scholarly journals Development of the scheme and method for measuring the characteristics of the friction areas in the car wheel contact

2021 ◽  
Vol 2061 (1) ◽  
pp. 012018
Author(s):  
E V Balakina ◽  
I V Sergienko ◽  
D S Sarbaev
Keyword(s):  
Sliding Friction ◽  
Rotation Axis ◽  
Static Friction ◽  
Solid Support ◽  
Reference Plane ◽  
Research Results ◽  
Contact Patch ◽  
Main Plane ◽  
The Moment ◽  
Patch Length

Abstract The aim of the research is to develop and implement a scheme and method for measuring the characteristics of static and sliding friction areas in the contact patch of an elastic wheel with a solid support when they appear, exist and disappear. The characteristics are understood as: the relative location of static and sliding friction in relation to the vector of the translational speed of the wheel axis; their size and location in the contact patch when they appear, spread and disappear; the values of the moments on the wheel, corresponding to the appearance, spread and disappearance of static and sliding friction. A scheme and a method for measuring these characteristics have been developed and implemented. The measurements are indirect. It has been experimentally established that, in the general case, the geometric center of static friction in the contact patch moves towards the moment acting in the plane of the wheel rotation relative to the rotation axis by an amount proportional to the moment. The maximum value of this displacement according to the moment that is maximum in terms of sliding conditions, and is one third of the contact patch length for all types and conditions of a solid support. The research results are valid for elastic wheels with a radial stiffness not exceeding 12000000 N/m, the main plane of which is perpendicular to the reference plane. The research results can find application in design modeling of stability and controllability of vehicles.

Multiple Reflow Influence over the FeCoCrAlTiCuNiMo Coating Obtained by Plasma Metallization on its Wear Resistance under Dry Friction

2021 ◽  
Vol 410 ◽  
pp. 475-481
Author(s):  
Anvar M. Kadyrmetov ◽  
Dmitri A. Popov ◽  
Yevgeny V. Snyatkov
Keyword(s):  
Wear Resistance ◽  
Dry Friction ◽  
Sliding Friction ◽  
Plasma Jet ◽  
Dry Sliding ◽  
Research Results ◽  
Open Atmosphere ◽  
Multicomponent Coating ◽  
Dry Sliding Friction

The article presents the research results of the plasma jet multiple reflow effect over the multicomponent coating FeCoCrAlTiCuNiMo, obtained by plasma metallization in an open atmosphere, on its wear resistance under dry sliding friction. The research results indirectly confirm the influence of the coating entropy over the wear resistance increasing along of the reflow number growth.

DIFFERENTIAL EQUATIONS FOR TRAIN STARTING WITH ELASTIC CONNECTIONS

2021 ◽  
Vol 2 ◽  
pp. 18-26
Author(s):  
I.P. POPOV
Keyword(s):  
Mathematical Model ◽  
Differential Equations ◽  
Friction Force ◽  
Static Friction ◽  
Longitudinal Vibrations ◽  
Maximum Tension ◽  
Inert Mass ◽  
The Moment ◽  
Elastic Couplings ◽  
Selection Of

The starting mode for the train is the most difficult. An effective method of pulling is the selection of coupling clearances. In this case, the cars are set in motion sequentially and the inert mass, as well as the static friction force immediately at the moment of starting, are minimal. This method has two significant drawbacks - a small fixed value of the gaps in the couplings and the shock nature of the impulse transfer. These disadvantages can be avoided by using elastically deformable couplings. The aim of this work is to construct a mathematical model of "easy" starting of a train with elastic couplings. The softening of the train start-off mode is essentially due to the replacement of the simultaneous start-off of the sections with alternate ones. To exclude longitudinal vibrations of the composition, after reaching the maximum tension of the coupling, the possibility of its harmonic compression should be mechanically blocked.

scholarly journals Calculation and AFM Experimental Research on Slip Friction for Unlubricated Spherical Contact with Roughness Effect

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1428
Author(s):  
Shengguang Zhu ◽  
Liyong Ni
Keyword(s):  
Friction Force ◽  
Sliding Friction ◽  
Static Friction ◽  
Friction Model ◽  
Rigid Sphere ◽  
Roughness Effect ◽  
Force Microscopy ◽  
Comparison Results ◽  
Experimental Values ◽  
Calculation Models

Previous research on friction calculation models has mainly focused on static friction, whereas sliding friction calculation models are rarely reported. In this paper, a novel sliding friction model for realizing a dry spherical flat contact with a roughness effect at the micro/nano scale is proposed. This model yields the sliding friction by the change in the periodic substrate potential, adopts the basic assumptions of the Greenwood–Williamson random contact model about asperities, and assumes that the contact area between a rigid sphere and a nominal rough flat satisfies the condition of interfacial friction. It subsequently employs a statistical method to determine the total sliding friction force, and finally, the feasibility of this model presented is verified by atomic force microscopy friction experiments. The comparison results show that the deviations of the sliding friction force and coefficient between the theoretical calculated values and the experimental values are in a relatively acceptable range for the samples with a small plasticity index (Ψ ≤ 1).

