Journal articles: 'Coefficient of static friction'

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Rusinek, R., and M. Molenda. "Static and kinetic friction of rapeseed." Research in Agricultural Engineering 53, No. 1 (January 7, 2008): 14–19. http://dx.doi.org/10.17221/2129-rae.

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he present paper examines the static and kinetic coefficient of friction of rapeseed. The project utilized two methods of determination of coefficient of friction of rapeseed: according Eurocode 1 (kinetic) in direct shear test and (static) in model silo. Samples of rapeseed in a range of moisture content from 6 to 15% w.b. were used and the tests were performed for galvanized steel, stainless steel and concrete B 30. Coefficient of friction for both steel types approached stable value for all levels of moisture content w.b. in a range from 0.11 to 0.18, for concrete B 30 it was found in a range from 0.25 to 0.43. The coefficient of static friction found in model silo decreased with an increase in vertical pressure from 0.3 to 0.2 for first loading, while in subsequent loading cycles decreased from 0.2 to 0.1.

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Pluta, Zdzisław, and Tadeusz Hryniewicz. "Adequate Force Characteristics of a Friction System." International Letters of Chemistry, Physics and Astronomy 13 (September 2013): 20–36. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.13.20.

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In the paper, at first some remarks concerning friction are presented by the definition of the friction itself, as well as its essential force characteristics. An adequate definition of friction is introduced, and moreover a correct its characteristics. Next the statics, dynamics, and kinematics of the friction system is given, forming the force characteristics of this system for each of the mechanical behaviours, taking into account real inertia forces of the body under friction. Three types of coefficients of sliding friction have been separated, namely: coefficient of static friction, dynamic friction, and kinematic friction. Then the comparative analysis of existent and new knowledge on the force characteristics of friction process has been presented. The consideration on how to determine the coefficient of static friction has also been carried out. Reflections on the possibilities to form further force characteristics of the friction process are presented to develop this work with some final remarks directing the attention on the conditions of development of science on friction.

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Todorović, P. M., M. Blagojević, D. Vukelić, I. Mačužić, M. Jeremić, A. Simić, and B. Jeremić. "Static coefficient of rolling friction under heating." Journal of Friction and Wear 34, no. 6 (November 2013): 450–53. http://dx.doi.org/10.3103/s1068366613060123.

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Qiu, Ming Ming, Han Zhao, and Fa Ming Sha. "The Simulation Research of Dual Clutch Transmission's Starting Process Based on Dynamic Friction Coefficient." Applied Mechanics and Materials 401-403 (September 2013): 320–25. http://dx.doi.org/10.4028/www.scientific.net/amm.401-403.320.

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Introduce the dynamic friction coefficient of clutch friction plate. Establish Mathematical model of starting process, carried out vibration analysis for frictional sliding process systematically, validated the analysis using Matlab/simulink software. Meanwhile, compared with the starting process by static friction coefficient. The results show that using dynamic friction coefficient to analyse starting process conforms to the actual working condition.

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Chang, W. R., I. Etsion, and D. B. Bogy. "Static Friction Coefficient Model for Metallic Rough Surfaces." Journal of Tribology 110, no. 1 (January 1, 1988): 57–63. http://dx.doi.org/10.1115/1.3261575.

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The friction force required to shear interface bonds of contacting metallic rough surfaces is calculated, taking into account the prestress condition of contacting asperities. The surfaces are modeled by a collection of spherical asperities with Gaussian height distribution. Previous analyses for adhesion force and contact load of such surfaces are used to obtain the static friction coefficient. It is shown that this coefficient is affected by material properties and surface topography, and that it actually depends on the external loading contrary to the classical law of friction.

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Li, Xiao Guang, and Ping Zhao. "Study on Tribological Performances of Friction Plate on MW Wind Power." Applied Mechanics and Materials 217-219 (November 2012): 314–17. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.314.

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The effects of contact pressure and sliding velocity and different environment conditions on the frictional coefficient of friction plate on MW wind power were studied by fatigue testing machine. The results show that the coefficient of static friction and difference between static and dynamic reduced with the increase of sliding speed, and reduced first and then increased and then reduced with the increase of contact pressure, and the change of dynamic friction coefficient was relatively flat with velocity and pressure under dry friction. The impact of water on the triological performance was the large, followed by oil when considering environment factors. Water and pressure and oil were the main influencing factors in considering all factors comprehensively.

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Wang, S., and K. Komvopoulos. "Static Friction and Initiation of Slip at Magnetic Head-Disk Interfaces." Journal of Tribology 122, no. 1 (June 8, 1999): 246–56. http://dx.doi.org/10.1115/1.555349.

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The apparent friction force and electric contact resistance at the magnetic head-disk interface were measured simultaneously for textured and untextured disks lubricated with perfluoropolyether films of different thicknesses. The initial stick time, representing the time between the application of a driving torque and the initiation of interfacial slip, was determined based on the initial rise of the apparent friction force and the abrupt increase of the electric contact resistance. Relatively thin lubricant films yielded very short initial stick times and low static friction coefficients. However, for a film thickness comparable to the equivalent surface roughness, relatively long initial stick times and high static friction coefficients were observed. The peak value of the apparent friction coefficient was low for thin lubricant films and increased gradually with the film thickness. The variations of the initial stick time, static friction coefficient, and peak friction coefficient with the lubricant film thickness and surface roughness are interpreted in the context of a new physical model of the lubricated interface. The model accounts for the lubricant coverage, effective shear area, saturation of interfacial cavities, limited meniscus effects, and the increase of the critical shear stress of thin liquid films due to the solid-like behavior exhibited at a state of increased molecular ordering. [S0742-4787(00)03101-5]

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Stoyanova, Raya, Sasho Aleksandrov, and Umme Kapanak. "Study of the influence of compressive force on the coefficients of friction for wool-containing fabrics." E3S Web of Conferences 207 (2020): 03003. http://dx.doi.org/10.1051/e3sconf/202020703003.

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Making use of appliance MXD-02, Labthink, China, coefficient of friction at rest with sliding tendency (static coefficient of friction) and coefficient of friction at sliding (dynamic coefficient of friction) for fabrics made of 100% wool as well as woolen fabrics with admixtures of polyamide and polyester were determined. The influence of the magnitude of normal pressure on the coefficients of friction was studied. Experiments taking into consideration the following different directions of relative fabric movement were performed: warp by warp threads, and warp by weft. An analysis of the obtained results was made.

