Application Research of Stick-Slip Mechanism on MW Wind Turbine Yaw System

2012 ◽  
Vol 220-223 ◽  
pp. 463-468
Author(s):  
Xiao Guang Li ◽  
Ping Zhao ◽  
Jie Zhong
Keyword(s):  
Wind Turbine ◽  
Damping Ratio ◽  
Kinematic Model ◽  
Torsional Stiffness ◽  
Application Research ◽  
Stick Slip ◽  
Rotating Speed ◽  
Slip Mechanism ◽  
Simulation Calculation ◽  
Stick Slip Motion

The “stick-slip” motion or creep phenomenon is often observed in MW wind turbine yaw system. Yam system stick-slip coupling phenomenon was analyzed, and stick-slip coupling kinematic model was established and simulated by Simulink. The influence of torsional stiffness, friction coefficient difference, rotating speed, damping ratio and tightening torque on system was researched. Main measures for elimination of stick-slip coupling phenomenon were given through theoretical analysis and simulation calculation.

An Experimental and Analytical Investigation Into Friction-Induced Vibrations and Parameters Affecting Its Occurrence

2010 ◽  
Author(s):  
A. Bahzad ◽  
M. O. A. Mokhtar ◽  
A. M. A. El-Butch ◽  
A. F. Fahim
Keyword(s):  
Damping Ratio ◽  
Excitation Frequency ◽  
Analytical Investigation ◽  
Load Factor ◽  
Stick Slip ◽  
Single Degree Of Freedom ◽  
Ratio Speed ◽  
Friction Models ◽  
Stick Slip Motion ◽  
Slip Motion

The condition for the occurrence of friction-induced vibrations is examined numerically and experimentally based on a single degree of freedom system with different friction models that relates the friction force with the relative interface speed. In this study the dimensionless parameters which control the occurrence of stick-slip motion are investigated, it is found that some of these parameters results in the occurrence of stick-slip motion while others are acting to avoid it. The equations governing the occurrence of friction-induced vibrations are derived in dimensionless form and solved numerically in order to have both high accuracy and reducing the number of the system parameters. The attained numerical results are validated by the comparison with the experimental results. Results also showed that damping ratio, speed, load factor, the used friction models and excitation frequency greatly affecting the occurrence of stick-slip motion.

Modeling and Simulation of Stick-Slip Motion for Pneumatic Cylinder Based on Meter-In Circuit

2011 ◽  
Vol 130-134 ◽  
pp. 775-780 ◽  
Author(s):  
Peng Fei Qian ◽  
Guo Liang Tao ◽  
Jian Feng Chen ◽  
Bo Lu
Keyword(s):  
Mathematical Model ◽  
Pneumatic Cylinder ◽  
Practical Application ◽  
Stick Slip ◽  
Slip Mechanism ◽  
Runge Kutta Method ◽  
Variable Step ◽  
Order Variable ◽  
Stick Slip Motion ◽  
Slip Motion

For the stick-slip phenomenon encountered in the pneumatic cylinder motion in practical application, the stick-slip mechanism was analyzed and an nonlinear mathematical model based on the improved LuGre model of pneumatic cylinder movement was established. The movement of the piston and the pressure of the rodless chamber in the pneumatic cylinder based on meter-in circuit were obtained through solving the differential equations by four-order variable-step Runge-Kutta method. The comparison between simulation and experimental results shows that the established mathematical model can describe the stick-slip motion of pneumatic cylinder with a relatively good accuracy.

The Influence of Friction-Speed Relation on the Occurrence of Stick-Slip Motion

1995 ◽  
Vol 117 (3) ◽  
pp. 450-455 ◽  
Author(s):  
Hsien-I You ◽  
Jeng-Hong Hsia
Keyword(s):  
Damping Ratio ◽  
Negative Slope ◽  
Damping Force ◽  
Stick Slip ◽  
Driving Speed ◽  
Speed Parameter ◽  
Nonuniform Motion ◽  
Stick Slip Motion ◽  
Inversion State ◽  
Slip Motion

A theoretical study of stick-slip motion is provided in the present paper. The study focuses on the influence of the friction-speed relation and the effects of driving speed and damping force of the system on the behavior of the stick-slip motion. The two latter effects are characterized by the speed parameter, Sp, and the damping ratio,ξ, respectively. The results show that, for a system undergoing nonuniform motion, the vibratory frequency increases and the amplitude decreases as the speed parameter increases. For two contacting sliding surfaces, there exists an inversion state at which the stick-slip motion disappears. The magnitude of the negative slope of the friction-speed relation near Vr = 0 is shown to have significant effect on the occurrence of the stick-slip motion.

scholarly journals A model of processive walking and slipping of kinesin-8 molecular motors

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ping Xie
Keyword(s):  
Single Molecule ◽  
Molecular Motors ◽  
External Load ◽  
Molecular Motor ◽  
Velocity Versus ◽  
Stick Slip ◽  
Load Dependence ◽  
Chemomechanical Coupling ◽  
Similarities And Differences ◽  
Stick Slip Motion

AbstractKinesin-8 molecular motor can move with superprocessivity on microtubules towards the plus end by hydrolyzing ATP molecules, depolymerizing microtubules. The available single molecule data for yeast kinesin-8 (Kip3) motor showed that its superprocessive movement is frequently interrupted by brief stick–slip motion. Here, a model is presented for the chemomechanical coupling of the kinesin-8 motor. On the basis of the model, the dynamics of Kip3 motor is studied analytically. The analytical results reproduce quantitatively the available single molecule data on velocity without including the slip and that with including the slip versus external load at saturating ATP as well as slipping velocity versus external load at saturating ADP and no ATP. Predicted results on load dependence of stepping ratio at saturating ATP and load dependence of velocity at non-saturating ATP are provided. Similarities and differences between dynamics of kinesin-8 and that of kinesin-1 are discussed.

