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Belyakov, N. & Nosko, O. (2016). Analytical solution of non-stationary heat conduction problem for two sliding layers with time-dependent friction conditions. International Journal of Heat and Mass Transfer, 98, 624-630
Open this publication in new window or tab >>Analytical solution of non-stationary heat conduction problem for two sliding layers with time-dependent friction conditions
2016 (English)In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 98, p. 624-630Article in journal (Refereed) Published
Abstract [en]

In this article we conduct an overview of various types of thermal contact conditions at the sliding interface. We formulate a problem of non-stationary heat conduction in two sliding layers with generalized thermal contact conditions allowing for dependence of the heat-generation coefficient and contact heat transfer coefficient on time. We then derive an analytical solution of the problem by constructing a special coordinate integral transform. In contrast to the commonly used transforms, e.g. Laplace or Fourier transforms, the one proposed is applicable to a product of two functions dependent on time. The solution is validated by a series of test problems with parameters corresponding to those of real tribosystems. Analysis shows an essential influence of both time-dependent heat-generation coefficient and contact heat transfer coefficient on the partition of the friction heat between the layers. The solution can be used for simulating temperature fields in sliding components with account of this influence.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Non-stationary heat conduction, Sliding layers, Imperfect thermal contact, Integral transform
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-186240 (URN)10.1016/j.ijheatmasstransfer.2016.03.054 (DOI)000375360600059 ()2-s2.0-84962010419 (Scopus ID)
Note

QC 20160512

Available from: 2016-05-07 Created: 2016-05-07 Last updated: 2018-01-10Bibliographically approved
Nosko, O. (2016). Analytical Study of Sliding Instability due to Velocity- and Temperature-Dependent Friction. Tribology letters, 61(2), 1-10
Open this publication in new window or tab >>Analytical Study of Sliding Instability due to Velocity- and Temperature-Dependent Friction
2016 (English)In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 61, no 2, p. 1-10Article in journal (Refereed) Published
Abstract [en]

The instability of sliding causes deterioration of performance characteristics of tribosystems and is undesired. To predict its occurrence, the motion of a body of a one-degree-of-freedom system with friction is investigated about the steady sliding equilibrium position. The motion equation is formulated with the friction coefficient dependent on the sliding velocity and contact temperature changing due to transient heat conduction in the body. An analytical expression for the body motion is derived using the Laplace integral transform. It is shown that the sliding instability can manifest in the form of deviation of the body from the equilibrium position or in the form of oscillation. The instability conditions containing the friction–velocity and friction–temperature slope coefficients are obtained. Positive friction–temperature slope results in the deviation of the body from the equilibrium position. At negative friction–temperature slope, both types of the sliding instability can occur. The proposed instability conditions agree well with existing theoretical concepts and can be useful when designing tribosystems.

Place, publisher, year, edition, pages
Springer-Verlag New York, 2016
Keywords
Sliding instability, Frictional oscillation, Frictional heating, Instability condition
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-180529 (URN)10.1007/s11249-015-0628-9 (DOI)000368597500001 ()2-s2.0-84949292577 (Scopus ID)
Note

QC 20160121. QC 20160220

Available from: 2016-01-14 Created: 2016-01-14 Last updated: 2018-01-10Bibliographically approved
Alemani, M., Nosko, O., Metinoz, I. & Olofsson, U. (2015). A Study on Emission of Airborne Wear Particles from Car Brake Friction Pairs. Paper presented at SAE Brake Colloquium 2015. SAE International Journal of Materials and Manufacturing, 9(1), 147-157
Open this publication in new window or tab >>A Study on Emission of Airborne Wear Particles from Car Brake Friction Pairs
2015 (English)In: SAE International Journal of Materials and Manufacturing, ISSN 1946-3979, Vol. 9, no 1, p. 11p. 147-157Article in journal (Other academic) Published
Abstract [en]

