Correlation between solid–solid contact ratios and lubrication regimes measured by a refined electrical resistivity circuit

Rosenkranz, Andreas; Martin, B.G.; Bettscheider, Simon; Gachot, Carsten; Kliem, H.; Mücklich, Frank

doi:10.1016/j.wear.2014.08.018

Cited by 30 publications

(19 citation statements)

References 21 publications

(47 reference statements)

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“…As outlined in Section 2.5, those signals were used to determine the solid-solid contact ratio by dividing the integral of the output signal over the input signal. [30]. Since the sphere and sample are well separated, the output signal is zero, which is also reflected in the calculated solid-solid contact ratio of 0.44%.…”

Section: Calibration Of the Electrical Resistivity Circuitmentioning

confidence: 86%

“…This suggests that irregularities in the surface topography (ball and/or polished reference) do not significantly influence the results of the experiment. [30]. Since the sphere and sample are well separated, the output signal is zero, which is also reflected in the calculated solid-solid contact ratio of 0.44%.…”

Section: Calibration Of the Electrical Resistivity Circuitmentioning

confidence: 86%

“…This can be a helpful information in order to explore the differences in the frictional behavior between laser-patterned samples and the polished reference. An experimental set-up introduced by Rosenkranz et al [30] was used to determine the respective ratios. The respective set-up is illustrated in Figure 1.…”

Section: Electrical Resistivity Circuitmentioning

confidence: 99%

“…Figure 5 shows the respective temporal evolution of the electrical input and output signals at three different times. The input signal is a rectangular signal as outlined in Section 2.5 and [30]. Since the sphere and sample are well separated, the output signal is zero, which is also reflected in the calculated solid-solid contact ratio of 0.44%.…”

Section: Calibration Of the Electrical Resistivity Circuitmentioning

confidence: 99%

“…Rosenkranz et al developed an electrical resistivity set-up in order to measure the amount of solid-solid contact with high temporal and spatial resolution. This resolution is necessary since changes in the contact situation under mixed lubrication due to contacting asperities and variations in the oil film happen at a rather high temporal rate as well as in small spatial dimensions [30]. Grützmacher et al performed unidirectional ball-on-disk experiments with polished reference samples dependent on oil viscosity used and angular velocity adjusted by the respective track radius.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Low Friction and High Solid-Solid Contact Ratio—A Contradiction for Laser-Patterned Surfaces?

2017

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Abstract:Recording of Stribeck-like curves is a common way to study the effect of laser-patterned surfaces on the frictional efficiency. However, solely relying on the coefficient of friction when identifying the lubrication regime and the underlying working principles can be misleading. Consequently, a ball-on-disc tribometer was combined with an electrical resistivity circuit to simultaneously measure Stribeck-like curves and solid-solid contact ratios for polished and laser-patterned samples. Line-like surface patterns with different periodicities were produced by direct laser interference patterning on steel substrates (AISI304). The reference shows a Stribeck-like behavior well correlating with the contact ratios. The behavior deviates for high sliding velocities (high contact ratios) due to a loss of lubricant induced by centrifugal forces pulling the lubricant out of the contact zone. In contrast, the solid-solid contact ratio of the laser-patterned samples is around 80% for all sliding velocities. Those values can be explained by higher contact pressures and the structural depth induced by the surface topography which make a full separation of the surfaces unlikely. Despite those high values for the contact ratio, laser-patterning significantly reduces friction, which can be traced back to a reduced real contact area and the ability to store oil in the contact zone.

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Section: Calibration Of the Electrical Resistivity Circuitmentioning

confidence: 86%

Section: Calibration Of the Electrical Resistivity Circuitmentioning

confidence: 86%

Section: Electrical Resistivity Circuitmentioning

confidence: 99%

Section: Calibration Of the Electrical Resistivity Circuitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Low Friction and High Solid-Solid Contact Ratio—A Contradiction for Laser-Patterned Surfaces?

2017

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Improving Triboelectric Nanogenerators Performance Via Interface Tribological Optimization: A Review

Xiao,

Wang,

Wang

et al. 2024

Adv Funct Materials

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Triboelectric Nanogenerators (TENGs) represent a novel energy harvesting technology that combines contact electrification (CE) and electrostatic induction, rendering them a promising solution for self‐powering micro smart devices and addressing the energy crisis. At present, the efficiency and longevity of TENGs have been substantially improved through various methods. These advancements have overcome the limitations caused by interface friction, expanding the scalability and practical applications of TENGs. Specifically, it has been demonstrated that interface tribological optimization can simultaneously enhance electrical output performance and durability. This review will initially discuss the fundamental mechanism of TENGs and its profound connection with tribology. Subsequently, the optimization of interface tribology, encompassing structure design, surface modification, and lubricant utilization, will be comprehensively reviewed. Finally, the current challenges and future prospects will be summarized.

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An experimental study on the applicability of acoustic emission to detection of lift-off state in gas foil bearings

Ahmadzadeh,

Kliemank,

Gühmann

et al. 2024

Forsch Ingenieurwes

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Gas foil bearings (GFBs) are fluid dynamic bearings with applications in high-speed lightweight machinery. One of the important parameters in GFBs is the lift-off speed. It indicates a speed above which there is no occurrence of dry friction and wear between the rotor and bearing, the so-called lift-off state. There are various techniques for determination of the lift-off state. However, they come with major limitations and complexities for use in real-world applications, especially in high-speed machinery. In recent years, monitoring the lift-off condition in journal bearings based on acoustic emissions (AE) has been investigated and shown to be suitable for this type of bearing. Nevertheless, its applicability to GFBs is yet not known, as there has been no practical investigation on AE signals in GFBs. In the present work, the applicability of AE measurements to detection of lift-off state in GFBs is explored experimentally based on previous studies on journal bearings. The results demonstrate that AE measurements are a potential alternative to conventional methods in determining the lift-off state in GFBs. The comparison between features of AE signals, measured at two different locations on the bearing, with the friction torque as the reference exhibits the applicability of AE measurements to detection of lift-off state.

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Correlation between solid–solid contact ratios and lubrication regimes measured by a refined electrical resistivity circuit

Cited by 30 publications

References 21 publications

Low Friction and High Solid-Solid Contact Ratio—A Contradiction for Laser-Patterned Surfaces?

Low Friction and High Solid-Solid Contact Ratio—A Contradiction for Laser-Patterned Surfaces?

Improving Triboelectric Nanogenerators Performance Via Interface Tribological Optimization: A Review

An experimental study on the applicability of acoustic emission to detection of lift-off state in gas foil bearings

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