scholarly journals Stick-slip instabilities in sheared granular flow: The role of friction and acoustic vibrations

2015 ◽  
Vol 92 (2) ◽  
Author(s):  
Charles K. C. Lieou ◽  
Ahmed E. Elbanna ◽  
J. S. Langer ◽  
J. M. Carlson
Keyword(s):  
Granular Flow ◽  
Acoustic Vibrations ◽  
Stick Slip

scholarly journals Triggering avalanches by transverse perturbations in a rotating drum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vicente Salinas ◽  
Cristóbal Quiñinao ◽  
Sebastián González ◽  
Gustavo Castillo
Keyword(s):  
Hopf Bifurcation ◽  
Theoretical Model ◽  
Order Parameter ◽  
Small Scale ◽  
Rotating Drum ◽  
Governing Parameter ◽  
Stick Slip ◽  
Slip Regime ◽  
Axis Of Rotation

AbstractWe study the role of small-scale perturbations in the onset of avalanches in a rotating drum in the stick-slip regime. By vibrating the system along the axis of rotation with an amplitude orders of magnitude smaller than the particles’ diameter, we found that the order parameter that properly describes the system is the kinetic energy. We also show that, for high enough frequencies, the onset of the avalanche is determined by the amplitude of the oscillation, contrary to previous studies that showed that either acceleration or velocity was the governing parameter. Finally, we present a theoretical model that explains the transition between the continuous and discrete avalanche regimes as a supercritical Hopf bifurcation.

Dynamic Behaviour of Plain Slideways

1966 ◽  
Vol 181 (1) ◽  
pp. 169-184 ◽  
Author(s):  
R. Bell ◽  
M. Burdekin
Keyword(s):  
Machine Tool ◽  
Dynamic Behaviour ◽  
Damping Capacity ◽  
Friction Characteristic ◽  
Stick Slip ◽  
Friction Characteristics ◽  
Physical Systems ◽  
Major Emphasis

The friction characteristics resulting from the motion of one surface over another form a very important facet of the behaviour of many physical systems. This statement is particularly valid when considering the behaviour of machine tool slideways. Most slideway elements consist of two plain surfaces whose friction characteristic is modified by the addition of a lubricant. In many cases the complete slideway consists of many mating surfaces and the choice of slideway material, slideway machining and lubricant is often influenced by the long term problem of wear. The aim of this paper is to present results of experiments on a test rig designed to be representative of machine tool slideway conditions; the experiments were wholly concerned with the behaviour of the bearing under dynamic conditions. The major emphasis is on results obtained with a polar additive lubricant which appears to exclude the possibility of ‘stick-slip’ oscillations. A parallel series of tests are reported where a normal hydraulic oil was used as lubricant. The use of this second lubricant allowed some study of the ‘stick-slip’ process. The dynamic friction characteristics, cyclic friction characteristics and damping capacity of several slideway surface combinations have been obtained and are discussed in the context of earlier work in the field and the role of slideways in machine tool behaviour.

Response of Materials During Sliding on Various Surface Textures

2007 ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas
Keyword(s):  
Surface Texture ◽  
Soft Materials ◽  
Steel Plates ◽  
Mg Alloy ◽  
Hard Material ◽  
Stick Slip ◽  
The Coefficient Of Friction ◽  
Basic Studies ◽  
Stick Slip Motion

In the present investigation, basic studies were conducted using Inclined pin-on-plate sliding Tester to understand the role of surface texture of hard material against soft materials during sliding. Soft materials such as Al-Mg alloy, pure Al and pure Mg were used as pins and 080 M40 steel was used as plate in the tests. Two surface parameters of steel plates — roughness and texture — were varied in tests. It was observed that the transfer layer formation and the coefficient of friction which has two components, namely adhesion and plowing component, are controlled by the surface texture of harder material. For the case of Al-Mg alloy, stick-slip phenomenon was absent under both dry and lubricated conditions. However, for the case of Al, it was observed only under lubricated conditions while for the case of Mg, it was observed under both dry and lubricated conditions. Further, it was observed that the amplitude of stick-slip motion primarily depends on plowing component of friction. The plowing component of friction was highest for the surface that promotes plane strain conditions near the surface and was lowest for the surface that promotes plane stress conditions near the surface.