The emission of airborne wear particles from friction material / cast iron pairs used in car brakes was investigated, paying special attention to the influence of temperature. Five low-metallic materials and one non-asbestos organic material were tested using a pin-on-disc machine. The machine was placed in a sealed chamber to allow airborne particle collection. The concentration and size distribution of 0.0056 to 10 μm particles were obtained by a fast mobility particle sizer and an optical particle sizer. The temperature was measured by a thermocouple installed in the disc. The experiments show that as the temperature increases from 100 to 300 °C the emission of ultrafine particles intensifies while that of coarse particles decreases. There is a critical temperature at which the ultrafine particle emission rate rises stepwise by 4 to 6 orders of magnitude. For the friction pairs investigated, the critical temperature was found to be between 165 and 190 °C. Below the critical temperature, fine particles outnumber coarse and ultrafine particles, although coarse particles make up the bulk of the particulate matter mass. The friction pairs differ in the ultrafine particle emission rate by 1 to 2 orders of magnitude. Above the critical temperature, ultrafine particles constitute almost 100% of the total particle number and their relative mass contribution can exceed 50%. Analysis of the particle size distributions revealed peaks at 0.19-0.29, 0.9 and 1.7 μm. Above the critical temperature, one more peak appears in the ultrafine particle range at 0.011-0.034 μm.

Place, publisher, year, edition, pages
SAE International, 2015. p. 11
National Category
Engineering and Technology
Research subject
Machine Design
Identifiers
urn:nbn:se:kth:diva-208687 (URN)10.4271/2015-01-2665 (DOI)000386445700018 ()2-s2.0-84975807242 (Scopus ID)
Conference
SAE Brake Colloquium 2015
Projects
REBRAKE - G.A. 324385
Note

QC 20170613

Available from: 2017-06-11 Created: 2017-06-11 Last updated: 2017-06-13Bibliographically approved
Alemani, M., Nosko, O., Metinoz, I. & Olofsson, U. (2015). A study on emission of airborne wear particles from car brake friction pairs. SAE International Journal of Materials & Manufacturing, 9(1), 147-157, Article ID 2015-01-2665.
Open this publication in new window or tab >>A study on emission of airborne wear particles from car brake friction pairs
2015 (English)In: SAE International Journal of Materials & Manufacturing, ISSN 1946-3979, E-ISSN 1946-3987, Vol. 9, no 1, p. 147-157, article id 2015-01-2665Article in journal (Refereed) Published
Abstract [en]

The emission of airborne wear particles from friction material / cast iron pairs used in car brakes was investigated, paying special attention to the influence of temperature. Five low-metallic materials and one non-asbestos organic material were tested using a pin-on-disc machine. The machine was placed in a sealed chamber to allow airborne particle collection. The concentration and size distribution of 0.0056 to 10 μm particles were obtained by a fast mobility particle sizer and an optical particle sizer. The temperature was measured by a thermocouple installed in the disc. The experiments show that as the temperature increases from 100 to 300 °C the emission of ultrafine particles intensifies while that of coarse particles decreases. There is a critical temperature at which the ultrafine particle emission rate rises stepwise by 4 to 6 orders of magnitude. For the friction pairs investigated, the critical temperature was found to be between 165 and 190 °C. Below the critical temperature, fine particles outnumber coarse and ultrafine particles, although coarse particles make up the bulk of the particulate matter mass. The friction pairs differ in the ultrafine particle emission rate by 1 to 2 orders of magnitude. Above the critical temperature, ultrafine particles constitute almost 100% of the total particle number and their relative mass contribution can exceed 50%. Analysis of the particle size distributions revealed peaks at 0.19-0.29, 0.9 and 1.7 μm. Above the critical temperature, one more peak appears in the ultrafine particle range at 0.011-0.034 μm.

