In this paper, a SDOF system with nonlinear viscous friction under harmonic excitation is studied. A nonlinear viscous friction model is built as an exponential expansion of the relative slip velocity. According to the adaptive control theory, an adaptive controller for the friction compensation of the SDOF system with nonlinear viscous friction is put forward by using the model-based parameter...

[1] The slip behavior of major faults depends largely on the frictional and hydrologic properties of fault gouge. We report on laboratory experiments designed to measure the strength, friction constitutive properties, and permeability of a suite of saturated clay-rich fault gouges, including: a 50:50% mixture of montmorillonite-quartz, powdered illite shale, and powdered chlorite schist. Fricti...

Received (received date) Revised (revised date) We investigate a new method for simulating polymer-solvent systems which combines a lattice Boltzmann approach for the uid with a continuum molecular dynamics (MD) model for the polymer chain. The two parts are coupled by a friction force which is proportional to the diierence of the monomer velocity and the uid velocity at the monomer's position....

Nonlinear observers for estimation of lateral and longitudinal velocity of automotive vehicles are proposed. The observers are based on a sensor suite that is standard in many new cars, consisting of acceleration and yaw rate measurements in addition to wheel speed and steering angle measurements. Two approaches are considered: first, a modular approach where the estimated longitudinal velocity...

friction welding is widely used in various industries. in friction welding, heat is generated by conversion of mechanical energy into thermal energy at the interface the work pieces during pin rotation under pressure. a three-dimensional thermo mechanical simulation of friction stir welding (fsw) processes is carried out for aluminium alloys of 6061and 7050 where the simulation results are comp...

The present paper reports the laminar fluid flow and heat transfer of a heated array of circular-perforated and solid fins mounted over a flat surface using the finite-volume method. One to four circular cross-sectional perforations are made along the length of the fins. The SIMPLE algorithm is used for pressure-velocity coupling and the second order upwind technique is employed to discreti...

An analytical investigation is conducted to study the unsteady free convection heat and mass transfer flow through a non-homogeneous porous medium with variable permeability bounded by an infinite porous vertical plate in slip flow regime while taking into account the thermal radiation, chemical reaction, the Soret number, and temperature gradient dependent heat source. The flow is considered u...

In the present paper, discrete element method (DEM) is used to study wave propagation phenomenon in granular soils. The effect of factors such as coefficient of friction, frequency, normal stiffness and soil gradation on the wave velocity is studied. Using the wall motion based on the sinusoidal function is the method of loading used in this simulation, through which the pressure wave is transf...

An analysis is suggested to study the impact of Hall currents in Jeffrey fluid which is chemically reactive through a porous medium limited by a semi-infinite vertical permeable plate within the existence of heat generation. An evenly distributed magnetic field turns vertically on the porous surface which absorbs the Jeffrey fluid with a changed suction velocity with time. The analytical expres...

Abstract: Development of velocity observers for mechanical systems with friction deserves a special emphasis, because as evidenced in numerical and experimental tests when a state-of-the-art observer is armed, friction can induce high-frequency oscillations in the estimated signal. In this short paper, two new velocity-observation algorithms are designed, based on this previously reported obser...