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Changfu, Sui, and Sheng Xuanyu. "Fractal Transition Model in Predicting Static Friction Coefficient." Multidiscipline Modeling in Materials and Structures 5, no. 4 (October 1, 2009): 345–48. http://dx.doi.org/10.1163/157361109789807972.

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Yamada, Yoji, Nuio Tsuchida, Koji Imai, and Hiroaki Kozai. "Static Friction Coefficient Sensor for Controlling Grasping Force." IEEJ Transactions on Electronics, Information and Systems 112, no. 12 (1992): 743–48. http://dx.doi.org/10.1541/ieejeiss1987.112.12_743.

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Dunkin, John E., and Dae E. Kim. "Measurement of static friction coefficient between flat surfaces." Wear 193, no. 2 (May 1996): 186–92. http://dx.doi.org/10.1016/0043-1648(95)06706-x.

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Savenkov, Dmitriy, Oleg Kirischiev, Ylia Kirischieva, Tatiana Tupolskikh, Tatiana Maltseva, Magomed Magomedov, and Andrey Chistyakov. "Study of the nature of the dynamic coefficient of internal friction of grainmaterials." E3S Web of Conferences 135 (2019): 01102. http://dx.doi.org/10.1051/e3sconf/201913501102.

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The article highlights the issues related to the study of physical and mechanical characteristics of bulk materials, namely internal friction coefficients in static and dynamic modes. An innovative device of the carousel type for determining the frictional characteristics of bulk materials is described, which allows to implement the tasks of practical determination of dynamic coefficients of internal friction. Presented the program, methodology and results of research on the practical study of the internal friction coefficient of typical bulk products of agricultural production in the range of linear velocities of displacement of layers from 0 to 2.79 m/s, the reliability of which is not lower than 0.878.

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Kaliniewicz, Zdzisław, Krzysztof Jadwisieńczak, Zbigniew Żuk, Stanisław Konopka, Adam Frączyk, and Zbigniew Krzysiak. "Effects of Friction Plate Hardness and Surface Orientation on the Frictional Properties of Cereal Grain." International Journal of Food Science 2020 (November 15, 2020): 1–9. http://dx.doi.org/10.1155/2020/6639233.

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The objective of this study was to evaluate the effects of the friction plate hardness and surface orientation of a friction plate on the angle and coefficient of static friction of cereal kernels. The angle of static friction of kernels representing four major cereal species was measured on six friction plates with different hardness. The friction plates were placed in position where their surface orientation was perpendicular or parallel relative to their inclination tilt. The experimental material comprised the so-called flat seed units, where each unit consisted of three spaced kernels. The angle of static friction of every flat seed unit was measured with a dedicated device in three replications, and average values of that angle were calculated. The kernels’ angle of static friction varied considerably from 13° to 33° within the analyzed range of changes in the surface characteristics of friction plates. The average angle of static friction was influenced mainly by the surface orientation of the friction plate that came into contact with cereal kernels. The angle of static friction was 17.5% to 56.5% higher when the friction plate had perpendicular rather than parallel surface orientation. The frictional properties of kernels were less influenced by plate hardness, and clear relationships were not observed in this respect. The kernels’ coefficient of static friction remained fairly constant within the analyzed range of plate hardness values, and it was estimated at 0.4 on plates with a perpendicular surface orientation and at 0.3 on plates with a parallel surface orientation.

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Kovriga, V. V., A. S. Vasil'eva, and A. I. Malikov. "A method for determining the high-temperature coefficient of friction." Plasticheskie massy, no. 5-6 (July 17, 2021): 4–5. http://dx.doi.org/10.35164/0554-2901-2021-5-6-4-5.

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A method for estimating the coefficient of friction at high temperatures up to 220°C in the thermal chamber of a bursting machine has been developed. It is shown that the coefficient of kinetic friction with a change in temperature from 25°C to 220°C varies from 0.04 to 0.1. In the developed method, the coefficient of static friction and the coefficient of kinetic friction are determined. The coefficient of static friction at a temperature of 25°C to 220°C varies from 0.06 to 0.13.

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KUJAWA, Maciej, and Wojciech WIELEBA. "THE INFLUENCE OF A CONSTANT STATE OF DEFORMATION ON THE FRICTION COEFFICIENT IN SELECTED THERMOPLASTICS (POLYMER–STEEL PAIR)." Tribologia, no. 4 (August 31, 2017): 39–45. http://dx.doi.org/10.5604/01.3001.0010.5992.

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The effect of tensile deformation on polymer structures and their mechanical properties is described in various papers. However, the majority of articles are focused on high deformation (a few hundred percentiles) at increased temperature. It causes changes in orientation and the crystallinity ratio. The authors of this paper asses the influence of strain (max. 50%) on hardness and the coefficient of friction (polymer–steel A1 couple) for selected polymers. The deformation was conducted at room temperature and maintained during tests. There was a significant reduction (up to 50%) of hardness after deformation, in the case of all examined polymers. In the case of PE-HD, the coefficient of kinetic friction almost doubled its value (89% increase). The reduction of the coefficient of static friction for sliding pairs that include PTFE and PA6 was about 26% (in comparison with non-deformed polymer). For all investigated polymers, hardness increased over time (up to 40% after 24 hours). Coefficients of static and kinetic friction decreased in 24 hours (up to 29% coefficient of static friction and 19% coefficient of kinetic friction). The research shows that a small deformation causes changes in polymer properties. Moreover, these changes appear at room temperature directly after deformation.

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Rossi, Anthony M., Tina L. Claiborne, Gregory B. Thompson, and Stacey Todaro. "The Influence of Friction Between Football Helmet and Jersey Materials on Force: A Consideration for Sport Safety." Journal of Athletic Training 51, no. 9 (September 1, 2016): 701–8. http://dx.doi.org/10.4085/1062-6050-51.11.07.

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Context: The pocketing effect of helmet padding helps to dissipate forces experienced by the head, but if the player's helmet remains stationary in an opponent's shoulder pads, the compressive force on the cervical spine may increase. Objective: To (1) measure the coefficient of static friction between different football helmet finishes and football jersey fabrics and (2) calculate the potential amount of force on a player's helmet due to the amount of friction present. Design: Cross-sectional study. Setting: Laboratory. Patients or Other Participants: Helmets with different finishes and different football jersey fabrics. Main Outcome Measure(s): The coefficient of friction was determined for 2 helmet samples (glossy and matte), 3 football jerseys (collegiate, high school, and youth), and 3 types of jersey numbers (silkscreened, sublimated, and stitched on) using the TAPPI T 815 standard method. These measurements determined which helmet-to-helmet, helmet-to-jersey number, and helmet-to-jersey material combination resulted in the least amount of static friction. Results: The glossy helmet versus glossy helmet combination produced a greater amount of static friction than the other 2 helmet combinations (P = .013). The glossy helmet versus collegiate jersey combination produced a greater amount of static friction than the other helmet-to-jersey material combinations (P < .01). The glossy helmet versus silkscreened numbers combination produced a greater amount of static friction than the other helmet-to-jersey number combinations (P < .01). Conclusions: The force of static friction experienced during collisions can be clinically relevant. Conditions with higher coefficients of static friction result in greater forces. In this study, the highest coefficient of friction (glossy helmet versus silkscreened number) could increase the forces on the player's helmet by 3553.88 N when compared with other helmet-to-jersey combinations. Our results indicate that the makeup of helmet and uniform materials may affect sport safety.

