Beyond Hot Spots: Dual-Risk Thermal Instability in a 5 mm Asperity-Resolved Brake Contact Interface

Pengfei Cui; Liangbi Wang

doi:10.62051/ijmee.v8n5.04

Authors

Pengfei Cui School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou Gansu, 730070, China; Key Laboratory of Railway Vehicle Thermal Engineering, Ministry of Education, Lanzhou Gansu, 730070, China
Liangbi Wang School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou Gansu, 730070, China; Key Laboratory of Railway Vehicle Thermal Engineering, Ministry of Education, Lanzhou Gansu, 730070, China

DOI:

https://doi.org/10.62051/ijmee.v8n5.04

Keywords:

Rough Brake Contact Interface, Thermo-mechanical Coupling, Load-Speed Effect, Plastic Dissipation, Thermal Instability

Abstract

To reveal the differences in local thermal instability at rough braking interfaces under different load and rotational-speed conditions, a three-dimensional transient thermo-mechanically coupled finite element model was established. A 5×5×1 mm³ single-sided rough surface region containing 496 asperities was used as the computational domain. Temperature, stress, affected depth, energy dissipation, and frequency-domain fluctuations were compared under three operating conditions. The results show that, when the load increases from 12 kN to 16 kN, the maximum temperature rises from 957.03 °C to 993.10 °C, and the plastic-dissipation depth increases from 0.204 mm to 0.300 mm. Under a 16 kN load, reducing the rotational speed from 48 rad/s to 42 rad/s lowers the maximum temperature to 709.20 °C, but increases the root-mean-square stress amplitude to 265.79 MPa. Lowering the rotational speed can alleviate thermal concentration, but it cannot eliminate contact reconstruction and stress fluctuation induced by high load. Braking risk should therefore be evaluated jointly using the dual indicators of temperature concentration and stress fluctuation.

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