scholarly journals Evaluation of the Usefulness of Friction Tester Vehicles to Operate on Runway Pavement Surfaces

2016 ◽  
Vol 39 (1) ◽  
pp. 43-50
Author(s):  
Mariusz Wesołowski ◽  
Piotr Barszcz ◽  
Krzysztof Blacha
Keyword(s):  
Coefficient Of Friction ◽  
Friction Measurement ◽  
Limit Values ◽  
Technical Problems ◽  
Normative Documents ◽  
Measuring Devices ◽  
Friction Tester ◽  
Flight Operations ◽  
Operation Process ◽  
Roughness Measurements

Abstract The assessment correctness of runway pavement surfaces is a crucial element ensuring safety during flight operations. Foreign and national normative documents specify the required values of coefficients of friction both for designed (new) and utilized runway pavement surfaces and/or those subject to planned renovation works. What is more, the above mentioned documents determine the minimum (limit) values for operated runway pavement surfaces. Furthermore, they also describe the general requirements as regards measuring devices applied to specify the roughness of runway pavement surfaces. The accepted repeatability (Equipment Variation) of coefficient of friction measurement is not sufficient to approve the device for roughness measurements of aerodrome functional elements. Due to this fact the device is authorized to take measurements of coefficient of friction under the condition that it is preceded by certain studies carried out in order to establish its usefulness. These research consist inter alia of the device evaluation in view of devices authorized to perform measurements, using statistical apparatus. Final evaluation of instrument usefulness includes additionally the whole gamut of technical problems associated with the operation process, its preparation, calibration (checking) before taking measurements and the measurements themselves.

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

2015 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Goutam Chandra Karar ◽  
Nipu Modak
Keyword(s):  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Epoxy Composite ◽  
Normal Load ◽  
Crumb Rubber ◽  
The Other ◽  
Reciprocating Motion ◽  
Molding Process ◽  
Friction Tester ◽  
The Coefficient Of Friction

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

Investigation of the causes of damage to freight cars during disbanding on non-mechanized sorting slides and development of measures to prevent them

2021 ◽  
pp. 4-13
Author(s):  
S. V. Tankeev ◽  
◽  
A. E. Kolodin ◽  
V. B. Sverdlov ◽  
A. V. Nazarov ◽  
...  
Keyword(s):  
Low Power ◽  
Coefficient Of Friction ◽  
Damage Assessment ◽  
Laboratory Tests ◽  
Rolling Stock ◽  
Third Body ◽  
Normative Documents ◽  
The Coefficient Of Friction ◽  
Loading And Unloading ◽  
The Relationship

The damage assessment of freight cars during shunting and loading and unloading operations was made. The need to review the normative documents regulating the relationship between the owners of rolling stock, owners of non-public tracks and the carrier is noted. The reasons for formation of damage on the wheel pairs of freight cars when disbanding on low-power sorting slides are considered. The conditions for ensuring the deceleration of detachments on non-mechanized sorting slides without damaging the wheels are determined. The analysis of methods for ensuring braking on low-power slides is carried out. A method was chosen to ensure the wheel set rotation by introducing a third body between the rubbing surfaces during the braking of cars, which will take over a part of the resulting heat flow, reducing the temperature and increasing the coefficient of friction in the «wheel-rail» contact zone. A method is proposed to provide braking on the non-mechanized sorting slide during shoe braking by applying a friction compound to a non-working rail. Laboratory tests were carried out, which showed that the introduction of a friction additive can achieve the necessary coefficient of friction to comply with the standard parameters of deceleration of the car in the braking zone.