Collision of two coins on a horizontal surface

2021 ◽  
Vol 57 (1) ◽  
pp. 015009
Author(s):  
Rod Cross
Keyword(s):  
Friction Force ◽  
Sliding Friction ◽  
Static Friction ◽  
Video Camera ◽  
Horizontal Surface ◽  
Collision Process ◽  
Oblique Angle ◽  
Billiard Ball ◽  
Air Table

Abstract Oblique angle collisions of two penny coins on a smooth, horizontal surface were filmed with a video camera to investigate the physics of the collision process. If one of the coins is initially at rest, then the two coins emerge approximately at right angles, as commonly observed in billiard ball collisions and in puck collisions on an air table. The coins actually emerged at an angle less than 90 degrees due to friction between the coins, which also resulted in both coins rotating after the collision. At glancing angles, the friction force was due to sliding friction. At other angles of incidence the coins gripped each other and the friction force was then due to static friction.

Internal methyl rotation and molecular structure of trifluorotoluenes: microwave rotational spectra of 2,3,4- and 2,4,5-trifluorotoluene

2020 ◽  
Vol 98 (6) ◽  
pp. 543-550 ◽  
Author(s):  
K.P. Rajappan Nair ◽  
Sven Herbers ◽  
Daniel A. Obenchain ◽  
Jens-Uwe Grabow
Keyword(s):  
Internal Rotation ◽  
Rotation Axis ◽  
Molecular Constants ◽  
Methyl Carbon ◽  
Rotational Spectra ◽  
Pulsed Jet ◽  
Principal Axes ◽  
The Moment ◽  
Centrifugal Distortion Constants ◽  
Methyl Rotation

The microwave rotational spectra of 2,3,4- and 2,4,5-trifluorotoluenes, along with all 13C isotopic species in natural abundance, have been recorded in the frequency range 8–27 GHz employing pulsed-jet Fourier transform microwave spectroscopy. The analysis of the spectra in the lowest torsional state has yielded the rotational constants, centrifugal distortion constants, three-fold barrier to methyl rotation, and the direction of the internal rotation axis in the moment of inertia principal axes systems of these trifluorotoluenes. For both molecules, the molecular constants of their eight isotopologues have been used to obtain the substitution rs structures of the ring and the methyl-carbon. The potential barriers hindering the internal rotation of the methyl top in 2,3,4- and 2,4,5-trifluorotluene are 2.5878(80) and 2.2809(23) kJ/mol, respectively.

scholarly journals Critical shoe contact area ratio for sliding on a tennis hard court

2017 ◽  
Vol 232 (2) ◽  
pp. 112-121 ◽  
Author(s):  
John Eric Goff ◽  
Luke Boswell ◽  
Daniel Ura ◽  
Mark Kozy ◽  
Matt J Carré
Keyword(s):  
Friction Coefficient ◽  
Contact Area ◽  
Sliding Friction ◽  
Static Friction ◽  
Area Ratio ◽  
Critical Ratio ◽  
Static Friction Coefficient ◽  
The Creation ◽  
Contact Area Ratio

Dimples have been used in the design of some modern tennis shoe outsoles to enhance sliding ability on hard courts. Experiments were performed with bespoke rubber samples possessing various numbers of holes, which served to simulate dimples in tennis shoe treads. The aim of the research was to assess the effect of contact area on sliding friction. As the ratio of holes to solid rubber increased, a critical ratio was reached whereby the static friction coefficient decreased by more than 11% for tread-to-court pressures comparable to real tennis play. Although this study analyzed bespoke rubber samples and not actual tennis shoe treads, shoe manufacturers should be interested in the existence of a critical dimple ratio that could aid them in the creation of tennis shoes suited for sliding on hard courts.

