scholarly journals Frictional force on sliding drops

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Joel Koplik
Keyword(s):  
Frictional Force

Inducing Frictional Force to Enhance the Transient Response in Beams

2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai
Keyword(s):  
Numerical Analysis ◽  
Transient Response ◽  
Frictional Force ◽  
Damping Ratio ◽  
Experimental Results ◽  
Damping Capacity ◽  
Tightening Force ◽  
Contact Areas ◽  
Good Agreement ◽  
Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

Peristaltic flow of a Jeffery fluid over a porous conduit in the presence of variable liquid properties and convective boundary conditions

2019 ◽  
Vol 6 (2) ◽  
Author(s):  
G. Manjunatha ◽  
C. Rajashekhar ◽  
K. V. Prasad ◽  
Hanumesh Vaidya ◽  
Saraswati
Keyword(s):  
Boundary Conditions ◽  
Frictional Force ◽  
Variable Viscosity ◽  
Pressure Rise ◽  
Velocity Slip ◽  
Peristaltic Flow ◽  
Physical Parameters ◽  
Convective Boundary Conditions ◽  
Convective Boundary ◽  
Closed Form Solutions

The present article addresses the peristaltic flow of a Jeffery fluid over an inclined axisymmetric porous tube with varying viscosity and thermal conductivity. Velocity slip and convective boundary conditions are considered. Resulting governing equations are solved using long wavelength and small Reynolds number approximations. The closed-form solutions are obtained for velocity, streamline, pressure gradient, temperature, pressure rise, and frictional force. The MATLAB numerical simulations are utilized to compute pressure rise and frictional force. The impacts of various physical parameters in the interims for time-averaged flow rate with pressure rise and is examined. The consequences of sinusoidal, multi-sinusoidal, triangular, trapezoidal, and square waveforms on physiological parameters are analyzed and discussed through graphs. The analysis reveals that the presence of variable viscosity helps in controlling the pumping performance of the fluid.

Experimental study on the factors affecting squeak noise occurrence in automotive suspension bushings

2021 ◽  
pp. 095440702110241
Author(s):  
Byunghyun Kang ◽  
Cheol Choi ◽  
Daeun Sung ◽  
Seongho Yoon ◽  
Byoung-Ho Choi
Keyword(s):  
Neural Network ◽  
Logistic Regression ◽  
Influencing Factors ◽  
Frictional Force ◽  
Prediction Models ◽  
Statistical Tests ◽  
Network Models ◽  
Multiple Logistic Regression ◽  
Neural Network Models ◽  
Automotive Suspension

In this study, friction tests are performed, via a custom-built friction tester, on specimens of natural rubber used in automotive suspension bushings. By analyzing the problematic suspension bushings, the eleven candidate factors that influence squeak noise are selected: surface lubrication, hardness, vulcanization condition, surface texture, additive content, sample thickness, thermal aging, temperature, surface moisture, friction speed, and normal force. Through friction tests, the changes are investigated in frictional force and squeak noise occurrence according to various levels of the influencing factors. The degree of correlation between frictional force and squeak noise occurrence with the factors is determined through statistical tests, and the relationship between frictional force and squeak noise occurrence based on the test results is discussed. Squeak noise prediction models are constructed by considering the interactions among the influencing factors through both multiple logistic regression and neural network analysis. The accuracies of the two prediction models are evaluated by comparing predicted and measured results. The accuracies of the multiple logistic regression and neural network models in predicting the occurrence of squeak noise are 88.2% and 87.2%, respectively.

Frictional force apparatus

1976 ◽  
Vol 14 (6) ◽  
pp. 373-374
Author(s):  
Terril W. Mayes
Keyword(s):  
Frictional Force

Band Brake Squeal

1996 ◽  
Vol 118 (2) ◽  
pp. 190-197 ◽  
Author(s):  
M. Nakai ◽  
M. Yokoi
Keyword(s):  
Elastic Foundation ◽  
Frictional Force ◽  
Linear Analysis ◽  
Brake Squeal ◽  
Constant Frequency ◽  
Squeal Noise ◽  
Effective Treatments

The purpose of this paper is to investigate the squealing mechanism of band brakes in order to develop effective treatments for the reduction or elimination of squeal noise. With increasing rotational drum speed, squeal frequency increases up to a constant frequency. This constant squeal frequency coincides precisely with the frequency of instability obtained by a linear analysis of the motion of a band on an elastic foundation when the frictional force between the lining of the band and the drum is taken into account. Through experiments and analyses, it will be demonstrated that squeals are induced by the coupling between two modes of the band.

