Review and comparison of dry friction force models

2015 ◽  
Vol 83 (4) ◽  
pp. 1785-1801 ◽  
Author(s):  
Ettore Pennestrì ◽  
Valerio Rossi ◽  
Pietro Salvini ◽  
Pier Paolo Valentini
Keyword(s):  
Friction Force ◽  
Dry Friction

Tribology research of the turned zirconium-dioxide ceramics

2012 ◽  
Vol 3 (3) ◽  
pp. 181-190
Author(s):  
G. Fledrich ◽  
R. Keresztes ◽  
L. Zsidai
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Dry Friction ◽  
Zirconium Dioxide ◽  
Steel Specimen ◽  
Friction Condition ◽  
Normal Direction ◽  
Basic Material ◽  
Series Production ◽  
Ceramic Specimen

The zirconium dioxide as basic material is suitable to machine by tool with regular edge derivingfrom lower ceramic hardness and from other characteristics so in case of piece production or small – andmedium series production, at quick prototype production can become potential material alike. The aims tocompare the arising frictional characteristics in case of dry friction condition in case of ceramic – steelsurface pairs machined with different sets. We have developed for an equipment to carry out tribologicaltests. During the test we pressure the steel counter face with determined normal direction force thecasing surface of the rotating ceramic specimen and in the meantime we measure the value of the frictionforce with force meter cell. We have calculated the friction coefficient characterizing the system from thenormal direction force and the friction force as well as we measured the wear of the steel specimen andits deformation.

Forced Response Prediction of Blades With Loosely Assembled Dovetail Attachment by HBM

2009 ◽  
Author(s):  
Shangguan Bo ◽  
Zili Xu ◽  
Qilin Wu ◽  
XianDing Zhou ◽  
ShouHong Cao
Keyword(s):  
Friction Force ◽  
Centrifugal Force ◽  
Dry Friction ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Forced Response ◽  
Balance Method ◽  
Force Model ◽  
Equivalent Stiffness ◽  
Equivalent Damping

To understand the mechanism of interfacial damping of axial loosely assembled dovetail to suppress blade vibration, a dry friction force model is presented by the Coulomb friction law and the macroslip model, and the mathematical expression of the friction force is derived. The nonlinear friction force is linearized as an equivalent stiffness and an equivalent damping through the one-term harmonic balance method. The effect of centrifugal force on the equivalent stiffness and the equivalent damping is studied. The forced response of one simplified blade with loosely assembled dovetail attachment is predicted by the harmonic balance method, in which the blade is described by the lumped mass and spring model, and the friction contact joints is simplified as a ideal friction damper. The results show that the equivalent stiffness of loosely assembled dovetail attachment increases with blade centrifugal force, gradually reaches a certain value, and there exists the maximum value for the equivalent stiffness. The equivalent damping increases at the beginning and then decreases with blade centrifugal force increasing, there exists a maximum too. The resonant frequency of blade rises with blade centrifugal force, but it no longer increases when the centrifugal force exceed a certain value. There exists a special centrifugal force on which the effect of dry friction damping is the best.

Dry Friction Effect on the Work of Viscous Torsion Damper

2016 ◽  
Vol 817 ◽  
pp. 13-18
Author(s):  
Celina Jagiełowicz-Ryznar
Keyword(s):  
Friction Coefficient ◽  
Free Vibration ◽  
Friction Force ◽  
Vibration Frequency ◽  
Forced Vibration ◽  
Dry Friction ◽  
Viscous Damper ◽  
The Real ◽  
Free Vibration Frequency ◽  
Marine Engines

The results of crankshaft forced vibration calculations, including the dry friction force which can be formed in the viscous damper bearing sliding, were presented. This problem concerns the big dampers used in the marine engines. The friction force influence is presented using the function {sign}. Low values of friction coefficient, corresponding to the conditions similar to the real ones, were assumed. In the range of tested value, it was found that the vibration increases linearly, and system free vibration frequency doesn’t change practically.

scholarly journals Influence of Dry Friction on the Dynamics of Cantilevered Pipes Conveying Fluid

2022 ◽  
Vol 12 (2) ◽  
pp. 724
Author(s):  
Zilong Guo ◽  
Qiao Ni ◽  
Lin Wang ◽  
Kun Zhou ◽  
Xiangkai Meng
Keyword(s):  
Flow Velocity ◽  
Friction Force ◽  
Dry Friction ◽  
Critical Flow Velocity ◽  
Pipe System ◽  
Pipes Conveying Fluid ◽  
Cantilevered Pipe ◽  
The Stability ◽  
Friction Parameters ◽  
Conveying Fluid

