Signal Detection by Sensors and Determination of Friction Coefficient During Brake Lining Movement

Our plain-English summary of Signal Detection by Sensors and Determination of Friction Coefficient During Brake Lining Movement, by L. Hrabovský, V. Molnár, G. Fedorko, et al (Sensors, 2024).

The study

• Authors: L. Hrabovský, V. Molnár, G. Fedorko, N. Mikusova, J. Blata, J. Fries, T. Jachowicz
• Journal: Sensors
• Published: 2024;24(24)
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

This article presents a laboratory device by which the course of two signals can be detected using two types of sensors-strain gauges and the DEWESoft DS-NET measuring apparatus. The values of the coefficient of friction of the brake lining when moving against the rotating shell of the brake drum were determined from the physical quantities sensed by tensometric sensors and transformed into electrical quantities. The friction coefficient of the brake lining on the circumference of the rotating brake disc shell can be calculated from the known values measured by the sensors, the design dimensions of the brake, and the revolutions of the rotating parts system. The values of the friction coefficient were measured during brake lining movement. A woven asbestos-free material, Beral 1126, which contained brass fibers and resin additives, showed slightly higher values when rotating at previously tested speeds compared to the friction coefficient values obtained when the brake drum rotation was uniformly delayed. The methodology for determining the friction coefficient of the brake lining allowed the laboratory device to verify its magnitude for different friction materials under various operating conditions.

In plain English

This was a laboratory engineering study, not a study of asbestos exposure or health. The authors built a test device at VSB-Technical University of Ostrava to measure the friction coefficient of a double-jaw drum brake, which is a measure of how strongly a brake lining grips. The lining tested was Beral 1126, which the article describes as a woven asbestos-free friction material containing brass fibers. Sensors recorded the force on the brake and the torque on the shaft at speeds from 148.5 to 748.2 revolutions per minute. A second method calculated friction from how long the spinning parts took to stop. With the drum turning, the highest value, 0.469 plus or minus 0.031, came at the lowest speed, and the average was 0.376. The braking-time method gave an average of 0.353, which the authors reported as 93.9% of 0.376. They attributed the difference to difficulty reading braking times accurately. All tests used clean, dry surfaces. The authors concluded that the device can determine the lining's friction coefficient with sufficient accuracy.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory engineering experiment: design of a test device and repeated sensor measurements of brake-lining friction (no human subjects)
• Who was studied: No people were studied. The test object was the Beral 1126 brake lining glued to the shoes of a double-jaw brake, tested under dry conditions in a laboratory at VSB-Technical University of Ostrava, Czech Republic
• Exposure: No asbestos exposure was studied. The lining tested is described as a woven asbestos-free friction material containing brass fibers. It was run against a rotating brake drum at frequency-converter settings of 10 to 50 Hz (148.5 to 748.2 revolutions per minute)
• Main results:
  • With the drum rotating, the friction coefficient was highest at the lowest speed (10 Hz setting, 148.5 revolutions per minute): 0.469 plus or minus 0.031
  • The average friction coefficient from force and torque measurements while the drum rotated (Tables 2 to 4) was 0.376
  • The average friction coefficient calculated from braking time was 0.353
  • The braking-time average (0.353) was 93.9% of the rotating-drum average (0.376)
• The authors' conclusion: The authors concluded that the friction coefficient of the brake lining can be determined with sufficient accuracy on the device they designed
• Limitations the authors state:
  • The authors attributed the difference between the two methods' results to difficulty obtaining completely accurate braking-time readings
  • Measurements were made only on clean, dry brake surfaces. Wet or contaminated conditions were left for future research
  • Only one lining material was tested, and the authors did not compare different friction materials

Topics

Medical terms in this study, explained in our Lexicon: Brake Lining.

Related studies

• Asbestos exposure during brake lining maintenance and repair — A.N. Rohl, A.M. Langer, et al. (1976)
• Environmental and occupational health hazards associated with the presence of asbestos in brake linings and pads (1900 to present): a "state-of-the-art" review — D.J. Paustenbach, B.L. Finley, et al. (2004)
• Asbestos bodies in bronchoalveolar lavage fluids of brake lining and asbestos cement workers — P. Dumortier, P. De Vuyst, et al. (1990)
• Asbestos exposure during routine brake lining manufacture — H. Kakooei, M. Sameti, et al. (2007)
• Experimental studies on the effects of heated chrysotile asbestos and automobile brake lining dust injected into the body cavities of mice — J.M. Davis, S.W. Coniam (1973)
• Asbestos fibres in the lungs of an American mechanic who drilled, riveted, and ground brake linings: a case report and discussion — M.M. Finkelstein (2015)

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