Tribometer for Dry Friction Measurement

1999 ◽  
Author(s):  
Marc Brandl ◽  
Friedrich Pfeiffer
Keyword(s):  
Coefficient Of Friction ◽  
Dry Friction ◽  
Stribeck Curve ◽  
Body System ◽  
Friction Measurement ◽  
Detailed Model ◽  
The Coefficient Of Friction ◽  
Simulation Results ◽  
Multi Body

Abstract This paper deals with the measurement of dry friction. A tribometer was developed in order to identify both the sticking and the sliding coefficient of friction. The aim was to determine the so called Stribeck-curve of any material in contact. The design of the plant is presented. Avoiding errors in recalculating the coefficient of friction, a detailed model of the plant as a multi body system with motor feedback was generated. Advantages of the tribometer are shown in simulations. Some results of measurements in comparison with simulation results are presented.

Graphical method for determining of limit and permissible values of drawing and friction coefficients, stress, drawing angle and delta-criterion for shape of plastic deformation zone

2021 ◽  
pp. 55-66
Author(s):  
G.N. Gur’yanov
Keyword(s):  
Safety Factor ◽  
Coefficient Of Friction ◽  
Plastic Deformation Zone ◽  
Tension Stress ◽  
Abscissa Axis ◽  
Limit Values ◽  
Drawing Stress ◽  
Optimal Value ◽  
The Coefficient Of Friction ◽  
Drawing Angle

The maximum and permissible values of the coefficients of drawing and friction, the Delta criterion of the shape of the deformation center, the index of the deformed state, the angle and drawing stress are determined graphically for different models of hardening and values of the anti-tension stress. For the determination, cartesian graphs were used, on the ordinate axis of which the desired indicators are located, and on the abscissa axis the values of the I.L. Per lin safety factor obtained by varying the extraction coefficient. The permissible values of the drawing coefficient and drawing stress decrease with the growth of the safety factor of I.L. Perlin. The dependence of the limit and permissible values of the Delta criterion for the optimal value of the drawing angle on the deformation parameters and the harden ing model is shown. The maximum and permissible values of the coefficient of friction are higher at the optimal value of the drawing angle. For the first time, the possibility of increasing the limit value of the coefficient of friction from the action of anti-gravity is established. The limit and permissible values of the coefficient of friction decrease with the increase in the value of the coefficient of drawing and increase with the increase in the coefficient of hardening k. Curves for the dependences of the safety factor, the stress state indicator and the absolute safety margin Zap on the value of the drawing angle fix small and large values of the limit drawing angle on the abscissa axis. Small limit values of the drawing angle do not differ significantly in value for different values of the drawing and hardening coefficients, in contrast to large limit values of the angle. The action of counter-gravity increases the small limit angles and decreases the large limit angles. Determination of the limit and permissible values of the coefficients of drawing and friction, the Delta criterion, stress and drawing angle contributes to the rational choice of modes of deformation of the wire (bar).

scholarly journals Analysis of the Actual Contact Surface of Selected Aircraft Tires with the Airport Pavement as a Function of Pressure and Vertical Load

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 591
Author(s):  
Mariusz Wesołowski ◽  
Krzysztof Blacha ◽  
Paweł Pietruszewski ◽  
Paweł Iwanowski
Keyword(s):  
Contact Area ◽  
Contact Surface ◽  
Load Capacity ◽  
Surface Friction ◽  
Vertical Load ◽  
Tire Pressure ◽  
Wheel Load ◽  
Friction Tester ◽  
Flight Operations ◽  
Research Studies

