Quantification of large and localized deformation in granular materials

Fu, P; Dafalias, YF

dc.contributor.author	Fu, P	en
dc.contributor.author	Dafalias, YF	en
dc.date.accessioned	2014-03-01T02:12:04Z
dc.date.available	2014-03-01T02:12:04Z
dc.date.issued	2012	en
dc.identifier.issn	00207683	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/30003
dc.subject	Deformation	en
dc.subject	Discrete element method	en
dc.subject	Granular material	en
dc.subject	Rate of deformation	en
dc.subject	Shear band	en
dc.subject	Strain	en
dc.subject	Velocity gradient	en
dc.subject.other	Biaxial compressive tests	en
dc.subject.other	Engineering strains	en
dc.subject.other	Equivalent continuum	en
dc.subject.other	Granular assembly	en
dc.subject.other	Heterogeneous distributions	en
dc.subject.other	Large deformations	en
dc.subject.other	Localized deformations	en
dc.subject.other	Novel concept	en
dc.subject.other	Nucleation process	en
dc.subject.other	Numerical example	en
dc.subject.other	Particle-based simulation	en
dc.subject.other	Rate of deformation	en
dc.subject.other	Shear band localizations	en
dc.subject.other	Shear banding	en
dc.subject.other	Sub-domains	en
dc.subject.other	Velocity gradients	en
dc.subject.other	Continuum mechanics	en
dc.subject.other	Finite difference method	en
dc.subject.other	Granular materials	en
dc.subject.other	Shear bands	en
dc.subject.other	Strain	en
dc.subject.other	Deformation	en
dc.title	Quantification of large and localized deformation in granular materials	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.ijsolstr.2012.03.006	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.ijsolstr.2012.03.006	en
heal.publicationDate	2012	en
heal.abstract	Quantifying large deformation in granular assemblies using concepts originating from continuum mechanics is a challenging task because of (1) the discontinuous nature of granular displacement, which does not allow the definition of a continuum measure of deformation, and (2) the almost inevitable shear band localization. These problems exist in both real-world granular materials and their numerical idealizations using particle-based simulations. In this work a new method is developed in order to address these issues. Instead of creating a meshed equivalent continuum for quantifying small engineering strains, the new method performs independent random queries on the velocity gradient characteristics of arbitrary sub-domains in the assembly through the novel concept of overlapping reference triangles, thus, enabling rigorous handling of large deformations which are usually associated with localization. The proposed method is illustrated and validated by discrete element method (DEM) simulation of a biaxial compressive test, in which apparent shear banding takes place. The homogenized deformation quantifications based on the new method match the estimations from the imposed boundary conditions. The numerical examples are also applied to (1) quantifying the heterogeneous distribution of deformation over the specimen, (2) visualizing the nucleation process of shear bands, and (3) characterizing shear flow patterns in shear bands. An investigation on the effects of the reference triangle sizes yields some inspiring and practically significant results. © 2012 Elsevier Ltd. All rights reserved.	en
heal.journalName	International Journal of Solids and Structures	en
dc.identifier.doi	10.1016/j.ijsolstr.2012.03.006	en
dc.identifier.volume	49	en
dc.identifier.issue	13	en
dc.identifier.spage	1741	en
dc.identifier.epage	1752	en