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Espinosa, H. D., A. J. Patanella, and M. Fischer. "Dynamic Friction Measurements at Sliding Velocities Representative of High-Speed Machining Processes." Journal of Tribology 122, no. 4 (April 17, 2000): 834–48. http://dx.doi.org/10.1115/1.1310331.

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Understanding high speed machining processes requires knowledge of the dynamic friction response at the tool-workpiece interface, the high strain rate response of the workpiece material and its fracture mechanisms. In this paper, a novel experimental technique, consisting in the independent application of an axial static load and a dynamic torque, is used to investigate time resolved dynamic friction. Shear stress wave propagation along an input bar, pressing statically against an output bar, is analyzed. The quasi-static and kinetic friction coefficients of Ti-6Al-4V sliding against 1080 Steel, Al 6061-T6 sliding against 1080 Steel, and Al 6061-T6 sliding against Al 7075-T6, with various surface characteristics, are investigated. Sliding velocities up to 6.9 m/s are achieved. Surface roughness is varied to understand its role on the frictional response of the sliding interfaces. The dependence of friction coefficient on material strain-rate sensitivity is also assessed. Measured friction coefficients compared well with values reported in the literature using other experimental techniques. The experimental methodology discussed in this article provides a robust method for direct measurement of the quasi-static and dynamic friction coefficients representative of high-speed machining, metal-forming and ballistic penetration processes. [S0742-4787(00)01304-7]

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Schulson, Erland M. "Friction of sea ice." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, no. 2129 (August 20, 2018): 20170336. http://dx.doi.org/10.1098/rsta.2017.0336.

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Static and kinetic friction play a fundamental role in sea-ice mechanics. The coefficient of static friction increases with hold time under normal load and is modelled in terms of creep and fracture of asperities in contact. The coefficient of kinetic friction exhibits velocity strengthening at lower speeds and velocity weakening at intermediate speeds. Strengthening is modelled in terms of asperity creep and hardness; weakening is modelled in terms of a progressive increase in the true area of contact wetted by meltwater produced through frictional heating. The concept is introduced of contact size distribution in which the smallest contacts melt first, leading to the onset of weakening; the largest melt last, leading to a third regime of kinetic friction and again to strengthening where hydrodynamics governs. Neither the static nor the kinetic coefficient is significantly affected by the presence of sea water. The paper closes with a few implications for sea-ice mechanics. The paper is based largely upon a critical review of the literature, but includes a more quantitative, physics-based analysis of velocity strengthening and a new analysis of velocity weakening that incorporates parameters that describe the (proposed) fractal character of the sliding interface. This article is part of the theme issue ‘Modelling of sea-ice phenomena’.

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Geng, Lingxin, Jiewen Zuo, Fuyun Lu, Xin Jin, Chenglong Sun, and Jiangtao Ji. "Calibration and Experimental Validation of Contact Parameters for Oat Seeds for Discrete Element Method Simulations." Applied Engineering in Agriculture 37, no. 4 (2021): 605–14. http://dx.doi.org/10.13031/aea.14381.

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Highlights The static friction coefficient and rolling friction coefficient of oat seeds were calibrated by the discrete element method. Two representative oat varieties were selected. The hollow cylinder method and sidewall collapse method were used together to reduce the test error. Abstract . Hulless and shelled oat are two types of oat with major differences in physical appearance. To study the contact parameters between the two different oat seed types, these parameters were delineated with the discrete element method and graphic image processing technology. Using plexiglass as the contact material, the experiments used two different angle of repose measurement methods—hollow cylinder and collapse sidewall devices, to perform bench and simulation experiments on the two different oats. Under different measurement methods, bench experiments measured the angles of repose of the two oat seed types at 33.19°, 33.82° and 22.45°, 23.57°; the static friction coefficient and rolling friction coefficient were the experimental factors, and the angle of repose was the experimental indicator in the simulation. The steepest climbing experiment determined the optimal range of the experimental factor, and the regression equation between the static friction coefficient, rolling friction coefficient and angle of repose was established by a quadratic orthogonal rotation combination experiment. Finally, the angles of repose measured by the bench experiment with the two different measurement methods were treated as target values, the coefficient of static friction and the coefficient of rolling friction were solved; the coefficient of static friction between hulless oats was 0.36, and the coefficient of rolling friction between hulless oats was 0.052; the coefficient of static friction between shelled oats was 0.24, and the coefficient of rolling friction between shelled oats was 0.036. The obtained contact parameters between seeds were input into EDEM, the simulation and bench experiment results were verified. The difference between the simulation results and the actual values was within 3%. The angle of repose of oats after calibration was close to the actual situation, and the calibration results had high reliability and provided a referencefor the measurement of contact parameters between other agricultural crop seeds. Keywords: Calibration, Contact parameters, Discrete element method, Oat.

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Dorn, Michael, Karolína Habrová, Radek Koubek, and Erik Serrano. "Determination of coefficients of friction for laminated veneer lumber on steel under high pressure loads." Friction 9, no. 2 (November 16, 2020): 367–79. http://dx.doi.org/10.1007/s40544-020-0377-0.

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AbstractIn this study, static coefficients of friction for laminated veneer lumber on steel surfaces were determined experimentally. The focus was on the frictional behaviors at different pressure levels, which were studied in combination with other influencing parameters: fiber orientation, moisture content, and surface roughness. Coefficients of friction were obtained as 0.10–0.30 for a smooth steel surface and as high as 0.80 for a rough steel surface. Pressure influenced the measured coefficients of friction, and lower normal pressures yielded higher coefficients. The influence of fiber angle was observed to be moderate, although clearly detectable, thereby resulting in a higher coefficient of friction when sliding perpendicular rather than parallel to the grain. Moist specimens contained higher coefficients of friction than oven-dry specimens. The results provide realistic values for practical applications, particularly for use as input parameters of numerical simulations where the role of friction is often wrongfully considered.

