AbstracL We present an implemenlalion of realistic static friction in molecular dynamics (MD) simulations of granular particles. In our model, to break contact between two particles, one has to apply a Bnile amount of force, determined by the Coulomb criterion. Using a Wo.dimmsional model, we show that piles generated by avalanches have a @e angle of repose 8, (finite slopes). Furthermore, thes...

We present experimental measurements of a granular slope under horizontal vibration. We use optical particle tracking to measure the motion of surface beads as the slope fails. We find that for all but the largest inclination angles, initial bead motion leads to strengthening rather than an avalanche. The initial motion of the beads is usually intermittent and evolves differently for different ...

A decrease in current with increasing voltage, often referred to as negative differential resistance NDR , has been observed in many electronic devices and can usually be understood within a one-electron picture. However, NDR has recently been reported in nanoscale devices with large single-electron charging energies which require a many-electron picture in Fock space. This paper presents a gen...

a new dynamic friction model for modeling of elliptical vibration assisted turning (evat) was developed in this research. the periodic change of the friction force direction is known to be one of the most important causes of this phenomenon. in modeling of machining processes (including the evat process), static coulomb friction model was employed by most of the researchers. because of the peri...

Abstract Given the complexities of reservoir exploration and development, it is vital to understand geomechanical properties well in drilling operation. In constructing a mechanical model earth, combination environmental parameters, as magnitude direction stresses, used. this study, stress analysis its effect on azimuth deviated an oil field located southwestern Iran are investigated. Necessary...

Dynamic compaction is a soil improvement method which has been widely used for the increase of bearing capacity through stress wave propagation during heavy tamping. The cost and time of project implementation can be effectively curtailed by developing a model that can be used in the design of dynamic compaction operations. The numerical models offered so far are mostly one or two-dimensional, ...

In the current paper the results of a numerical simulation that were verified by a well instrumented experimental procedure for studying the arching effect over a trapdoor in sand is presented. To simulate this phenomenon with continuum mechanics, the experimental procedure is modeled in ABAQUS code using stress dependent hardening in elastic state and plastic strain dependent frictional harden...

ABSTRACT: In this paper, shakedown limits of non-homogeneous soils in a half-space under rolling and sliding surface loads are investigated. The inhomogeneity of the soil is described by a power law for the variation of Young’s modulus with the depth. Mohr-Coulomb criterion is employed to characterise the cohesive-frictional behaviour of the soil. Analytical solutions to the elastic stress fiel...

We systematically investigate the incremental response of various equilibrium states of dense 2D model granular materials, along the biaxial compression path (σ11 < σ22, σ12 = 0). Stress increments are applied in arbitrary directions in 3dimensional stress space (σ11,σ22,σ12). In states with stable contact networks we compute the stiffness matrix and the elastic moduli, and separate elastic and...