A Numerical Study of Non-Symmetric Joints

2007 ◽  
Author(s):  
Edward Berger
Keyword(s):  
Dynamic Systems ◽  
Frequency Tuning ◽  
Numerical Study ◽  
Relative Displacement ◽  
Stick Slip ◽  
Small Perturbations ◽  
Important Indicator ◽  
Frequency Domains ◽  
Displacement Profile

A great deal of analytical, numerical, and experimental research has focused on characterizing symmetric lap-type joints, in which the joint connects dynamic systems with nominally the same descriptions. In this paper, we numerically examine dynamically non-symmetric jointed structures. Starting with the analytical treatments of Pratt and Williams (1981) as verification of our simulation model and approach, we then introduce structural stiffness asymmetries ranging from small perturbations to large differences. The results are presented in both the time and frequency domains, and the role of the dynamic asymmetry is critically examined. The results of this numerical study suggest that both the relative displacement profile and the stick-slip behavior at the joint are sensitive to the dynamics of the two substructures, with frequency tuning of the substructures being an important indicator of joint performance.

scholarly journals Continuum Modeling of Granular Media

2014 ◽  
Vol 66 (5) ◽  
Author(s):  
J. D. Goddard
Keyword(s):  
Granular Flow ◽  
Granular Media ◽  
Evolution Equations ◽  
Particle Migration ◽  
Internal Variables ◽  
Continuum Modeling ◽  
Material Instability ◽  
Rapid Flow ◽  
Internal Balance

This is a survey of the interesting phenomenology and the prominent regimes of granular flow, followed by a unified mathematical synthesis of continuum modeling. The unification is achieved by means of “parametric” viscoelasticity and hypoplasticity based on elastic and inelastic potentials. Fully nonlinear, anisotropic viscoelastoplastic models are achieved by expressing potentials as functions of the joint isotropic invariants of kinematic and structural tensors. These take on the role of evolutionary parameters or “internal variables,” whose evolution equations are derived from the internal balance of generalized forces. The resulting continuum models encompass most of the mechanical constitutive equations currently employed for granular media. Moreover, these models are readily modified to include Cosserat and other multipolar effects. Several outstanding questions are identified as to the contribution of parameter evolution to dissipation; the distinction between quasielastic and inelastic models of material instability; and the role of multipolar effects in material instability, dense rapid flow, and particle migration phenomena.

Studies on Friction and Formation of Transfer Layer in HCP Metals

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas ◽  
Michael R. Lovell
Keyword(s):  
Surface Texture ◽  
Steel Plates ◽  
Ambient Conditions ◽  
Transfer Layer ◽  
Stick Slip ◽  
The Coefficient Of Friction ◽  
Hcp Materials ◽  
Stick Slip Motion ◽  
Slip Motion

Surface texture plays an important role in the frictional behavior and transfer layer formation of contacting surfaces. In the present investigation, basic experiments were conducted using an inclined pin-on-plate sliding apparatus to better understand the role of surface texture on the coefficient of friction and the formation of a transfer layer. In the experiments, soft HCP materials such as pure Mg and pure Zn were used for the pins and a hardened 080 M40 steel was used for the plate. Two surface parameters of the steel plates—roughness and texture—were varied in tests that were conducted at a sliding speed of 2 mm/s in ambient conditions under both dry and lubricated conditions. The morphologies of the worn surfaces of the pins and the formation of the transfer layer on the counter surfaces were observed using a scanning electron microscope. In the experiments, the occurrence of stick-slip motion, the formation of a transfer layer, and the value of friction were recorded. With respect to the friction, both adhesion and plowing components were analyzed. Based on the experimental results, the effect of surface texture on the friction was attributed to differences in the amount of plowing. Both the plowing component of friction and the amplitude of stick-slip motion were determined to increase surface textures that promote plane strain conditions and decrease the textures that favor plane stress conditions.

Numerical simulations of dense granular flow in a two-dimensional channel: The role of exit position

2018 ◽  
Vol 27 (12) ◽  
pp. 124704
Author(s):  
Tingwei Wang ◽  
Xin Li ◽  
Qianqian Wu ◽  
Tengfei Jiao ◽  
Xingyi Liu ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Granular Flow ◽  
Two Dimensional ◽  
Dense Granular Flow

Chaos and Force Fluctuations in Frictional Dynamics

1996 ◽  
Vol 464 ◽  
Author(s):  
M. G. Rozman ◽  
J. Klafter ◽  
M. Urbakh
Keyword(s):  
Chaotic Behavior ◽  
Power Spectra ◽  
Stick Slip ◽  
Liapunov Exponents ◽  
Force Fluctuations ◽  
Periodic Potentials ◽  
Wide Range ◽  
Stick Slip Motion ◽  
Slip Motion

ABSTRACTA model is presented of a particle that interacts with two periodic potentials, representing two confining plates, one of which is externally driven. The model leads to various behaviors in the motion of the top driven plate: stick-slip, intermittent regime, characterized by force fluctuations, and two types of sliding above a critical driving velocity vc. Similar behaviors are typical of a broad range of systems including thin sheared liquids. A detailed analysis of the different regimes displays a transition between the stick-slip and the kinetic regimes, ω−2 power spectra of the force over a wide range of velocities below vc, and a decrease of the force fluctuations that follows (vc – v)½ for v < vc. The velocity dependent Liapunov exponents demonstrate that the stick-slip motion is characterized by a chaotic behavior of the top plate and the embedded particle. An extension of the model to an embedded chain is introduced and preliminary results are presented and confronted with the single particle case. The role of the internal excitations of the chain in frictional dynamics is discussed.

Sign in / Sign up

Export Citation Format

Share Document