The contact surface of the wheel with the airport surface is important for the safety of flight operations in the ground manoeuvring area. The area of the contact surface, its shape and stress distribution at the pavement surface are the subject of many scientists’ considerations. However, there are only a few research studies which include pressure and vertical load directly and its influence on tire-pavement contact area. There are no research studies which take into account aircraft tires. This work is a piece of an extensive research project which aims to develop a device and a method for continuous measurement of the natural airport pavement’s load capacity. One of the work elements was to estimate the relationship between wheel pressure and wheel pressure on the surface, and the area of the contact surface. The results of the research are presented in this article. Global experience in this field is cited at the beginning of the article. Then, the theoretical basis for calculating the wheel with the road surface contact area was presented. Next, the author’s research views and measurement method are presented. Finally, the obtained test results and comments are shown. The tests were carried out for four types of tires. Two of them were airplane tires from the PZL M28 Skytruck/Bryza and Sukhoi Su-22 aircraft. Two more came from the airport ASFT (airport surface friction tester) friction tester-one smooth ASTM; the other smooth retreaded type T520. The tires were tested in a pressure range from 200 to 800 kPa. The range of vertical wheel load on the pavement was 3.23–25.93 kN for airplane tires, and 0.8–4.0 kN for friction tester tires. The tests proved a significant influence of the wheel pressure value and wheel pressure on the surface on the obtained contact surface area of the wheel with the surface. In addition, it was noted that the final shape and size of the contact surface is affected by factors other than wheel pressure, tire pressure and dimensions.

Research on Sliding Layer of Cross-Tensioned Prestressed Concrete Pavement

2014 ◽  
Vol 1004-1005 ◽  
pp. 1486-1491
Author(s):  
De Chen ◽  
Sen Han ◽  
Cheng Ling ◽  
Dong Sheng Zhang ◽  
Fu Yang Guan
Keyword(s):  
Coefficient Of Friction ◽  
Prestressed Concrete ◽  
Concrete Pavement ◽  
Plastic Film ◽  
Analysis Method ◽  
Material Parameters ◽  
Friction Tester ◽  
Optimum Material ◽  
Stress And Deformation ◽  
Testing Speed

A coefficient of friction tester (CFT) for the cross-tensioned prestressed concrete pavement (CTCP) sliding layer was designed and developed basing on the Amonton law. The CFT can obtain precise values of the CTCP sliding layer coefficient of friction. Meanwhile, the sand and polyethylene plastic film (SPPF) sliding layer which has already been used in CTCP experimental road was tested using the CFT. The best testing speed (1mm/min) for CFT was obtained with applying regression analysis method to the results. The optimum material parameters for the SPPF are the combination of 2.6 fineness modulus of sand, 10mm thickness of sliding layer, and 3 μm thickness of polyethylene plastic film (PPF). The optimum materials combination of the SPPF provides minimum coefficient of friction to the CTCP sliding layer which can reduce the stress and deformation of the CTCP slab.

First Observation of Elastic Plowing in Nanofriction

2005 ◽  
Author(s):  
Z. Charles Ying ◽  
Stephen M. Hsu
Keyword(s):  
Friction Force ◽  
Coefficient Of Friction ◽  
Cross Sectional Area ◽  
Elastic Contact ◽  
Sectional Area ◽  
Device Design ◽  
Friction Measurement ◽  
Cross Sectional ◽  
Elastic Regime ◽  
Series Of Experiments

Accurate friction measurement at nanoscale is critical in reliable micro- and nano-device design. Different values of coefficient of friction (COF) have been reported in the literature for the same material when different instruments and tip sizes were used [1–3]. We have conducted a series of experiments to delineate the effects of different tip sizes and shapes on friction as a function of load and found that friction force values under the elastic contact regime for various tips can be unified when plotted against the tip cross-sectional area in the direction of sliding. This observation implies a volumetric dependence of friction that has not been reported before in the elastic regime.

scholarly journals The level of noise In the surroundings of public transport vehicles

2019 ◽  
Vol 20 (1-2) ◽  
pp. 128-131
Author(s):  
Karolina Trzyniec
Keyword(s):  
Public Transport ◽  
Noise Levels ◽  
Limit Values ◽  
Normative Documents ◽  
The City ◽  
Excessive Noise

The article discusses the problem of excessive noise levels In the city. Especially, this concerns Communications noise, which is caused by public transport, such as: trans, buses and trams. The level of noise emitted by these vehicles was analyzed, ta king into account different hours and the measured values were compared with the limit values set In the normative documents (the Regulation of the Minister of the Environment of June, 14, 2017)

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