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Ducotey, K. S., and J. K. Good. "The Importance of Traction in Web Handling." Journal of Tribology 117, no. 4 (October 1, 1995): 679–84. http://dx.doi.org/10.1115/1.2831535.

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An experimental study shows that the traction coefficient of friction (μT) is a function of the predicted air film height, the roller and film surface roughness, and the static coefficient of friction between the web and roller. The traction coefficient shows a noticeable decrease as the air film height becomes greater than the equivalent root mean square roughness of the web and roller and also becomes less dependent on the static coefficient of friction.

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Pattan, Sadhiq Khan, Revathi Peddu, Shyam Kumar Bandaru, Devikanth Lanka, Kalyani Mallavarapu, and Azher Banu Pathan. "Efficacy of Super Slick Elastomeric Modules in reducing Friction during Sliding: A Comparative in vitro Study." Journal of Contemporary Dental Practice 15, no. 5 (2014): 543–51. http://dx.doi.org/10.5005/jp-journals-10024-1576.

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ABSTRACT Aim To evaluate and compare the frictional resistance produced by Super Slick modules during sliding with four different types of brackets and four ligature types both in conventional and figure-of-8 ligation method with saliva as lubricant. Materials and methods The frictional resistance was evaluated by using four different ligatures on 0.019” × 0.025” stainless steel (SS) archwires using four different brackets using an universal testing machine with unstimulated saliva as a lubricant. Mean and SD values were calculated. Data was statistically analyzed using analysis of variance ANOVA with post hoc test. Results The results showed that self-ligating brackets produced least frictional forces. Among all other tested combinations, Teflon-coated SS ligatures in ceramic with metal slot brackets produced least coefficient of static and kinetic friction and full ceramic brackets ligated with Super Slick elastomeric modules demonstrated the highest, with other combinations falling in between. Conclusion Super Slick elastomeric modules, produced highest coefficient of both static and kinetic friction with the conventional and figure-of-8 ligation technique even in wet conditions using natural fresh human saliva. Clinical significance Both static and kinetic frictional resistance play an important role during sliding mechanics. Various factors have been attributed for friction. However, bracket type, archwire material, type of ligature and method of ligation are important variables. Recently polymeric coated slick elastomeric modules were introduced with the claim that they produce very low frictional forces in wet condition. Contrary to the claim made by the manufacturers of Super Slick elastomeric modules, they produced highest coefficient of both static and kinetic friction with the conventional and figure-of-8 ligation technique. How to cite this article Pattan SK, Peddu R, Bandaru SK, Lanka D, Mallavarapu K, Pathan AB. Efficacy of Super Slick Elastomeric Modules in reducing Friction during Sliding: A Comparative in vitro Study. J Contemp Dent Pract. 2014; 15(5):543-551.

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Ohzono, T., and K. Teraoka. "Designing Load-Dependency of Static Friction of Elastomer Covered with Mesh Sheets." International Polymer Science and Technology 45, no. 1 (January 2018): 1–3. http://dx.doi.org/10.1177/0307174x1804500101.

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The static friction of compliant elastomers has proven important for industrial applications, including seals, and grips on tools and sports equipment. The design of load-dependent contact state may provide characteristic load-dependent frictional properties beyond that found on conventional rubber surfaces. Here we investigate the static friction, over a wide range of normal loads, between a fat glass surface and polyester meshes adhered on an elastomer surface. At low load the glass is supported only by the mesh members and the static friction is low. As normal load increases, the mesh members tend to dent into the elastomer and at the pore of the mesh the elastomer surface may make contact with the glass. The newly created contact with the elastomer makes the static friction increase with the higher friction coefficient. By tuning the structures, e.g., the aperture ratio, of meshes, we can extend the monotonic load-dependency of static friction of rubbers into the highly nonlinear range.

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Molina-Bolívar, J. A., and M. A. Cabrerizo-Vílchez. "Determination of the static friction coefficient from circular motion." Physics Education 49, no. 4 (July 2014): 400–405. http://dx.doi.org/10.1088/0031-9120/49/4/400.

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MAEGAWA, Satoru, Fumihiro ITOIGAWA, Takatoshi SHINYOSHI, Atsushi SUZUKI, Chiharu TADOKORO, and Ken NAKANO. "Design Criteria on Effective Static Friction Coefficient of Elastomers." TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C 79, no. 803 (2013): 2622–34. http://dx.doi.org/10.1299/kikaic.79.2622.

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Olvera-Tapia, Omar, Ernst Kussul, José M. Rodríguez-Lelis, Tatiana Baidyk, and José Sanchez. "Effect of Bushing Miniaturization on the Static Friction Coefficient." Journal of Testing and Evaluation 44, no. 4 (February 10, 2015): 20140284. http://dx.doi.org/10.1520/jte20140284.

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Li, Pan-Pan, Feng Gao, Yan Li, and Bo Yang. "Study on friction characteristics of sliding interface of feed system." Industrial Lubrication and Tribology 72, no. 7 (April 4, 2020): 865–71. http://dx.doi.org/10.1108/ilt-11-2019-0482.

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Purpose The serious friction caused by the fluctuation of friction occurs when start-up and will reduce the positioning accuracy of the servo axes of high precision machine tools, the purpose of this paper is to study the friction fluctuation characteristics of friction coefficients between interfaces under different working conditions. Design/methodology/approach HT200 and 45# materials were experimentally studied by friction and wear testing machine UMT-3, the variation of friction coefficient under different working conditions (different start-up conditions, the variation of lubrication state area and different roughness) were measured. Findings The results show that the larger start-up acceleration shortens the pre-sliding time of the interface friction, makes the friction coefficient decrease faster, reduces the mixed lubrication area of the contact surface and makes the contact surface reach the stable lubrication state quickly. It can be concluded that the larger roughness surface will lead to the larger mixed lubrication area, the larger static friction coefficient and the larger drop between static and dynamic friction coefficient and easy to cause friction vibration. Originality/value The results reveal the friction fluctuation rule of the metal interface during the different start-up process, which is of guiding significance to reveal the lubrication principle and mechanism of the mechanical interface. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2019-0482/

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Ma, Xue Feng, Dong Hua Guo, and Yu Hong Lu. "The Research of Static Friction Coefficient Measure Technology and Calibration Method for Traffic Engineering." Applied Mechanics and Materials 128-129 (October 2011): 1493–96. http://dx.doi.org/10.4028/www.scientific.net/amm.128-129.1493.

