نتایج جستجو برای: including friction velocity
تعداد نتایج: 1131257 فیلتر نتایج به سال:
To demonstrate the influence of sliding friction of motion on a curve, a circular path is considered for simplicity on which a person slides from the highest point to the lowest point. A slide which represents a quadrant of radius 5 m and a person of mass 60 kg are considered for comparison in this paper. A Differential equation for motion considering the fact that the normal force depends both...
Isothermal gas flows in microchannels is studied using the lattice Boltzmann method. A novel equation relating Knudsen number with relaxation time is derived. The slipvelocity on the solid boundaries is reasonably realized by combining the bounce-back reflection with specular reflection in a certain proportion. Predicted characteristics in a two-dimensional microchannel flow, including slip-vel...
We present a method for achieving geometrical constraint stabilization for a linear-complementaritybased time-stepping scheme for rigid multibody dynamics with joints, contact, and friction. The method requires the solution of only one linear complementarity problem per step. We prove that the velocity stays bounded and that the constraint infeasibility is uniformly bounded in terms of the size...
This paper examines the effect of friction model on the simulation accuracy of a hydraulic cylinder by using three friction models: a steady-state friction model, the LuGre model, and the new modified LuGre model. Hydraulic cylinder’s behaviors were measured under sinusoidal input to the servo valve. Simulations were conducted under the same conditions as the experiments. The comparisons of sim...
Snow sublimation is an important hydrological process and one of the main causes of the temporal and spatial variation of snow distribution. Compared with surface sublimation, drifting snow sublimation is more effective due to the greater surface exposure area of snow particles in the air. Previous studies of drifting snow sublimation have focused on suspended snow, and few have considered salt...
Acceleration–force setups for multi-rigid-body dynamics are known to be inconsistent for some configurations and sufficiently large friction coefficients (a Painleve paradox). This difficulty is circumvented by time-stepping methods using impulse-velocity approaches, which solve complementarity problems with possibly nonconvex solution sets. We show that very simple configurations involving two...
Alkylsilane monolayer films are used in the fabrication of microelectromechanical systems (MEMS) as anti-stiction coatings. Recently, these films are also being considered as anti-friction coating for MEMS parts that operate under conditions of friction, such as gears, motors, etc. Study of frictional behaviour of these films is of significant interest from the performance point of view. In thi...
The sliding friction force exerted by stochastic linkers interacting with a moving filament is calculated. The elastic properties of the substrate on which the linkers are anchored are shown to strongly influence the friction force. In some cases, the force is maximal for a finite substrate rigidity. Collective effects give rise to a dynamical instability resulting in a stick-slip behaviour, wh...
This paper describes friction compensation based control of an industrial pneumatic actuator used for the variable geometry turbocharger (VGT). Adaptive LuGre model for friction has been used in this work. Friction force that is responsible for hysteresis and hunting phenomenon in the position control is compensated with two different control strategies designed to improve low velocity position...
In analogy with the standard macroscopic friction, here we present a comparative study of the friction force felt by moving vortices in superconductors and charge density waves. Using experiments and a model for this data, our observations (1) provide a link between friction at the micro- and macroscopic scales, (2) explain the roundness of the static-kinetic friction transition in terms of the...
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