How to determine the number of asperity peaks, their radii and their heights for engineering surfaces: A critical appraisal

Pogačnik, A.; Kalin, Mitjan

doi:10.1016/j.wear.2013.01.105

Cited by 33 publications

(13 citation statements)

References 26 publications

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“…Additionally, standard deviation of asperity heights, radius of an asperity peak, as well as density of asperities are required for contact pressure calculation and summarized in a so-called elastic factor. By now no generally accepted method exists to determine these asperity peak properties [12]. Consequently, the elastic factor varies in different publications between 1 × 10 −4 and 5 × 10 −2 , e.g., [9,[13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

et al. 2018

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This paper focuses on the operating behavior of journal bearings for industrial machinery application during run-ups. For this purpose, a numerical simulation code that is based on a two-dimensional extended and generalized Reynolds equation and a full three-dimensional energy equation, was advanced by a theoretical model considering the effects of mixed friction and warming of journal components during start-up. The mixed friction routine contained the elastic half-spaces model proposed by Boussinesq, which considers the influence of rough surfaces by implementing flow factors and calculates additional stiffness and dissipation in areas with solid interactions. Furthermore, a transient term was added in the energy equation to consider the thermal inertia of journal, and bearing to ensure a realistic heating during run-ups. Results of the prediction were compared to experimental data taken from a special test rig built up for validation procedures. Besides the conventional sensors for temperature, oil flow, and relative motion between shaft and stator, a contact voltage measurement was installed to determine the intensity of mixed friction. The evaluation of experimental data by Stribeck curves, based on a shaft torsion measurement, indicated a significant influence of run-up time on frictional moment. The friction coefficient of the rotor bearing system was strongly influenced by the run-up time. A short run-up time reduced the frictional coefficient in the mixed lubrication regime while the opposite behavior was observed in the hydrodynamic lubrication regime. The numerical code predicted these tendencies in good agreement with experimental data, however, only if the transient energy model was applied.

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Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

et al. 2018

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“…Counting the asperity number is difficult practically because the definition of the asperity shape is obscure due to the awkward shape. The definition using the three-point or sevenpoint method of the countable asperity is discussed [42]. The number of the asperities is also sensitive to the measurement resolution.…”

Section: Evaluation Of the Real Contact Area Ratio Using The Surface mentioning

confidence: 99%

Temperature rise of diamond-like carbon during sliding: Consideration of the real contact area

Yamamoto

Liskiewicz

Fujimura

et al. 2019

Tribology International

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The real contact area based on modified Hertzian theory derived from sinusoidal asperity model is introduced and the measurement method for the real contact area is proposed. The real contact approach is compared with the Greenwood-Williamson theory showing good agreement between the two methods. The separation between the contact surfaces is estimated by taking into account the surface roughness. The temperature rise at the sliding interface between the DLC coating and E52100 steel is evaluated experimentally by the thermal indicator paint method, and the real contact area ratio is estimated from the temperature simulation data. The temperature rise is discussed from the entropy balance point of view induced from the real contact area and the frictional energy.

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“…These contact models rely on material properties and surface topography of the contacting surfaces as input parameters. Hence, the relevance of the contact models is dependent on their inherent assumptions and the accuracy with which the input parameters are determined [3,4]. The surface topography of an engineering surface can be determined experimentally using e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Few works have compared the surface topography parameters calculated with different deterministic methods. Pogacnik and Kalin evaluated the surface topography parameters for 2D profiles [4] and for 3D topography [25] obtained from real engineering surfaces with different roughness. They used a deterministic approach based on three, five, seven and nine neighboring points of a 2D and 3D surface characterization and concluded that the choice of the lateral resolution, roughness, and especially the number of neighboring points significantly affects the surface topography parameter results.…”

Section: Introductionmentioning

confidence: 99%

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Comparing surface topography parameters of rough surfaces obtained with spectral moments and deterministic methods

Kalin

Pogačnik

Etsion

et al. 2016

Tribology International

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Understanding contact between rough surfaces is of critical importance to the design of many engineering applications. Contact models rely on material properties and surface topography of the contacting surfaces as input parameters. Hence, the relevance of the contact models is dependent on their inherent assumptions and the accuracy with which the input parameters are determined. We have evaluated the difference between the surface topography parameters calculated with a statistical and deterministic approach for actual engineering surfaces. We have found topography values that change up to 300% depending on the method used, and attribute this to the stringent definition of an asperitypeak in the case of deterministic analysis as opposed to statistical analysis, which not only considers asperity-peaks but also asperity-shoulders.

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How to determine the number of asperity peaks, their radii and their heights for engineering surfaces: A critical appraisal

Cited by 33 publications

References 26 publications

Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

Temperature rise of diamond-like carbon during sliding: Consideration of the real contact area

Comparing surface topography parameters of rough surfaces obtained with spectral moments and deterministic methods

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