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Friction and Wear in Extreme Conditions
Published in Ahmed Abdelbary, Extreme Tribology, 2020
In general, tribometers (or tribotesters) are used as instruments that perform tribological measurements, such as the coefficient of friction, friction force, wear volume, and contact temperature between two rubbing surfaces. The investigation of friction and wear behavior of materials at elevated temperatures has become increasingly important, especially for the development of power plants and internal combustion engine industries. High temperature tribometers are used for studying friction and wear properties at elevated temperatures, up to 1500ºC. Such types of tribometers generally obtain high temperatures by using insulated chamber or furnace equipped with heating elements.
Specific testing techniques in tribology: laboratory techniques for evaluating friction, wear, and lubrication
Published in J.-P. Celis, P. Ponthiaux, Testing tribocorrosion of passivating materials supporting research and industrial innovation: Handbook, 2017
The equipment which enables the measurement of tribological properties such as friction, wear damage and load carrying properties is called a tribometer. Basically, a tribometer will ‘rub’ (Greek: tribos) two bodies against each other, creating a relative motion. This occurs with a contact load or contact pressure between the bodies and meanwhile the force that resists motion is measured as the friction force. Other relevant parameters that can also be measured are temperatures, acoustic signals, electrical or electrochemical data, etc.
Monodispersed calcium oxalate as highly effective support filler in PMMA-based nanocomposite
Published in Journal of Dispersion Science and Technology, 2023
Khalida Akhtar, Shahana Abad, Syed Sajjad Ali Shah, Zia Ullah Khan, Naila Zubair, Hina Khalid
Tribometer measured the tribological quantities, such as friction and wear of several materials in the presence of applied load and sliding distance at a constant temperature. The wear resistance was calculated for each composite in the dry condition employing a ball-on-disk tribometer setup (Figure 1). Before the experiments, the mild steel ball was cleaned by sonicating them for 5–10 min in NaOH and HCl to remove the acid and base soluble impurities. The as-fabricated composites were shaped into stubs/disks of around 3 mm in diameter. The ball was fixed in the static upper support and rubbed against the nanocomposite disk. The optimized sliding distance of 300 ± 001 m was kept constant during the experimentation. The engine speed has been adjusted to 200 rpm. The measurements were made with minimum and maximum loads of 2 and 8 N, respectively. The analysis of frictional force was performed with the aid of a load transducer (Shimpo, Japan) coupled with a computer, that noted the experimental data constantly with the assistance of suitable software. The acquired data on friction force was further used to estimate the coefficient of friction. The stubs/disk density was calculated by using a densimeter.
Influence of non-dry condition creep curves in switch negotiation
Published in Vehicle System Dynamics, 2023
Ingemar Persson, Maksym Spiryagin, Carlos Casanueva
Tribometers are devices that can measure friction force developed between surfaces in a relative motion. Tribometers can serve several purposes, from measuring sliding friction to evaluating lubricants or monitoring surface contamination. In rail applications, specific tribometers have been developed [4,5] and are mostly used for experimental determination of creep curves [6,7]. In this study, the hand operated tribometer (HO Tribo) [5] has been used to measure the friction coefficient from the field. The tribometer is shown in Figure 1.
Quantifying the uncertainty in tribometer measurements on walkway surfaces
Published in Ergonomics, 2021
Gunter P. Siegmund, Mark G. Blanchette, John R. Brault, Dennis D. Chimich, Benjamin S. Elkin
Numerous factors contribute to the uncertainty of tribometer measurements, including elements of the test method (e.g. number and direction of tests), operator performance, tribometer condition and function (e.g. wear and lubrication of moving parts), test foot type (e.g. material, shape, and groove pattern), test foot preparation, environmental conditions (e.g. temperature and humidity), test sample properties and the time between tests (Marpet 2002; Flynn 2006). The uncertainty generated by most of these factors cannot be quantified by a single user of a single tribometer unit, and therefore quantifying uncertainty is commonly done using one of two approaches (Deldossi and Zappa 2009). One approach is based on a statistical experimental design that attempts to quantify uncertainty directly through multiple measurements by multiple laboratories of one or more test items (ISO 1994; ASTM 2016a). This empirical approach yields measures of a method’s repeatability (same laboratory, same operator, same equipment) and reproducibility (different laboratories, different operators, different equipment). This approach captures the main effects of and interactions among variables included in the experimental design but misses the contribution of other variables not included in the experimental design. The second approach is based on estimating the uncertainty associated with all input variables and then combining these individual uncertainties (usually as the square root of a weighted sum of squares) to estimate an expanded uncertainty (e.g. JCGM 100-2008). In this approach, the individual uncertainties can be either experimentally measured or estimated from detailed knowledge if the measurement is not feasible. Although this approach captures the effects of variables that are difficult to incorporate into an experiment, it depends on the quality of the estimates (and the estimators) and can miss interactions between variables.