A discrete particle model and numerical modeling of the failure modes of granular materials

Abstract

Purpose -To present a discrete particle model for granular materials. Design/methodology/approach -Starting with kinematical analysis of relative movements of two typical circular grains with different radii in contact, both the relative rolling and the relative sliding motion measurements at contact, including translational and angular velocities (displacements) are defined. Both the rolling and sliding friction tangential forces, and the rolling friction resistance moment, which are constitutively related to corresponding relative motion measurements defined, are formulated and integrated into the framework of dynamic model of the discrete element method. Findings -Numerical results demonstrate that the importance of rolling friction resistance, including both rolling friction tangential force and rolling friction resistance moment, in correct simulations of physical behavior in particulate systems; and the capability of the proposed model in simulating the different types of failure modes, such as the landslide (shear bands), the compression cracking and the mud avalanching, in granular materials. Research limitations/implications -Each grain in the particulate system under consideration is assumed to be rigid and circular. Do not account for the effects of plastic deformation at the contact points. Practical implications -To model the failure phenomena of granular materials in geo-mechanics and geo-technical engineering problems; and to be a component model in a combined discrete-continuum macroscopic approach or a two-scale discrete-continuum micro-macro-scopic approach to granular media. Originality/value -This paper develops a new discrete particle model to describe granular media in several branches of engineering such as soil mechanics, power technologies or sintering processes.

A saturated discrete particle model and characteristic‐based SPH method in granular materials

“…There exist many different models, among which are the pioneering work of Cundall and Strack [1] and subsequent significant publications [2][3][4][5][6][7][8][9][10][11][12][13]. The discrete element model used here for solid particles is based on that for dry granular materials presented in [14], which is in turn based on kinematical analysis of relative movements of two typical circular grains with different radii in contact. In the model, both the relative rolling and the relative sliding measurements at contact, including translational and angular velocities (displacements) are defined.…”

“…The DEM [1] is based on modelling of the interaction between individual grains. Significant efforts have been devoted to develop different discrete element models that can describe the normal and tangential contact forces and contact moments in particulate systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. As far as granular media saturated by the interstitial liquid is concerned, modelling of pore fluids interacted with solid particles is required.…”

Micro–macro homogenization of granular materials based on the average-field theory of Cosserat continuum

“…The rates of the contacting force vector _ f pq l applied to a particle p by a neighbor particle q via the contacting point can be expressed as [10,31,32] _ f…”

Anisotropy of microstructure and force chains in granular materials

“…The classical contact models such as Cundall model do not take into account the particle rolling or relative particle rotation. With recognizing the role of particle rolling on the mechanical behavior, various contact models incorporating particle rolling are suggested [5][6]. In this study, the normal and tangential contact forces are computed by the Cundall model, the rolling moment is computed by a model which can be easily implemented on the twodimensional computer code, Particle Flow Code (PFC2d), i.e.…”

“…This approach has been used by researchers. The detailed information can be referred to Mohamed and Gutierrez's work [6]. rolling coefficient, and reaches its peak at about axial strain 2%, then decreases to some extent, and keeps constant with further loading.…”