Self-stresses and Crack Formation by Particle Swelling in Cohesive Granular Media

Moulay Saïd El Youssoufi (1) , Jean-Yves Delenne (2) , Farhang Radjai (1)

1 PMMG - Physique et Mécanique des Milieux Granulaires
2 LMGC - Laboratoire de Mécanique et Génie Civil

We present a molecular dynamics study of force patterns, tensile strength and crack formation in a cohesive granular model where the particles are subjected to swelling or shrinkage gradients. Non-uniform particle size change generates self-equilibrated forces that lead to crack initiation as soon as strongest tensile contacts begin to fail. We find that the coarse-grained stresses are correctly predicted by an elastic model that incorporates particle size change as metric evolution. The tensile strength is found to be well below the theoretical strength as a result of inhomogeneous force transmission in granular media. The cracks propagate either inward from the edge upon shrinkage and outward from the center upon swelling.

Mots clés: granular media; porous media; cohesion; shrinkage; swelling; rupture

Domaines: Mécanique des matériaux [physics.class-ph]; Matière Molle [cond-mat.soft]; Science des matériaux [cond-mat.mtrl-sci]

Moulay Saïd El Youssoufi, Jean-Yves Delenne, Farhang Radjai. Self-stresses and Crack Formation by Particle Swelling in Cohesive Granular Media. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, 2005, 71, pp.051307. ⟨10.1103/PhysRevE.71.051307⟩. ⟨hal-00003083⟩