The dynamics of charged Coulomb grains in a plasma is numerically and analytically investigated. Analogous to recent experiments, it is assumed that the grains are trapped in an external parabolic field. Our simulations are based on a Langevin model, where the grain-plasma interaction is realized by a velocity-dependent friction coefficient and a velocity-independent diffusion coefficient. In a...

Mechanical joints, such as the bolted shear lap joint considered here, are ubiquitous in engineered structures, which realize vibration damping as well as load transfer from them. However, the prediction of the energydissipation characteristics of such joints remains a challenging problem. A cubic relationship between energy dissipated and load magnitude is often assumed in classical joint dyna...

Depending on the application, friction in mechanical systems can be a desirable or an undesirable thing. In order to optimally utilize or compensate for the frictional effect in the system, characterization of the frictional behavior is a crucial task. Unfortunately, friction force exhibits strong (hysteretic) nonlinear relationship with sliding velocity, displacement and time, which makes the ...

In this paper, a new approach employing both adaptive and robust methodologies is proposed for stick—slip friction compensation for tracking control of a one degree-of-freedom DC-motor system. It is well known that the major components of friction are Coulomb force, viscous force, exponential force (used to model the downward bend of friction at low velocity) and position-dependent force. Visco...

In this paper the interface behaviour between steel and concrete, during pull out tests, is numerically investigated using an interface model coupling adhesion and friction. This model (RCCM) was developed by Raous, Cangémi, Cocu and Monerie. It is based on the adhesion intensity variable, introduced by Frémond, which is a surface damage variable and its values vary between zero (no adhesion) a...

Large strains, anisotropy of mechanical properties of materials and Coulomb friction in contact regions are some properties in the analysis of deep drawing process. In this research, the effects of different parameters such as anisotropy coefficient, work hardening exponent and friction coefficient on deep drawing process of drawing quality steel are studied. For this purpose, the finite elemen...

For a point mass subject to Coulomb friction in feedback with a PID controller, we consider a model based on a differential inclusion comprising all the possible magnitudes of static friction during the stick phase and having unique solutions. We study the set of all equilibria and we establish its global asymptotic stability using a discontinuous Lyapunovlike function, and a suitable LaSalle’s...

nt matter & 2007 IAgrE. temseng.2007.02.013 thor. Tel.: +1 217 333 2854; : [email protected] (T.E. Gri This paper describes the development of a device capable of measuring the dynamic friction coefficient of particles accelerated in a tube spinning in a horizontal plane. The dynamic friction coefficient is not the classical Coulomb friction coefficient, but a lumped parameter influenced by the Co...

The behavior of marine-terminating ice sheets, such as the West Antarctic ice sheet, is of interest due to the possibility of rapid grounding-line retreat and consequent catastrophic loss of ice. Critical to modeling this behavior is a choice of basal rheology, where the most popular approach is to relate the ice-sheet velocity to a power-law function of basal stress. Recent experiments, howeve...

Anyone who has built a sandcastle recognizes that the addition of liquid to granular materials increases their stability. However, measurements of this increased stability often conflict with theory and with each other [1–7]. A friction-based Mohr-Coulomb model has been developed [3, 8]. However, it distinguishes between granular friction and inter-particle friction, and uses the former without...