotropy of the system. In contrast, the system in which surface energy was introduced became anisotropic. The concept of unconfined yield stress of bulk cohesive powders was used to analyse the effect of surface energy and strain rate. For values of surface energy of 1.0 J/m2 and of strain rate lower than 1 s-1 the unconfined yield strength did not change significantly indicating a quasi-static behaviour for the compression process. However, for values of strain rates larger than 1 s-1 the unconfined yield strength increased with the strain rate, following a power law trend with an index of 1.7.

Item Type: Proceedings Paper
Copyright, Publisher and Additional Information: Conference Proceedings published on CD-ROM. This can be ordered by sending an e-mail to partec@nuernbergmesse.de
Keywords: granular materials; Gravity effects
Institution: The University of Leeds
Academic Units: The University of Leeds > Faculty of Engineering (Leeds) > School of Chemical & Process Engineering (Leeds) > Institute for Particle Science and Engineering (Leeds)
Depositing User: Repository Officer
Date Deposited: 15 Mar 2006
Last Modified: 19 Sep 2014 09:47
Published Version: http://www.powtech.de/main/daz41ot4/dazdc3bt/page....
Status: Published
Publisher: PARTECH, (Nurenberg)
Refereed: No
URI: http://eprints.whiterose.ac.uk/id/eprint/1101

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