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The measure technology of static friction coefficient of traffic engineering communication and cable ducts by using inclined plane method is introduced in this paper. The calibrated method for that equipment system of static friction coefficient is discussed, furthermore.

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Kogut, Lior, and Izhak Etsion. "A Static Friction Model for Elastic-Plastic Contacting Rough Surfaces." Journal of Tribology 126, no. 1 (January 1, 2004): 34–40. http://dx.doi.org/10.1115/1.1609488.

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A model that predicts the static friction for elastic-plastic contact of rough surfaces is presented. The model incorporates the results of accurate finite element analyses for the elastic-plastic contact, adhesion and sliding inception of a single asperity in a statistical representation of surface roughness. The model shows strong effect of the external force and nominal contact area on the static friction coefficient in contrast to the classical laws of friction. It also shows that the main dimensionless parameters affecting the static friction coefficient are the plasticity index and adhesion parameter. The effect of adhesion on the static friction is discussed and found to be negligible at plasticity index values larger than 2. It is shown that the classical laws of friction are a limiting case of the present more general solution and are adequate only for high plasticity index and negligible adhesion. Some potential limitations of the present model are also discussed pointing to possible improvements. A comparison of the present results with those obtained from an approximate CEB friction model shows substantial differences, with the latter severely underestimating the static friction coefficient.

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Li, Qin Liang, Bin Zhao, Bo Wang, and Bang Chun Wen. "Discrete Element Analysis of Friction Coefficient on Granular Accumulation." Advanced Engineering Forum 2-3 (December 2011): 894–99. http://dx.doi.org/10.4028/www.scientific.net/aef.2-3.894.

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Discrete element method (DEM) is applied to study the granular accumulation problem. Using Herz-Mindlin (no slip) model to simulate particles and container model is also established by software. When the container elevates, the process of granular falling and collision can be ob-served. Detailed analysis of that the impact of static and rolling friction coefficient for particles - particles, particles - flat on angle of repose is accomplished. The variation law is also further val-idated from the energy point of view. The results show that rolling friction has a greater impact on angle of repose than static friction, and rolling friction coefficient among particles play the more prominent role in the two kinds of rolling friction. The research method and results provide a the-oretical reference for the granular movement and DEM analysis.

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Shah, Rajesh C., and Rajiv B. Shah. "Static and dynamic performances of ferrofluid lubricated long journal bearing." Zeitschrift für Naturforschung A 76, no. 6 (May 14, 2021): 493–506. http://dx.doi.org/10.1515/zna-2021-0057.

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Abstract Due to the advantageous property of reduction of load friction, low wear and good damping characteristics, journal bearings are widely used in industry. They are equipping various rotating machineries like small electrical motors to large generators, internal combustion engines, centrifugal pumps, turbine shaft of most jet engines, crankshaft of an automobile engines, etc. In this paper, static and dynamic performances of ferrofluid (FF) lubricated long journal bearing are studied using rotational and translational approach of the journal. Here, FF is controlled by the transverse uniform magnetic field. The modified Reynolds equation is derived by considering FF flow behaviour given by Shliomis and continuity equation in the film region. The dimensionless expressions for load-carrying capacity, frictional force and coefficient of friction are studied for static case, while the dimensionless expressions for stiffness coefficients and damping coefficients are studied for dynamic case. It is observed that comparing with conventional lubricant the bearing performance is significantly modified in the present analysis.

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Dickson, J. A. S., S. P. Jones, and E. H. Davies. "A Comparison of the Frictional Characteristics of Five Initial Alignment Wires and Stainless Steel Brackets at Three Bracket to Wire Angulations—an in Vitro Study." British Journal of Orthodontics 21, no. 1 (February 1994): 15–22. http://dx.doi.org/10.1179/bjo.21.1.15.

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The study investigated static planar frictional resistance between five initial alignment wires and stainless steel brackets at three brackets to wire angulations (0, 5 and 10 degrees). It was demonstrated that static frictional resistance increased significantly with increasing bracket to wire angulation due to binding within the system. Epoxy-coated steel had the highest static frictional resistance and coaxial stainless steel the lowest. Fibre-optic glass (Optiflex®) had low frictional resistance. The coefficient of friction followed the trends of static frictional resistance in all respects.

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Lee, Chul-Hee, and Andreas A. Polycarpou. "Static Friction Experiments and Verification of an Improved Elastic-Plastic Model Including Roughness Effects." Journal of Tribology 129, no. 4 (April 17, 2007): 754–60. http://dx.doi.org/10.1115/1.2768074.

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An experimental study was conducted to measure the static friction coefficient under constant normal load and different interface conditions. These include surface roughness, dwell time, displacement rate, as well as the presence of traces of lubricant and wear debris at the interface. The static friction apparatus includes accurate measurement of friction, normal and lateral forces at the interface (using a high dynamic bandwidth piezoelectric force transducer), as well as precise motion control and measurement of the sliding mass. The experimental results show that dry surfaces are more dependent on the displacement rate prior to sliding inception compared to boundary lubricated surfaces in terms of static friction coefficient. Also, the presence of wear debris, boundary lubrication, and rougher surfaces decrease the static friction coefficient significantly compared to dry smooth surfaces. The experimental measurements under dry unlubricated conditions were subsequently compared to an improved elastic-plastic static friction model, and it was found that the model captures the experimental measurements of dry surfaces well in terms of the surface roughness.

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Liu, Zhiqiang, Anne Neville, and R. L. Reuben. "The Effect of Film Thickness on Initial Friction of Elastic-Plastically Rough Surface With a Soft Thin Metallic Film." Journal of Tribology 124, no. 3 (May 31, 2002): 627–36. http://dx.doi.org/10.1115/1.1454103.

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The effect of a deposited soft thin metallic film on friction properties of a hardened steel substrate has been investigated experimentally and theoretically. The dependency of the film thickness and contact load on the static friction coefficient is presented. The experimental observations show that deformation of the film in contact was plastic, thereby confirming the assumption of the theoretical calculation. The effect of the film thickness on the contact area has been analyzed. A model for calculating the static friction coefficient of contacting rough surfaces in the presence of a soft thin film has been used. Results from the numerical calculations have been compared with the present static friction measurements performed on a pin on plate reciprocating apparatus. The rise in friction that occurs with increasing thickness for very thin films is discussed in detail. The calculated results, which predict the correct trend of the friction behavior from the present experiment, cover an extremely large range of F/AnE from 10−12 to 10−2, where three different dependencies of F/AnE on the static friction coefficient can be identified. An investigation into the discrepancy between the calculated and experimental values for the static friction coefficient μ suggests that an accurate prediction of the magnitude of μ depends to a great extent on the level of accuracy in measuring the value of the constant ζ, the effective hardness of the film.