National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-169695 (URN)10.4271/2015-01-2665 (DOI)000386445700018 ()2-s2.0-84975807242 (Scopus ID)
Projects
Rebrake
Funder
EU, FP7, Seventh Framework Programme, 324385
Note

QC 20160211

Available from: 2015-06-22 Created: 2015-06-22 Last updated: 2018-01-11Bibliographically approved
Nosko, O., Nagamine, T., Mori, H. & Sato, Y. (2015). Friction-induced oscillations of a non-asbestos organic pin sliding on a steel disc. Acta Mechanica et Automatica, 9(2), 84-88
Open this publication in new window or tab >>Friction-induced oscillations of a non-asbestos organic pin sliding on a steel disc
2015 (English)In: Acta Mechanica et Automatica, ISSN 1898-4088, Vol. 9, no 2, p. 84-88Article in journal (Refereed) Published
Abstract [en]

Friction-induced oscillations result in deterioration of performance of disc brakes and are generally undesired. We conduct experimental study of friction-induced oscillations in a non-asbestos organic material/steel pair used in disc brakes of motor vehicles. The tests are done by use of a pin-on-disc machine in which the pin sample is supported on a deformable beam. The adjustable friction parameters are the disc velocity, contact pressure and temperature. The tests show that the friction coefficient decreases with the sliding velocity and increases with the temperature. The friction-induced tangential oscillation of the pin sample occurs with a frequency equal to the first natural frequency of the beam. The effects of the disc velocity and temperature on the oscillation characteristics are investigated. The oscillation amplitude increases with the disc velocity on the interval of velocities below 2 m/s. Temperature changes of several tens of degrees Celsius lead to the oscillation occurrence/decay. The obtained results can be useful for prognostication of friction-induced oscillations in disc brakes with non-asbestos organic pads.

Keywords
Friction-Induced Oscillation, Non-Asbestos Organic Material, Pin-On-Disc Machine, Sliding velocity, Temperature
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-173546 (URN)10.1515/ama-2015-0014 (DOI)2-s2.0-84937896088 (Scopus ID)
Note

QC 20150914

Available from: 2015-09-14 Created: 2015-09-14 Last updated: 2018-01-11Bibliographically approved
Nosko, O., Nagamine, T., Nosko, A. L., Romashko, A. M., Mori, H. & Sato, Y. (2015). Measurement of temperature at sliding polymer surface by grindable thermocouples. Tribology International, 88, 100-106
Open this publication in new window or tab >>Measurement of temperature at sliding polymer surface by grindable thermocouples
Show others...
2015 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 88, p. 100-106Article in journal (Refereed) Published
Abstract [en]

This paper is devoted to experimental study of capabilities and limitations of grindable thermocouples as applied to polymer materials sliding on metal. Chromel-alumel and chromel-copel grindable thermocouples have been developed and tested for wide ranges of contact pressure and sliding velocity. The background temperature of the sliding surface can be determined as the lower envelope of the signal from the grindable thermocouple. Steady and unsteady regimes of sliding have been investigated. For steady sliding, the accuracy of the temperature determination increases with measurement duration. In the case of unsteady sliding, accurate temperature determination requires multiple tests under the same conditions. The thickness of the thermocouple junction has been analyzed for correct comparison of experimental and calculated temperatures.

Keywords
Signal processing, Sliding, Temperature, Thermocouple
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-167022 (URN)10.1016/j.triboint.2015.03.015 (DOI)000355571500013 ()2-s2.0-84925831546 (Scopus ID)
Note

QC 20150610

Available from: 2015-06-10 Created: 2015-05-21 Last updated: 2018-01-11Bibliographically approved
Nosko, O., Alemani, M. & Olofsson, U. (2015). Temperature effect on emission of airborne wear particles from car brakes. In: Europe's Braking Conference and Exhibition 2015: . Paper presented at Europe's Braking Conference and Exhibition 2015. , EB2015-TEF-014
Open this publication in new window or tab >>Temperature effect on emission of airborne wear particles from car brakes
2015 (English)In: Europe's Braking Conference and Exhibition 2015, 2015, Vol. EB2015-TEF-014Conference paper, Published paper (Refereed)
Keywords
sliding, wear, temperature, airborne particles, car brakes
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-169694 (URN)10.13140/RG.2.1.1237.3209 (DOI)
Conference
Europe's Braking Conference and Exhibition 2015
Projects
Rebrake
Funder
EU, FP7, Seventh Framework Programme, 324385
Note