Dynamics of stick–slip motion, Whillans Ice Stream, Antarctica

2011 ◽  
Vol 305 (3-4) ◽  
pp. 283-289 ◽  
Author(s):  
J. Paul Winberry ◽  
Sridhar Anandakrishnan ◽  
Douglas A. Wiens ◽  
Richard B. Alley ◽  
Knut Christianson
Keyword(s):  
Stick Slip ◽  
Ice Stream ◽  
Whillans Ice Stream ◽  
Stick Slip Motion ◽  
Slip Motion

GRANULAR FAILURE: THE ORIGIN OF EARTHQUAKES?

2009 ◽  
Vol 23 (28n29) ◽  
pp. 5374-5382 ◽  
Author(s):  
MASSIMO PICA CIAMARRA ◽  
LUCILLA DE ARCANGELIS ◽  
EUGENIO LIPPIELLO ◽  
CATALDO GODANO
Keyword(s):  
Confining Pressure ◽  
Stick Slip ◽  
Slip Regime ◽  
Constant Rate ◽  
Large Fluctuations ◽  
System Flow ◽  
System Phase Diagram ◽  
Dynamics Simulations ◽  
Stick Slip Motion ◽  
System Phase

Via Molecular Dynamics simulations, we investigate the stick-slip motion in a model of fault, where two surfaces subject to a constant confining pressure P, and enclosing granular particles, are subject a shear stress σ. When the system sticks, the stress increases with a constant rate [Formula: see text], while the stress decreases when the system flow. We dermine the system 'phase diagram' in the pressure P load velocity [Formula: see text] plane, locating the transition form the continuos flow regime to the stick-slip regimes, and show that the transition between these two regimes is characterized by the presence of large fluctuations. In the stick-slip regime, the system reproduces the behaviour of a segment of a fault of fixed lenght.

Dynamic simulation of stick–slip motion of a flexible solar array

2008 ◽  
Vol 16 (6) ◽  
pp. 724-735 ◽  
Author(s):  
Yasushi Kojima ◽  
Shigemune Taniwaki ◽  
Yoshiaki Okami
Keyword(s):  
Dynamic Simulation ◽  
Solar Array ◽  
Stick Slip ◽  
Stick Slip Motion ◽  
Slip Motion

Mean Wave Drift Force on a Barge-Type Floating Wind Turbine With Moonpools

2021 ◽  
Author(s):  
Lei Tan ◽  
Tomoki Ikoma ◽  
Yasuhiro Aida ◽  
Koichi Masuda
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Hydrodynamic Performance ◽  
Vertical Axis Wind Turbine ◽  
Rotating Speed ◽  
Wave Drift ◽  
Floating Offshore Wind Turbines ◽  
Drift Force ◽  
Gyroscopic Effects

Abstract The barge-type foundation with moonpool(s) is a promising type of platform for floating offshore wind turbines, since the moonpool(s) could improve the hydrodynamic performance at particular frequencies and reduce the costs of construction. In this paper, the horizontal mean drift force and yaw drift moment of a barge-type platform with four moonpools are numerically and experimentally investigated. Physical model tests are carried out in a wave tank, where a 2MW vertical-axis wind turbine is modelled in the 1:100 scale. By varying the rotating speed of the turbine and the mass of the blades, the gyroscopic effects due to turbine rotations on the mean drift forces are experimentally examined. The wave diffraction and radiation code WAMIT is used to carry out numerical analysis of wave drift force and moment. The experimental results indicate that the influence of the rotations of a vertical-axis wind turbine on the sway drift force is generally not very significant. The predictions by WAMIT are in reasonable agreement with the measured data. Numerical results demonstrate that the horizontal mean drift force and yaw drift moment at certain frequencies could be reduced by moonpool(s).

Analysis of Beam-Like Structures With Displacement-Dependent Friction Forces: Part I — Single-Degree-of-Freedom Model

1995 ◽  
Author(s):  
Wayne E. Whiteman ◽  
Aldo A. Ferri
Keyword(s):  
Dry Friction ◽  
Damping Ratio ◽  
Strong Dependence ◽  
Time Integration ◽  
Single Mode ◽  
Stick Slip ◽  
Friction Forces ◽  
Equivalent Damping ◽  
Damping Characteristics ◽  
Parameter Values

Abstract The dynamic behavior of a beam-like structure undergoing transverse vibration and subjected to a displacement-dependent dry friction force is examined. In Part I, the beam is modeled by a single mode while Part II considers multi-mode representations. The displacement dependence in each case is caused by a ramp configuration that allows the normal force across the sliding interface to increase linearly with slip displacement. The system is studied first by using first-order harmonic balance and then by using a time integration method. The stick-slip behavior of the system is also studied. Even though the only source of damping is dry friction, the system is seen to exhibit “viscous-like” damping characteristics. A strong dependence of the equivalent natural frequency and damping ratio on the displacement amplitude is an interesting result. It is shown that for a given set of parameter values, an optimal ramp angle exists that maximizes the equivalent damping ratio. The appearance of two dynamic response solutions at certain system and forcing parameter values is also seen. Results suggest that the overall characteristics of mechanical systems may be improved by properly configuring frictional interfaces to allow normal forces to vary with displacement.

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