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Adams, G. G. "Steady Sliding of Two Elastic Half-Spaces With Friction Reduction due to Interface Stick-Slip." Journal of Applied Mechanics 65, no. 2 (June 1, 1998): 470–75. http://dx.doi.org/10.1115/1.2789077.

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The sliding of two perfectly flat elastic half-spaces with a constant interfacial coefficient of friction is investigated. Previous work has demonstrated that this configuration is dynamically unstable due to the destabilization of frictional slip waves. It was speculated that this dynamic instability could lead to stick-slip motion at the sliding interface. It is shown here that stick-slip motion at the interface can exist with a speed-independent interface coefficient of friction. Steady motion persists sufficiently far from the interface and thus gives the impression of uniform sliding. This type of stick-slip motion is due to interfacial slip waves and allows the bodies to slide with an apparent coefficient of friction which is less than the interface coefficient of friction. Furthermore it is shown that the apparent friction coefficient decreases with increasing speed even if the interface friction coefficient is speed-independent. Finally, it is shown that the presence of slip waves may make it possible for two frictional bodies to slide without a resisting shear stress and without any interface separation. No distinction is made between static and kinetic friction.

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Wu, Jian, Hang Luo, Haohao Li, Benlong Su, Youshan Wang, and Zhe Li. "The Influence of Hydrothermal Aging on the Dynamic Friction Model of Rubber Seals." Polymers 12, no. 1 (January 4, 2020): 102. http://dx.doi.org/10.3390/polym12010102.

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Cylinder has become an indispensable and important pneumatic actuator in the development of green production technology. The sealing performance of the cylinder directly affects its safety and reliability. Under the service environment of the cylinder, hydrothermal aging of the rubber sealing ring directly affects the dynamic friction performance of the cylinder. So, the dynamic friction model of the cylinder has been developed based on the LuGre friction model, which considers the influence of hydrothermal aging. Here, the influences of the static friction coefficient and Coulomb friction coefficient on the friction model are analyzed. Then, the aging characteristic equation of rubber is embedded in the model for revealing the influence of aging on the friction coefficient of the model. Results show that the aging temperature, aging time, and compressive stress affects the friction coefficient; the variation of the static friction coefficient is larger than that of the Coulomb friction coefficient. The improved cylinder friction model can describe the influence of the aging process on the cylinder friction characteristics, which is of great significance in the design of the cylinder’s dynamic performance.

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Yu,, Ning, Shaun R. Pergande, and, and Andreas A. Polycarpou. "Static Friction Model for Rough Surfaces With Asymmetric Distribution of Asperity Heights." Journal of Tribology 126, no. 3 (June 28, 2004): 626–29. http://dx.doi.org/10.1115/1.1739406.

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The CEB static friction model is extended to include asymmetric distributions of asperity heights, using the normalized one-parameter Weibull distribution. The normal contact, tangential (friction), and adhesion forces are calculated for different skewness values, and are used to obtain the static friction coefficient. It is predicted that surfaces with negative skewness experience higher static friction coefficient compared to the Gaussian case, under the same external normal load, which agrees with published data. This effect is magnified for lower external loads, as is commonly encountered in microtribological applications.

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Liu, Zhiqiang, Anne Neville, and R. L. Reuben. "Static Friction Modeling in the Presence of Soft Thin Metallic Films." Journal of Tribology 124, no. 1 (January 31, 2001): 27–35. http://dx.doi.org/10.1115/1.1395628.

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A numerical model is presented for computing the static friction coefficient of rough surfaces with a soft thin film. In the calculation, an improved model, based on that due to Derjaguin et al., is used in conjunction with an elastic-plastic contact model for contact with a soft coating. The effects of the film thickness and surface roughness on the static friction coefficient and contact are investigated. The numerical results reflect published experimental observations and show the static friction coefficient depends strongly on surface film thickness, external force and surface roughness. The static friction coefficient (μ) increases with the surface film thickness when the plasticity index ψ⩾0.5 whilst μ increases with decreasing film thickness in the very thin film regime when ψ=0.25 and F/AnE<10−4. For real rough surfaces, contact and friction behavior is probably heavily influenced by the existence of such soft, thin surface films, which increase the contact area due to plastic deformation of the film and the contact stiffness of the surface in the case of thin film and light load.

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WIELEBA, Wojciech, and Mariusz OPAŁKA. "STATIC FRICTION OF REVERSE STEEL–ELASTOMER SLIDING PAIRS." Tribologia 279, no. 3 (July 1, 2018): 147–51. http://dx.doi.org/10.5604/01.3001.0012.7023.

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Sliding cooperation of materials with different hardness (deformability), e.g., a polymeric material cooperating with metallic materials, occurs in machine elements in one of the following two variants: a conventional pair or a reverse pair. In the case of the conventional sliding pair, the deformation area (contact area) of the sliding materials does not move on the surface of the polymer element during their cooperation. In the case of reverse pairs, the contact surface changes its position when moving on the surface of the polymer element. Depending on the variant of the sliding pair, the differences in the friction and wear process of polymer material can be observed. Tribological investigations of chosen sliding pairs (elastomer on steel or steel on elastomer) in the static friction were carried out on the rig. The polymeric materials selected for the tests were thermoplastic elastomers TPU, PUR, and silicone rubber SI. These materials co-operated with C45 steel in the different contact pressures (p = 0.1 – 0.26 MPa) under dry friction or mixed lubrication conditions (hydraulic oil Hipol HLP-68). Based on the recorded value of the friction force Ft, the values of static coefficients of friction μstat were determined. The test results showed a significant influence of the variant of the combination of materials (metal-polymer or polymer-metal) on the value of the friction coefficient. In all tested pairs in which steel sample (pin) slid against elastomeric plates, the friction coefficient was higher than in the case when the elastomeric sample (pins) cooperated with steel counterfaces (plates). The main reason is the considerable value of the deformation component of the friction force. This is probably due to the displacement of the elastomer deformation area in its surface layer and energy dissipation as a result of stress-strain hysteresis in the elastomeric material, as in the case with reversed pairs.

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ECK, C., and J. JARUSEK. "EXISTENCE RESULTS FOR THE STATIC CONTACT PROBLEM WITH COULOMB FRICTION." Mathematical Models and Methods in Applied Sciences 08, no. 03 (May 1998): 445–68. http://dx.doi.org/10.1142/s0218202598000196.