PERISTALTIC FLOW OF COUPLE-STRESS CONDUCTING FLUIDS THROUGH A POROUS CHANNEL: APPLICATIONS TO BLOOD FLOW IN THE MICRO-CIRCULATORY SYSTEM

2011 ◽  
Vol 19 (03) ◽  
pp. 461-477 ◽  
Author(s):  
DHARMENDRA TRIPATHI
Keyword(s):  
Frictional Force ◽  
Couple Stress ◽  
Amplitude Ratio ◽  
Circulatory System ◽  
Mechanical Efficiency ◽  
Peristaltic Flow ◽  
Porous Channel ◽  
Stress Parameter ◽  
Permeability Parameter ◽  
Conducting Fluids

The present investigation is devoted to study a theoretical investigation of the peristaltic flow of a couple-stress conducting fluids in a porous channel under the influence of slip boundary condition. This study is applicable to the physiological flow of blood in the micro-circulatory system, by taking account of the particle size effect. The expressions for axial velocity, pressure gradient, stream function, frictional force and mechanical efficiency are obtained under the small Reynolds number and the large wavelength approximations. Effects of different physical parameters reflecting permeability parameter, couple-stress parameter, Hartmann number as well as amplitude ratio on pumping characteristics, frictional force, mechanical efficiency and trapping of peristaltic flow pattern are studied. The computational and numerical results are presented in graphical form. On the basis of our discussion, it is concluded that pressure reduces by increasing the magnitude of couple-stress parameter, permeability parameter, slip parameter, whereas it enhances by increasing the magnitude of magnetic field and amplitude ratio.

PREDICATION FOR RELATIVE MOTION OF THE COLONOSCOPE IN COLONOSCOPY

2013 ◽  
Vol 13 (03) ◽  
pp. 1350023 ◽  
Author(s):  
WU BIN CHENG ◽  
MICHAEL A. J. MOSER ◽  
SIVARUBAN KANAGARATNAM ◽  
WEN JUN ZHANG
Keyword(s):  
Frictional Force ◽  
Frictional Contact ◽  
Linear Complementarity ◽  
Intestinal Wall ◽  
Deformable Objects ◽  
Dynamic Friction ◽  
Unilateral Constraints ◽  
Common Procedure ◽  
Mechanical Compliance ◽  
Signorini's Problem

Colonoscopy is common procedure frequently carried out. It is not without its problems, which include looping formation. Looping formation prevents the tip of the colonoscope itself from advancing, thus further probing induces a risk of perforation, significant patient discomfort, and failure of colonoscopy. During colonoscopy, the manipulated colonoscope for intubation in the colon goes through the friction between the colonoscope and the colon. Due to major frictional force, the sigmoidal colon forms looping with the scope during intubation. The interactive frictional force between the colon and the colonoscope is highly complex because of frictional contact between two deformable objects. In this paper, contact force computation was formulated into a linear complementarity problem (LCP) by linearizing Signorini's problem, which was adapted into non-interpenetration with unilateral constraints. Frictional force was computed by the mechanical compliance of finite element method (FEM) models with the consideration of dynamic friction between the colonoscope and the intestinal wall. Furthermore, we presented a mathematical model of the elongation of the colon that predicts the motion of scope relative to the intestinal wall in colonoscopy.

Motion of masses with asymmetric and symmetric friction. Application to fault sliding

2021 ◽  
Author(s):  
Rui Xiang Wong ◽  
Elena Pasternak ◽  
Arcady Dyskin
Keyword(s):  
Frictional Force ◽  
Normal Load ◽  
Power Spectra ◽  
Inertial Force ◽  
Friction Reduction ◽  
Relative Mass ◽  
Hydraulic Fractures ◽  
Driving Frequency ◽  
Stick Slip ◽  
Friction Forces

<p>This study analyses a situation when a geological fault contains a section of anisotropic gouge with inclined symmetry axes (e.g. inclined layering), Bafekrpour et al. [1]. Such gouge in a constrained environment induces, under compression, asymmetric friction (different friction forces resisting sliding in the opposite directions). The rest of the gouge produces conventional symmetric friction. A mass-spring model of the gouge with asymmetric and symmetric friction sections is proposed consisting of a mass with asymmetric friction connected through a spring to another mass with symmetric friction. These masses are set on a base subjected to vibration. A parametric analysis is performed on this system. Two distinct characteristic regimes were observed: <em>recurrent movement</em> resembling stick-slip motion similar to predicted by [2] and <em>sub-frictional movement</em>. Recurrent movement arises when the inertial force is sufficient to overcome frictional force of a block with symmetric friction. Sub-frictional movement occurs when the inertial force is not sufficient to overcome frictional force of an equivalent system with only symmetric friction. The sub-frictional movement is produced by the force in the connecting spring increased due to the movement of the asymmetric friction block in the direction characterised by low friction. We formulate the criterion at which sub-frictional movement occurs. The occurrence of sub-frictional depends upon the relative mass of the symmetric and asymmetric friction sections, as well as the amplitude and driving frequency of the excitation. Power spectra of the produced vibrations are determined for both regimes. The results can shed light on mechanisms of sliding over pre-existing discontinuities and their effect on seismic event generation and propagation of hydraulic fractures in the presence of discontinuities.</p><p>[1] Bafekrpour,<strong> </strong>E., A.V. Dyskin, E. Pasternak, A. Molotnikov and Y. Estrin (2015), Internally architectured materials with directionally asymmetric friction. <em>Scientific Reports</em>, 5, Article 10732.</p><p>[2] Pasternak, E. A.V. Dyskin and I. Karachevtseva, 2020. Oscillations in sliding with dry friction. Friction reduction by imposing synchronised normal load oscillations. <em>International Journal of Engineering Science</em>, 154, 103313.</p><p><strong>Acknowledgement</strong>. AVD and EP acknowledge support from the Australian Research Council through project DP190103260.</p>

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