A Homodyne Quadrature Laser Interferometer for  Micro-Asperity Deformation Analysis

Pogačnik, A.; Požar, Tomaž; Kalin, Mitjan; Možina, Janez

doi:10.3390/s130100703

Cited by 12 publications

(8 citation statements)

References 35 publications

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“…In addition, the temperatures developed in the tribological contact can also vary significantly with the counter-face material [6][7][8]. The temperature is difficult to predict theoretically, because the material's mechanical properties and deformation go thorough significant modifications within the contacts, and possibly even more with the uncertainty in the real contact area [8,9]. Currently, the gear temperature can be predicted based on standards [10,11], mostly derived from metal gear practice, for a very limited number of plastic materials.…”

Section: Introductionmentioning

confidence: 99%

The dominant effect of temperature on the fatigue behaviour of polymer gears

Kalin

Kupec

2017

Wear

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The testing procedures and reported tribological performance of polymer gears, which are seeing ever-increasing use by industry, still lack consistency and detail. One of the key parameters that affect a polymer's mechanical properties, interface contact conditions and, consequently, the wear and fatigue behaviour, is the temperature. Temperature is well known to have a critical influence on all polymers, much more so than on metals or other materials. However, the temperatureseven for the same load and velocityvary greatly with testing devices, gear sizes and shapes, surrounding environment, as do the cooling and heating rates. Moreover, the temperature, either root, flank or bulk, also varies with the operating conditions, meaning that even in the same S-N curve data at different stresses we actually obtain different temperatures. This suggests that the results from different tests and even different load levels, which are not temperature controlled, cannot be directly compared due to the important influence of the temperature on the polymers. This work presents the results of POM gears tested against steel gears under well-controlled temperature conditions, providing various S-N curves obtained at 30 ˚C, 50 ˚C and 70 ˚C that were kept constant at the gear root for three torque values (1.0 Nm, 1.2 Nm and 1.4 Nm), and these are compared to data obtained under conditions that are typically considered to be "room temperature", which is in fact an uncontrolled temperature. The results confirm the important effect of the temperature on the fatigue life of POM gears, i.e., when kept at low temperature (30 °C), the fatigue life of POM gears is greatly improved.

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Section: Introductionmentioning

confidence: 99%

The dominant effect of temperature on the fatigue behaviour of polymer gears

Kalin

Kupec

2017

Wear

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“…From our results it seems that the material properties change with load, probably due to strainhardening [33] and [45] or induced hydrostatic stresses [46]; however, the actual geometrical properties of the asperity [21] and [30] and interactions between neighbouring asperities [14] cannot be excluded from any influence since they also change simultaneously. This particular issue should be further analysed in detail to properly understand the mechanisms behind multi-asperity contact behaviour.…”

Section: Discussionmentioning

confidence: 68%

“…Multi-asperity contacts and the real contact area between two realistic and rough flat surfaces have rarely been investigated experimentally [23], [28] and [30], and no detailed study with a submicron resolution of asperity growth has been presented, to the best of our knowledge. However, multi-asperity contact analyses are of great importance since the asperities interact with each other and influence how much load each asperity will carry.…”

Section: Introductionmentioning

confidence: 99%

In-situ Observations of a Multi-Asperity Real Contact Area on a Submicron Scale

Zugelj¹,

Kalin²

2017

SV-JME

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“…However, the intensity and frequency instability of the light source dominates the measurement uncertainty of displacement-measuring interferometers. Normally, thermally-stabilized He-Ne lasers, of single or dual frequency, are used [1][2][3][4]. However, a frequency stability in the order of 10 −6 -10 −8 and an intensity stability of 0.1% are insufficient for measurements at a nanometer order of accuracy.…”

Section: Introductionmentioning

confidence: 99%

A Displacement Measuring Interferometer Based on a Frequency-Locked Laser Diode with High Modulation Frequency

Hoang

et al. 2020

Applied Sciences

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Laser interferometers can achieve a nanometer-order uncertainty of measurements when their frequencies are locked to the reference frequencies of the atom or molecule transitions. There are three types of displacement-measuring interferometers: homodyne, heterodyne, and frequency modulation (FM) interferometers. Among these types of interferometer, the FM interferometer has many advantageous features. The interference signal is a series of time-dependent harmonics of modulation frequency, so the phase shift can be detected accurately using the synchronous detection method. Moreover, the FM interferometer is the most suitable for combination with a frequency-locked laser because both require frequency modulation. In previous research, low modulation frequencies at some tens of kHz have been used to lock the frequency of laser diodes (LDs). The low modulation frequency for the laser source means that the maximum measurement speed of the FM interferometers is limited. This paper proposes a novel contribution regarding the application of a high-frequency modulation for an LD to improve both the frequency stability of the laser source and the measurement speed of the FM interferometer. The frequency of the LD was locked to an I2 hyperfine component at 1 MHz modulation frequency. A high bandwidth lock-in amplifier was utilized to detect the saturated absorption signals of the I2 hyperfine structure and induce the signal to lock the frequency of the LD. The locked LD was then used for an FM displacement measuring interferometer. Moreover, a suitable modulation amplitude that affected the signal-to-noise ratio of both the I2 absorption signal and the harmonic intensity of the interference signal was determined. In order to verify the measurement resolution of the proposed interferometer, the displacement induced by a piezo electric actuator was concurrently measured by the interferometer and a capacitive sensor. The difference of the displacement results was less than 20 nm. To evaluate the measurement speed, the interferometer was used to measure the axial error of a high-speed spindle at 500 rpm. The main conclusion of this study is that a stable displacement interferometer with high accuracy and a high measurement speed can be achieved using an LD frequency locked to an I2 hyperfine transition at a high modulation frequency.

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A Homodyne Quadrature Laser Interferometer for Micro-Asperity Deformation Analysis

Cited by 12 publications

References 35 publications

The dominant effect of temperature on the fatigue behaviour of polymer gears

The dominant effect of temperature on the fatigue behaviour of polymer gears

In-situ Observations of a Multi-Asperity Real Contact Area on a Submicron Scale

A Displacement Measuring Interferometer Based on a Frequency-Locked Laser Diode with High Modulation Frequency

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