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We prove the existence of solutions to the static contact problem with Coulomb friction, provided that the coefficient of friction is small enough. The proof employs the penalty method and a certain smoothing procedure for the friction functional. Using optimal trace estimates for the solutions of the Lamé equations, we calculate an upper bound for the admissible coefficient of friction which is greater than the corresponding bounds proposed by Necas, Jarusek and Haslinger (1980) and by Jarusek (1983).

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Hu, Yu Mei, De Shuang Xue, and Yang Jun Pi. "Effect of Friction Coefficient on the Stiffness Excitation of Gear." Applied Mechanics and Materials 86 (August 2011): 713–16. http://dx.doi.org/10.4028/www.scientific.net/amm.86.713.

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This study addresses the effect of different friction coefficients on the stiffness excitation of gear using finite element technique. Firstly, the simulation model of single pair of gear teeth mesh is established, and the effect of friction coefficient on the composite stiffness values of the teeth meshing is studied. After that, simulation model of multiple pairs of gear teeth meshing is created and the normal load distributions under different friction coefficients in a single meshing cycle are calculated using quasi-static calculation method. Finally, the relationship between friction coefficient and stiffness excitation of gear system is obtained. The investigation results indicate that at the alternation place of single tooth meshing and double teeth meshing, the stiffness excitation of the system is greater under larger friction coefficient when double teeth meshing change into single tooth meshing, while the opposite situation occur when single tooth meshing change into double teeth meshing. The amplitude value of stiffness variation for single pair of teeth meshing under different friction coefficients is 2.12%, while the amplitude value of teeth loads variation for multiple pairs of teeth meshing under different friction coefficients is 22.87%.

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BIERNACKI, Krzysztof. "ESTIMATION OF THE COEFFICIENT OF STATIC FRICTION BY MEANS OF NUMERICAL ANALYSIS." Tribologia 287, no. 5 (October 31, 2019): 19–24. http://dx.doi.org/10.5604/01.3001.0013.6557.

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The friction coefficient is one of the most important tribological parameters. The value of this coefficient may be determined with the use of various methods. The friction coefficient proves to be of significance when assembling the elements of the gear pump body WPZ-80A. The bodies of these pumps consist of three elements and are manufactured in two configurations of materials. These materials are aluminium alloy AK-20 and grey iron ZL-250. Friction interaction between the elements of the pump body ensures its stable operation under load. Research so far has focused on numerical analyses for pump bodies at a set friction coefficient. This article presents a reverse analysis, i.e. an estimation of the friction coefficient value based on the WPZ-80A pump body effort. To this end, numerical analysis based on the Finite Element Method (FEM) has been used. The analysis was based on the fact that the value of friction coefficient significantly influences deformation distribution in the WPZ-80A pump body. The analysis was performed on an already constructed pump body of known geometry with no structural modifications. The value of the static friction coefficient was estimated by observing the scale of deformations in the pump body under a set load. Although the main focus was on analysing the mechanism behind the deformations, an attempt was also made at extending the application scope for FEM. Depending on the measurement method, friction coefficient values may significantly differ. Despite the differences, the values resulting from numerical analysis should not differ from the range of values obtained with other methods of analysis. The range of friction coefficient values was determined on the basis of literature studies. As a result, it was possible to verify FEM in a field different than classic effort analysis. The aim of the work presented in this article was to obtain information on tribological properties with the use of numerical analysis.

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Gerber, C. T., B. Bhushan, and N. V. Gitis. "Experimental Study of Long-Term Static Friction and Magnetic Slider/Disk Interplanar Separation." Journal of Tribology 118, no. 1 (January 1, 1996): 12–20. http://dx.doi.org/10.1115/1.2837067.

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Capacitance between a slider and disk was measured to relate slider/disk interplanar separation to static friction. The parallel plate capacitance formula was used to convert the capacitance into separation with a resolution of less than 1 nm. Separation and coefficient of static friction (stiction) were measured using assorted lubricant thicknesses with and without bonding on polished and textured disks. Separation was measured during contact start/stop (CSS) and long term slider dwell times, after which static friction was measured. Polished disks had high stiction events with smaller separations during and after the stiction event, unlike textured disks. Long-term dwell studies showed the coefficient of static friction and slider micro descent (decrease in interplanar separation) to be greatest with greater lubricant thickness and polished disks. Static friction and separation with bonded and unlubricated disks were time independent.

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NIEMIEC, Aneta. "THE ANALYSIS OF THE INFLUENCE OF GAMMA IRRIADIATED POLYSULFONES ON THE STATIC FRICTION COEFFICIENT." Tribologia, no. 4 (August 31, 2017): 65–70. http://dx.doi.org/10.5604/01.3001.0010.5995.

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The paper presents the results of studies on the effects of gamma irradiation on the static friction coefficient of thermoplastic polymer – polysulfone. These polar polymers belong to the group of amorphous thermoplastics and are widely used for various applications, e.g., automotive and electronic industries (dielectrics in capacitors), waste water recovery, medical uses (hemodialysis membranes), requiring autoclave, and steam sterilization. Polysufones are known for their toughness and stability at high temperatures. The aim of this study is to analysed changes in the static coefficient of friction in association with a contact pressure (in the range 0.2 – 0.8 MPa) depending on the ionizing radiation dose of PSU (in the range 50-150 kGy). Additionally, microhardness, and wear intensity were measured, because tribological properties of polymers as well as mechanical properties that influence their durability and applications. The studies confirmed that the static coefficient of friction increases with an increase in contact pressure (in the test range). The research has shown that mechanical (microhardness) and tribological (static coefficient of friction and tribological wear) improve as the radiation dose of irradiated material increase. Moreover, the tribological wear increases with increasing the sliding velocity. This gamma irradiated polymer is characterized by higher microhardness, a static coefficient of friction, and a higher wear rate compared to PSU in the initial state, because of changes in structure. It requires further research.

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Chen, Zhengpu, Carl Wassgren, and Kingsly Ambrose. "Measurements of Grain Kernel Friction Coefficients Using a Reciprocating-Pin Tribometer." Transactions of the ASABE 63, no. 3 (2020): 675–85. http://dx.doi.org/10.13031/trans.13748.