QC 20150624

Available from: 2015-06-22 Created: 2015-06-22 Last updated: 2018-01-11Bibliographically approved
Nosko, O. (2013). Effect of temperature on dynamic characteristics of a pad sliding on a disc. (Doctoral dissertation). Saitama: Saitama University
Open this publication in new window or tab >>Effect of temperature on dynamic characteristics of a pad sliding on a disc
2013 (English)Doctoral thesis, monograph (Other academic)
Alternative title[ja]
ディスク上を滑るパッドの動特性に与える温度の影響
Place, publisher, year, edition, pages
Saitama: Saitama University, 2013
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-173507 (URN)
Note

QC 20150914

Available from: 2015-09-14 Created: 2015-09-14 Last updated: 2018-01-11Bibliographically approved
Nosko, O. (2013). Partition of friction heat between sliding semispaces due to adhesion: deformational heat generation. International Journal of Heat and Mass Transfer, 64, 1189-1195
Open this publication in new window or tab >>Partition of friction heat between sliding semispaces due to adhesion: deformational heat generation
2013 (English)In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 64, p. 1189-1195Article in journal (Refereed) Published
Abstract [en]

Analytical expressions of heat-partition coefficient and contact temperatures for two sliding semispaces with account for adhesion-deformational heat generation and contact heat exchange have been obtained. The rate of deformational heat generation is assumed to decay exponentially with increase of distance from the interface. It has been shown that heat-generation configuration and the intensity of contact heat exchange have impact on heat partition only within a transient interval. The features of perfect thermal contact have been analyzed. Perfect thermal contact implies variation of heat partition in time. Heat partition and contact temperature for a semispace, sliding over a semispace with a constant temperature, have been studied. Adhesion-deformational heat generation results in a change of the direction of surface heat flow.

Keywords
Friction heat partition, Imperfect thermal contact, Sliding contact temperature, Analytical expressions, Constant temperature, Contact temperature, Friction heats, Heat partitions, Sliding contacts, Surface heat flow, Thermal contact, Adhesion, Friction, Heat exchangers, Heat generation
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-163233 (URN)10.1016/j.ijheatmasstransfer.2013.05.056 (DOI)000323236900113 ()2-s2.0-84879208251 (Scopus ID)
Note

QC 20150417

Available from: 2015-03-30 Created: 2015-03-30 Last updated: 2018-01-11Bibliographically approved
Nosko, O., Nagamine, T., Mori, H. & Sato, Y. (2013). Theoretical study of thermofrictional oscillations due to negative friction-temperature characteristic. Tribology International, 61, 235-243
Open this publication in new window or tab >>Theoretical study of thermofrictional oscillations due to negative friction-temperature characteristic
2013 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 61, p. 235-243Article in journal (Refereed) Published
Abstract [en]

Analytical study on oscillations of a body on a moving counterbody has been done by assuming imperfect frictional thermal contact and friction that decreases with contact temperature. It has been shown that stick-slip oscillation occurs due to decrease of friction coefficient when the body moves in the opposite direction to the counterbody. Dynamical characteristics, such as conditions for stable sliding and limit cycles, have been studied. Normal force between the bodies has significant effect on sliding stability.

Keywords
Contact temperature, Stick-slip, Analytical studies, Dynamical characteristics, Friction coefficients, Limit cycle, Normal forces, Sliding stability, Stick-slip oscillation, Theoretical study, Thermal contact, Slip forming
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-163235 (URN)10.1016/j.triboint.2012.12.007 (DOI)000317801400027 ()2-s2.0-84874600542 (Scopus ID)
Note

QC 20150409

Available from: 2015-03-30 Created: 2015-03-30 Last updated: 2018-01-11Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5259-1426

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