DEM Simulation of a Schulze Ring Shear Tester

Abstract

The Schulze ring shear tester allows measurement of yield loci for bulk granular solids and of the friction between the solids and the container wall material. These measurements are required inputs in a systematic design method for hoppers. The measurements are subject to test-to-test variations caused by the combined effects of several factors, such as cell filling technique, sampling technique, particle size and shape distribution of the loaded sample and cell size relative to the particle size. One difficulty for the experimenter is to decide which factors are most important in the shear test outcome. In this paper, we validate Discrete Element Model (DEM) simulation parameters with physical measurements of the JSC-1A lunar soil simulant, and inform about the relative impact of the various parameters to the shear test outcome. Specific tests will include sensitivity studies using DEM simulations that probe the effects of particle-to-cell size ratio, particle size distribution, particle shape, shear modulus and inter-particle adhesion and friction on shear failure.

Effects of symmetry energy and momentum dependent interaction on low-energy reaction mechanisms

“…It is known from quantum mechanics that the E1 response of nuclei is [9,13] S whereD is the dipole operator, E 0 is the energy of the ground state |0 , while the energies E n correspond to the excited states |n , eigenstates of the Hamiltonian of the system. The corresponding strength function in the semiclassical framework can be obtained by the Fourier transformation of the perturbation observable…”

“…In refs. [8,9], a microscopic transport model based on the Landau-Vlasov kinetic equation was used to systematically study the correlation between the PDR peak position and the mass number of the nucleus considered, and the correlation between the Energy-Weighted Sum Rule (EWSR) attributed to the PDR mode and the neutron skin thickness. The role of the isovector sector of the nuclear effective interaction was also explored, by considering three different parametrizations of the symmetry energy, but momentum dependent effects were neglected.…”

Computational and Experimental Studies of Flexible Fiber Flows in a Normal‐Stress‐Fixed Shear Cell

“…Preventing particle rotation can also increase the internal friction angle . The effect of particle stiffness was shown to be limited in the high stiffness range while it was more significant in the low stiffness range, and cohesive forces between particles caused an increase in the peak shear stress while it had no effect on the steady‐state stress . The particle Poisson's ratio, coefficient of restitution, and particle‐wall friction coefficient were found to have insignificant effects on shear test outcomes .…”

“…The particle‐particle friction coefficient, which may be difficult to measure (for fine powders in particular), has been calibrated by fitting numerical simulation results to experimental measurements of a shear tester . A sensitivity analysis using DEM simulations of shear tests has shown that particle‐particle friction coefficients (sliding and rolling) dominate shear test outcomes . Particle shape also has a significant effect: larger angles of internal friction were obtained for angular particles and elongated particles with moderate particle aspect ratios in the range from one to two as a result of the interlocking of particles.…”

“…A sensitivity analysis using DEM simulations of shear tests has shown that particle‐particle friction coefficients (sliding and rolling) dominate shear test outcomes . Particle shape also has a significant effect: larger angles of internal friction were obtained for angular particles and elongated particles with moderate particle aspect ratios in the range from one to two as a result of the interlocking of particles. Preventing particle rotation can also increase the internal friction angle .…”