Bernard Cambou is an Engineer from Ecole Centrale de Lyon, Ph.D. He holds the position of State University Professor and is a former director of the Civil Engineering Department. He is Professor within the teaching department of Solid Mechanics, Mechanical Engineering and the Laboratory of Tribology and Systems Dynamics, UMR CNRS 5513, École Centrale de Lyon.Hélène Magoariec is a Doctor of Engineering in solid mechanics, and lecturer at the Ecole Centrale de Lyon. She is a graduate of the Ecole Centrale de Marseille in 2000 and a doctorate in mechanical engineering from the University of Aix-Marseille II in 2003. In collaboration with the University of Aachen, she joined the Ecole Centrale de Lyon in 2005 and joined the Laboratory of Tribology and System Dynamics (LTDS). Her research activities concern the micromechanics of heterogeneous media, applied to different materials to suit her projects and collaborations, such as metal composites, granular, semi Drivers and since 2010, biological tissues.Ngoc-Son Nguyen's research interests lie in the field of mechanics of granular materials; these include Computational mechanics, numerical modeling in DEM, multi-scale approach and homogenization technique, shock dynamics and nonlinear wave propagation. He received his PhD in civil engineering in 2009. Since 2010, he has undertaken research at INRIA, Grenoble.

1: Previous Approaches and Motivation for the Use of the Meso-scale

2: Definition of a Meso-scale for Granular Materials

3: Texture, Stress and Strain at the Meso-scale

4: Texture-Stress-Strain Relationship at the Meso-scale

5: Change of Scale Based on Phenomenological Modeling at the Meso-scale

Granular Materials at Meso-scale: Towards a Change of Scale Approach proposes a new way for developing an efficient change of scale-considering a meso-scale defined at the level of local arrays of particles. The change of scale is known to be a very interesting way to improve the modelling of mechanical behavior granular materials. In the past, studies have been proposed using a micro-scale at the grain level to perform change of scale, but limitations have been proven for these approaches.

Definition and analysis of the phases are detailed, constituted by sets of meso-domains sharing the same texture characteristics. The authors propose a local constitutive model for the phases, allowing the constitutive model of the representative elementary volume to be definied from a change-of-scale approach and, finally, presenting the validation of obtained modeling on cyclic loadings.