A one-dimensional thermal problem of friction was formulated, taking into account the contact pressure increase at the beginning of the process. The obtained solution to this problem allows for the quick calculation of the transient temperature distribution in a railway brake disc during single braking application. In order to validate the developed model, the experimental tests were performed for two friction pairs consisting of the cast iron brake disc and pads comprising two composite materials. Theoretical results were compared with the data measured by thermocouples embedded in the brake disc during the full-size dynamometer tests. The maximum temperature values found based on the analytical solution are convergent with the corresponding empirical data. The consistency of the results obtained for two friction couples demonstrates the usefulness of the proposed computational model.
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http://dx.doi.org/10.3390/ma15196821 | DOI Listing |
J Hazard Mater
January 2025
Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
This study investigates brake wear particle (BWP) emissions from light-duty electric vehicles (EVs) and heavy-duty vehicles (HDVs) using a self-developed whole-vehicle testing system and a modified brake dynamometer. The results show that regenerative braking significantly reduces emissions: weak and strong regenerative braking modes reduce brake wear PM by 75 % and 87 %, and brake wear PM by 90 % and 95 %, respectively. HDVs with drum brakes produce lower emissions and higher PM/PM ratios than those with disc brakes.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Faculty of Mechanical Engineering, Lublin University of Technology, 36 Nadbystrzycka St., 20-618 Lublin, Poland.
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.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
University of the Bundeswehr Munich, Faculty for Mechanical Engineering, Institute of Chemistry and Environmental Engineering, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany; Joint Mass Spectrometry Center at Comprehensive Molecular Analytics (CMA), Environmental Health Center, Helmholtz Munich, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany. Electronic address:
Non-exhaust emissions have gained increasing attention during the last years, with the upcoming EURO 7 regulation defining maximum PM emission factors for tire and brake emissions for the first time. This study, therefore, focusses on broadening the knowledge on chemical composition and physical characteristics of brake dust to define emission factors for heavy metal and organic pollutants. Particles from two pads were analyzed utilizing the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) brake cycle.
View Article and Find Full Text PDFSci Rep
October 2024
Department of Environmental Science, Stockholm University, 11418, Stockholm, Sweden.
Road traffic is an important source of urban air pollutants. Due to increasingly strict controls of exhaust emissions from road traffic, their contribution to the total emissions has strongly decreased over time in high-income countries. In contrast, non-exhaust emissions from road vehicles are not yet legislated and now make up the major proportion of road traffic emissions in many countries.
View Article and Find Full Text PDFEddy current brakes have been recently used for functional resistance training in individuals with neurological and orthopaedic disorders. These devices consist of a gearbox, a conductive disc, and permanent magnets that can be moved relative to the disc to alter resistance. However, current devices use a commercial planetary gearbox with a tall profile that sticks out from the leg, which affects wearability.
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