112 citations · 669 across the 19 of their papers we have counts for
19 papers
Deformation Measures for Granular Materials
Matthew R. Kuhn
The paper presents a micromechanical representation of deformation in 2D granular materials. The representation is a generalization of K. Bagi's work and is based upon the void-cel…
Linear-frictional contact model for 3D discrete element simulations of granular systems
Matthew R. Kuhn, Kiichi Suzuki, Ali Daouadji
The linear-frictional contact model is the most commonly used contact mechanism for discrete element (DEM) simulations of granular materials. Linear springs with a frictional slide…
Heterogeneity and patterning in the quasi-static behavior of granular materials
Matthew R. Kuhn
Heterogeneity is classified in five categories---topologic, geometric, kinematic, static, and constitutive---and the first four categories are investigated in a numerical DEM simul…
Contact rolling and deformation in granular media
Matthew R. Kuhn, Katalin Bagi
The paper considers rotations at different scales in granular materials: the rotations of individual particles, the rolling and rigid-rotation of particle pairs, the rotational int…
Micro-mechanics of fabric and failure in granular materials
Matthew R. Kuhn
The paper addresses the underlying source of two forms of induced anisotropy in granular materials: contact orientation anisotropy and contact force anisotropy. A rational, mathema…
Stability, bifurcation, and softening in discrete systems: A conceptual approach for granular materials
Matthew R. Kuhn, Ching S. Chang
Matrix stiffness expressions are derived for the particle movements in an assembly of rigid granules having compliant contacts. The derivations include stiffness terms that arise f…
Are granular materials simple? An experimental study of strain gradient effects and localization
Matthew R. Kuhn
Experiments test the dependence of shearing stress on the first two gradients of shear strain. The tests were conducted by direct numerical simulation using the Discrete Element Me…
Transient rolling friction model for discrete element simulations of sphere assemblies
Matthew R. Kuhn
The rolling resistance between a pair of contacting particles can be modeled with two mechanisms. The first mechanism, already widely addressed in the DEM literature, involves a co…
Investigation of cyclic liquefaction with discrete element simulations
Matthew R. Kuhn, Hannah E. Renken, Austin D. Mixsell +1
A discrete-element method (DEM) assembly of virtual particles is calibrated to approximate the behavior of a natural sand in undrained loading. The particles are octahedral, bumpy…
Implementation of the Jager contact model for discrete element simulations
Matthew R. Kuhn
In three-dimensional discrete element method (DEM) simulations, the particle motions within a granular assembly can produce bewildering sequences of movements at the contacts betwe…
Dense granular flow at the critical state: maximum entropy and topological disorder
Matthew R. Kuhn
After extensive quasi-static shearing, dense dry granular flows attain a steady-state condition of porosity and deviatoric stress, even as particles are continually rearranged. The…
Stress-induced anisotropy in granular materials: fabric, stiffness, and permeability
Matthew R. Kuhn, WaiChing Sun, Qi Wang
The loading of a granular material induces anisotropies of the particle arrangement (fabric) and of the material's strength, incremental stiffness, and permeability. Thirteen measu…
Maximum disorder model for dense steady-state flow of granular materials
Matthew R. Kuhn
A flow model is developed for dense shear-driven granular flow. As described in the geomechanics literature, a critical state condition is reached after sufficient shearing beyond…
Contact transience during slow loading of dense granular materials
Matthew R. Kuhn
The irregularity of particle motions during quasi-static deformation is investigated using discrete element (DEM) simulations of sphere and sphere-cluster assemblies. A total of th…
The critical state of granular media: Convergence, stationarity, and disorder
Matthew R. Kuhn
Discrete-element simulations are used to monitor several micro-scale characteristics within a granular material, demonstrating their convergence during loading toward the critical…
Stiffness pathologies in discrete granular systems: bifurcation, neutral equilibrium, and instability in the presence of kinematic constraints
Matthew R. Kuhn, Florent Prunier, Ali Daouadji
The paper develops the stiffness relationship between the movements and forces among a system of discrete interacting grains. The approach is similar to that used in structural ana…
Measurement of higher-order stress-strain effects in granular materials undergoing non-uniform deformation
Matthew R. Kuhn, Ching S. Chang
Discrete element (DEM) simulations demonstrate that granular materials are non-simple, meaning that the incremental stiffness of a granular assembly depends on the gradients of the…
Multi-directional behavior of granular materials and its relation to incremental elasto-plasticity
Matthew R. Kuhn, Ali Daouadji
The complex incremental behavior of granular materials is explored with multi-directional loading probes. An advanced discrete element model (DEM) was used to examine the reversibl…
Quasi-static incremental behavior of granular materials: elastic-plastic coupling and micro-scale dissipation
Matthew R. Kuhn, Ali Daouadji
The paper addresses a common assumption of elastoplastic modeling: that the recoverable, elastic strain increment is unaffected by alterations of the elastic moduli that accompany…