A cantilevered pipe conveying fluid can lose stability via flutter when the flow velocity becomes sufficiently high. In this paper, a dry friction restraint is introduced for the first time, to evaluate the possibility of improving the stability of cantilevered pipes conveying fluid. First, a dynamical model of the cantilevered pipe system with dry friction is established based on the generalized Hamilton’s principle. Then the Galerkin method is utilized to discretize the model of the pipe and to obtain the nonlinear dynamic responses of the pipe. Finally, by changing the values of the friction force and the installation position of the dry friction restraint, the effect of dry friction parameters on the flutter instability of the pipe is evaluated. The results show that the critical flow velocity of the pipe increases with the increment of the friction force. Installing a dry friction restraint near the middle of the pipe can significantly improve the stability of the pipe system. The vibration of the pipe can also be suppressed to some extent by setting reasonable dry friction parameters.

Determination of Contact Area During Small-Scale Friction Experiments by Means of Continuous Stiffness Measurements

2005 ◽  
Author(s):  
Andrei Rar ◽  
Yehuda Y. Braiman ◽  
Warren C. Oliver ◽  
David L. Goldsby ◽  
Terry E. Tullis ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Friction Force ◽  
Direct Measurement ◽  
Contact Area ◽  
Dry Friction ◽  
Contact Stiffness ◽  
Small Scale ◽  
New Approach ◽  
Active Research

Despite the hallmark observation of the almost linear relationship between friction force and contact area in the case of “dry” friction, the direct measurement of this dependency is an area of active research [1, 2]. In this study, a new approach to the measurement of contact area during friction experiments is proposed. The method is based on the well known proportionality between the contact area and the contact stiffness raised to the second power [3]. The main benefit of the proposed method is its broad applicability. Preliminary measurements of the dependence between friction and contact area are discussed.

A Novel Generic Model at Asperity Level for Dry Friction Force Dynamics

2004 ◽  
Vol 16 (1/2) ◽  
pp. 81-93 ◽  
Author(s):  
F. Al-Bender ◽  
V. Lampaert ◽  
J. Swevers
Keyword(s):  
Friction Force ◽  
Dry Friction ◽  
Generic Model ◽  
Force Dynamics

Prediction of Dry-Friction Whirl and Whip Between a Rotor and a Stator

2007 ◽  
Vol 129 (3) ◽  
pp. 355-362 ◽  
Author(s):  
Dara W. Childs ◽  
Avijit Bhattacharya
Keyword(s):  
Friction Force ◽  
Dry Friction ◽  
Coulomb Friction ◽  
Coulomb Force ◽  
Test Results ◽  
Jeffcott Rotor ◽  
Transient Simulations ◽  
Force Direction ◽  
Function Definition ◽  
Coulomb Friction Force

This paper addresses recent test results for dry-friction whip and whirl. Authors of these publications suggest that predictions from Black’s 1968 paper (J. Mech. Eng. Sci., 10(1), pp. 1–12) are deficient in predicting their observed transition speeds from whirl to whip and the associated precession frequencies of whirl and whip motion. Predictions from Black’s simple Jeffcott-rotor/point-mass stator are cited. This model is extended here to a multimode rotor and stator model with an arbitrary axial location for rotor-stator rubbing. Predictions obtained from this new model are quite close to experimental observations in terms of the transition from whip to whirl and observed precession frequencies. Paradoxically, nonlinear numerical simulations using Black’s model fail to produce the whirl and whip solutions. The Coulomb friction force in Black’s model has a fixed direction, and Bartha showed in 2000 (“Dry Friction Backward Whirl of Rotors,” Dissertation, THE No. 13817, ETH Zurich) that by making the friction-force direction depend on the relative sliding velocity, nonlinear simulations would produce the predicted whirl solutions. He also showed that Black’s proposed whip solution at the upper precession-frequency transition from whirl to whip was unstable. The multimode extension of Black’s model predicts a complicated range of whirl and whip possibilities; however, nonlinear time-transient simulations (including the sgn function definition for the Coulomb force) only produce the initial whirl precession range, initial whirl-whip transition, and initial whip frequency. Simulation results for these values agree well with predictions. However, none of the predicted higher-frequency whirl results are obtained. Also, the initial whip frequency persists to quite high running speeds and does not (as predicted) transition to higher frequencies. Hence, despite its deficiencies, correct and very useful predictions are obtained from a reasonable extension of Black’s model.

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