Using particle dynamics simulations, we investigate the strength and microstructure of agglomerates of wet frictional particles subjected to axial compression. The numerical model accounts for the cohesive and viscous effects of the binding liquid up to a debonding distance with the liquid assumed to be distributed homogeneously inside the agglomerate. We show that wet agglomerates undergo plastic deformation due to the rearrangements of primary particles during compression. The compressive strength is thus characterized by the plastic threshold before the onset of failure by the irreversible loss of wet contacts between primary particles. We find that the agglomerate plastic threshold is proportional to the characteristic cohesive stress defined from the liquid-vapor surface tension and the mean diameter of primary particles, with a prefactor that is a nearly linear function of the debonding distance and increases with size span. We analyze the agglomerate microstructure and, considering only the cohesive capillary forces at all bonds between primary particles, we propose an expression of the plastic strength as a function of the texture parameters such as the wet coordination number and packing fraction. This expression is shown to be consistent with our simulations up to a multiplicative factor reflecting the distribution of the capillary bridges. (C) 2018 Published by Elsevier Ltd.

VL - 92 UR - https://www-sciencedirect-com.libproxy.mit.edu/science/article/pii/S0093641318301216 JO - Mechanics Research Communications ER - TY - JOUR T1 - Strength of wet agglomerates of spherical particles: effects of friction and size distribution JF - EPJ Web of Conferences Y1 - 2017 A1 - Vo, Thanh-Trung A1 - Patrick Mutabaruka A1 - Jean-Yves Delenne A1 - Saeid Nezamabadi A1 - Farhang Radjaï ED - Luding, S. AB -We investigate the mechanical behavior of wet granular agglomerates composed of spherical particles by means of molecular dynamics simulations. The capillary cohesion force is modeled as an attraction force at the contact between two particles and expressed as an explicit function of the gap and volume of the liquid bridge. We are interested in the effect of the friction coefficient between primary particles. The agglomerates are subjected to diametrical compression tests. We find that the deformation is ductile involving particle rearrangements. However, a well-defined stress peak is observed and the peak stress is used as a measure of the compressive strength of the agglomerate. The strength increases with friction coefficient but levels off at friction coefficients above 0.4. Furthermore, the compressive strength is an increasing function of particle size span.

VL - 140 UR - http://www.epj-conferences.org/10.1051/epjconf/201714008021 JO - EPJ Web Conf. ER -