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Highlights A tribometer was used to measure the friction coefficients of corn and wheat kernels. Both static and dynamic friction coefficients were measured for particle-wall interaction. Data analysis processes were developed to calculate dynamic friction coefficients for inter-particle interaction. Abstract. Various devices have been developed to measure the coefficient of friction (COF) of grain kernels; however, the majority of these tests measure the particle-wall COF at a bulk level. A method that can accurately measure both particle-wall and inter-particle COFs at a single-particle level remains to be developed. The objective of this study was to explore the feasibility of using a reciprocating-pin tribometer to measure static and dynamic COFs between grain kernels and between grain kernels and wall materials. In this study, the methodology of the test was developed, and representative data from the particle-wall and inter-particle friction tests were reported. It was found that the static COFs of corn-steel, corn-acrylic, wheat-steel, and wheat-acrylic are 0.24 ±0.05, 0.22 ±0.03, 0.32 ±0.02, and 0.29 ±0.03, respectively. The dynamic COFs of corn-steel, corn-acrylic, corn-corn, wheat-steel, wheat-acrylic, and wheat-wheat are 0.22 ±0.06, 0.16 ±0.01, 0.09 ±0.02, 0.30 ±0.02, 0.20 ±0.02, and 0.18 ±0.04, respectively. The current study demonstrates that the reciprocating-pin tribometer is suitable for measuring the particle-wall and inter-particle COFs of grain kernels. Keywords: Coefficient of friction, Grain kernel, Reciprocating-pin tribometer

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Jourani, Abdeljalil. "Effect of Asperity Interactions and Mesh Resolution on Friction Coefficient." International Journal of Applied Mechanics 08, no. 08 (December 2016): 1650090. http://dx.doi.org/10.1142/s1758825116500903.

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Few models are devoted to explain the effect of surface roughness on the friction coefficient. Most of them use statistical approaches and do not incorporate the transition from elastic deformation to fully plastic flow. In this paper, a three-dimensional (3D) deterministic model is developed by considering different deformation modes of surface roughness which range from fully elastic through elastic–plastic to fully plastic contact interface. The simulations show that the increase in the surface roughness and mesh resolution lead to the increase in the static friction coefficient. For surfaces which present a low roughness, the static friction coefficient increases with increase in the normal load. The transition from elastic to plastic deformation is responsible for the increase of the friction coefficient with normal load. The comparison between experimental and numerical results reveals that the experimental friction coefficient is slightly larger than the calculated one. This difference does not exceed 10%. The multiscale roughness and the simplified geometry used to describe the shape of the surface roughness can explain the gap between experimental and numerical results in terms of friction coefficient.

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Wang, Qian Qian, Geng Chen Shi, and Xin Xiong. "Static Friction Research of LIGA-Microstructure: Comparison between Theory and Experiments." Advanced Materials Research 301-303 (July 2011): 1109–14. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.1109.

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Micro electro mechanical system (MEMS) has been increasingly used in military application. For the reliability and specialty of military requirements, the material of the MEMS device is supposed to be metal and the device is moveable. Lithographic, Galvanoforming, Abformung (LIGA) technology capable of producing high aspect ratio structures in metals like nickel is one of the important fabrication technologies in military MEMS. There are many moveable MEMS device like micro-gear and micro-slider producing by LIGA technology. But the moveable devices cannot behave well because of the friction effect. In this paper, an improved elastic-plastic model including roughness effects and an experimental procedure that predict the static friction prosperity of LIGA-processed nickel is proposed. Firstly, we use the 3D optical profilometer to research the surface roughness of LIGA-processed nickel, the surface heights distribution was found to be nearly Gaussian distribution. Secondly, the static friction model, the Kogut-Etsion (KE) model is adopted to obtain the static friction coefficient. Finally, a special designed static friction coefficient measurement apparatus is used to conduct the friction experiments. The results indicate that the surface roughness affects the friction and the smoother surface leads to a higher friction coefficient. Also good agreement was found between simulations and experimental results.

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Altuntaş, Ebubekir. "The Volumetrical, Geometrical and Frictional Properties of White Mulberry (Morus alba L.) Fruits." Turkish Journal of Agriculture - Food Science and Technology 4, no. 11 (November 16, 2016): 987. http://dx.doi.org/10.24925/turjaf.v4i11.987-990.932.

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The volumetrical, geometrical and frictional properties of white mulberry fruits (Morus alba L.) determined at a moisture content of 13.89% (d.b.). The mean values of the fruit mass, porosity, fruit volume, fruit and bulk densities values of white mulberry fruits were found as 1.06 g, 75.3%, 0.53 cm3, 1911.7 kg/m3 and 454.0 kg/m3, respectively. The mean values of the surface area, sphericity and geometric mean diameter and were 4.16 cm2, 71.02% and 11.5 mm, respectively. The angle of repose of the white mulberry fruits was found as 22.1 and also, the mean values of dynamic and static coefficient of friction against plywood, chipboard, galvanized steel, rubber and mild steel surfaces were determined and the highest dynamic and static coefficients of friction values of white mulberry fruits were found for rubber surface.

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Amassad, A., K. L. Kuttler, M. Rochdi, and M. Shillor. "Quasi-static thermoviscoelastic contact problem with slip dependent friction coefficient." Mathematical and Computer Modelling 36, no. 7-8 (November 2002): 839–54. http://dx.doi.org/10.1016/s0895-7177(02)00231-5.

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DeBusk, Hunter, Levi Dixon, Joellen Gill, and Richard Gill. "Measuring the Static Coefficient of Friction of Non-Fluid Contaminants." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 63, no. 1 (November 2019): 537–41. http://dx.doi.org/10.1177/1071181319631385.

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The purpose of our study was to evaluate whether there are differences between measuring the static coefficient of friction (SCOF) of a non-fluid contaminant when it is directly attached to a tribometer test foot, or “Attached”, versus when it is lying loose on the floor, or “Loose”. The non-fluid materials used in this study included Mylar, Cardboard, Terrycloth Bathmat, and Terrycloth Bathmat with Rubberized Silicon Backing; the floor material was porcelain tile. In addition, 10 participants subjectively rated the “slipperiness” of each material by pushing the materials with one foot across the porcelain tile. The findings of this study revealed that within each technique, Attached and Loose, the measurements were consistent and reliable. Furthermore, both techniques resulted in identical ordering of the materials from lowest to highest SCOF, which was verified by the human subjects’ subjective ratings of slipperiness. However, the Loose technique SCOF values were slightly but consistently greater than the Attached technique SCOF values; the Loose tests of the entire bathmats were found to have greater SCOF values when compared to Loose tests of small samples. These findings suggest that when investigating a specific slip event, a practitioner should measure the SCOF of the non-fluid contaminant using the technique which most closely represents the conditions of the slip event.

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Journal articles on the topic 'Coefficient of static friction'

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