https://orcid.org/0000-0002-2734-1425
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ABSTRACT
This experimental mathematical work aims to analyse the results obtained from the heat transfer of a typical automotive disc brake and thus compare the behaviour of heat dissipation of this mechanical element under different operating conditions. The results demonstrate that the disc brakes can be used effectively in severe operational conditions with a speed of 36 km/h and an ambient temperature of 25°C, without affecting the safety of the occupants or the braking system. The use of semi-metallic pads increases the temperature over the wear track superficial temperature by around 20% more than the asbestos pad, but the material removal during sliding is around ~2.5 times more for the asbestos pad due to the coupling in the tribosystem (pad and disc brake). The heat dissipation in the disc brakes depends on the geometry of the disc, the material from which it is manufactured, the material of the pad, the weight of the vehicle, and the operating conditions, as it could be verified with the mathematical and experimental results, thus validating the contribution of the effectiveness of the braking process during its real operation.
Nomenclature
| A | = | Heat transfer area. (m2). |
| a | = | Deceleration. (m/s2). |
| aMax | = | Maximum braking deceleration. (m/s2). |
| CP | = | Specific heat of the material. (J/Kg×°C). |
| EDisc | = | Disc brake energy. (J). |
| Ef | = | Energy to dissipate by the braking system. (J) |
| EFront axle | = | Front axle energy. (J). |
| EPad | = | Energy in the pad. (J). |
| FC | = | Force in cylinder. (N). |
| Ff | = | Braking force. (N). |
| FP | = | Torque force on pedal. (N). |
| FPedal | = | Pedal force. (N). |
| fr | = | Rolling resistance coefficient. (0.01225 Dimensionless). |
| FS | = | Force produced by the brake booster. (N). |
| g | = | Acceleration of gravity. (9.81 m/s2). |
| k | = | Thermal conductivity. (J/s×m×°C). |
| mD | = | Disc brake mass. (3.04 Kg). |
| mv | = | Vehicle mass. (Kg). |
| Rr | = | Rolling resistance. (198.284 N). |
| t | = | Newton cooling time. (s). |
| T | = | Environment temperature. (22°C). |
| Ti | = | Instantaneous temperature at all times. (°C). |
| U | = | Coefficient of surface thermal transmission of the material. (J/s×m2×°C). |
| V | = | Vehicle speed. (36 Km/h). |
| VF | = | Final vehicle speed. (m/s). |
| Vi | = | Initial vehicle speed. (m/s). |
| VP | = | Peripheral speed of the disc. (m/s). |
| W | = | Vehicle weight. (1,650 Kg=16,186.5 N). |
| X | = | Percentage of adherence. (%). |
| α | = | Thermal diffusivity. (m2/s). |
| γF | = | Rotating mass coefficient. (Dimensionless). |
| μ | = | Coefficient of adhesion between tire and road. (μ=aMax/g or 0.85 Dimensionless). |
| Ρ | = | Material density. (Kg/m3). |
Disclosure statement
No potential conflict of interest was reported by the author(s).
Author contributions
R. A. García-León, Investigation, Supervision, Project administration, Conceptualization, Methodology, Formal analysis, original draft – preparation, writing – review & editing.
G. Guerrero-Gómez and N. Afanador-García, Investigation, Methodology, Formal analysis, other contribution.
Data availability
Data is openly available in a public repository that does not issue DOIs. The data that support the findings of this study are openly available in [Universidad Francisco de Paula Santander Ocaña repository] at [http://repositorio.ufpso.edu.co/handle/123456789/382], reference number [Thesis: 2246-2020].
Additional information
Funding
Notes on contributors
R. A. García-León
R. A. García-León, received the BSc. in Mechanical Engineering from the Universidad Francisco de Paula Santander Ocaña, Colombia, in 2014, MSc. in Industrial Engineering of the Universidad de Pamplona, Colombia. He is Ph.D. in Scientist of Mechanical Engineering at InstitutoPolitecnico Nacional. He is linked since 2015 as a professor in the Department of Mechanical Engineering of the Faculty of Engineering of the Universidad Francisco de Paula Santander, Ocaña, Colombia. Researcher and coordinator of the research line Materials and Industrial Processes in the INGAP Research Group. Also, he is member of the Surface Engineering Group in Mexico. His areas of interest are mainly the development of mechanical systems, industrial processes, engineering materials, wear, and tribology.
G. Guerrero-Gómez
G. Guerrero-Gómez, received the BSc. Mechanical Engineer from Universidad Francisco de Paula Santander, Specialist in University Teaching Practice from Universidad Francisco de Paula Santander Ocaña, Master in Advanced Energy Systems from Universidad de Santander. Full-time teacher since 2011 and Researcher of the GITYD group of the Faculty of Engineering at the Francisco de Paula Santander Ocaña University.
N. Afanador-García
N. Afanador-García, received the BSc. Eng. in Civil Engineering and graduate in mathematics and Physic in 1990, the MSc degree Civil Engineering with an emphasis in structures at the Universidad of the Andes Colombia in 2008 and actually, he is PhD in Structures at the University of Brasilia. Since 2003 to actually, he works for Francisco of Paula Santander University Ocaña in civil engineering department.