AFM Interaction Forces of Lubricity Materials Surface

2012 ◽  
Vol 528 ◽  
pp. 95-98
Author(s):  
Xue Feng Li ◽  
Chu Wu ◽  
Shao Xian Peng ◽  
Jian Li
Keyword(s):  
Atomic Force Microscopy ◽  
Friction Force ◽  
Sliding Friction ◽  
Static Friction ◽  
Adhesive Force ◽  
New Method ◽  
Interaction Forces ◽  
Scanning Angle ◽  
Force Microscopy ◽  
Atomic Force

Micro interaction forces of lubricity surface of silicon and mica were studied using atomic force microscopy (AFM). From different scanning angle and bisection distance of the AFM, a new method of measuring micro static friction of lubricity surface materials was investigated. Results show that the micro coefficients of static and sliding friction of mica are less than the silicon, but the adhesive force is bigger. The mechanism of friction force of the two lubricity materials was discussed.

scholarly journals Investigation of the components of the cornering resistance of a tracked vehicle on a solid support base

2021 ◽  
Vol 1 (2) ◽  
pp. 51-62
Author(s):  
B.V. Padalkin ◽  
Keyword(s):  
Mathematical Model ◽  
Reaction Force ◽  
Vertical Axis ◽  
Support Surface ◽  
Tracked Vehicle ◽  
Tracked Vehicles ◽  
Contact Patch ◽  
Minimum Number ◽  
The Moment ◽  
Propulsion Unit

The purpose of the study is to increase the completeness and reliability of approaches to deter-mining the components of the cornering resistance a tracked vehicle, as well as to create a method for their assessment, which will be suitable for practical calculations. The article analyzes two components of the moment of cornering resistance of the tracked vehi-cle, which can be distinguished if we consider the interaction of the caterpillar with the support base through separate contact spots (active sections of the tracks located under the road wheels). The first component arises from the linear movement of the active sections of the tracks. The second is caused by the rotational movement of the contact patch about the vertical axis. The paper presents a mathematical model of the interaction of the propeller and a dense support base, which makes it possible to study the dependence of the components of the moment of corner-ing resistance on the geometric parameters of the undercarriage of a tracked vehicle. The horizontal reaction force in this case is presented as a function of the slip coefficient. The possibility of realiz-ing various adhesion qualities of the propulsion unit in the longitudinal and transverse directions of sliding is provided. The model assumes a preliminary division of the contact patch into a finite number of elementary areas. Since the number of elementary sites affects the result, the article con-ducted a study to determine the minimum number of sites to ensure acceptable accuracy. An analysis of the expressions available in the literature was carried out to determine the speci-fied component of the cornering resistance. The new empirical relationships that better agree with the mathematical model were proposed. The study of several existing tracked vehicles, differing in the mass and size of the track support surface, made it possible to conclude that it is advisable to take into account the moment of cornering resistance of the contact patch for various types of tracked vehicles.

scholarly journals Relationships among the contact patch length and width, the tire deflection and the rolling resistance of a free-running wheel in a soil bin facility

2015 ◽  
Vol 13 (2) ◽  
pp. e0211 ◽  
Author(s):  
Parviz Tomaraee ◽  
Aref Mardani ◽  
Arash Mohebbi ◽  
Hamid Taghavifar
Keyword(s):  
Rolling Resistance ◽  
Contact Length ◽  
Analysis Of Covariance ◽  
Image Processing Technique ◽  
Inflation Pressure ◽  
Wheel Load ◽  
Contact Patch ◽  
Patch Width ◽  
Soil Bin ◽  
Patch Length

<p>Qualitative and quantitative analysis of contact patch length-rolling resistance, contact patch width-rolling resistance and tire deflection-rolling resistance at different wheel load and inflation pressure levels is presented. The experiments were planned in a randomized block design and were conducted in the controlled conditions provided by a soil bin environment utilizing a well-equipped single wheel-tester of Urmia University, Iran. The image processing technique was used for determination of the contact patch length and contact patch width. Analysis of covariance was used to evaluate the correlations. The highest values of contact length and width and tire deflection occurred at the highest wheel load and lowest tire inflation pressure. Contact patch width is a polynomial (order 2) function of wheel load while there is a linear relationship between tire contact length and wheel load as well as between tire deflection and wheel load. Correlations were developed for the evaluation of contact patch length-rolling resistance, contact patch width-rolling resistance and tire deflection-rolling resistance. It is concluded that the variables studied have a significant effect on rolling resistance.</p>

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