Research on the evolution of friction hot spots in vehicle disc brake during braking based on experiment.

At present, experimental research on the friction hot spots phenomenon of disc brake generally focuses on phenomenon analysis, without in-depth analysis of the relationship between the occurrence of hot spots, temperature, and deformation, result in unclear generation mechanism of friction hot spots. Therefore, this article first conducted a brake hot spot bench test, reproducing the phenomenon of brake hot spots at different speeds and brake pressures. A large amount of temperature and deformation field information during the formation process of brake hot spots was collected using infrared thermal camera, displacement sensors, vibration acceleration sensors, etc. Secondly, detailed data processing was carried out on the temperature and deformation fields, a three-dimensional spatial map of angle-radius-temperature was formed by unfolding the temperature field information collected by the infrared thermal camera along the circumferential direction, and the DTV, LRO, and ACZ information collected by displacement sensors and vibration acceleration sensors were innovatively convert from temporal domain into angular spatial domain, and the spatial domain information were then transformed into spatial frequency domain through the designed spatial Fourier transform. In addition, larger initial morphology signals were filtered out through wavelet decomposition. The above innovative data processing methods convert both the temperature and deformation time domain information during the hot spots generation into the spatial domain, so the interaction relationship between them and the hot spots can intuitively be analyzed. Based on this, this article finally analyzes the hot spots generation mechanism and draws the following key conclusions: (1) The generation of hot spots has critical speed and critical pressure; (2) The hot spots are alternately distributed on both sides of the brake disc, with a phase difference of 180°; (3) During the braking process, the deformation field changes before the temperature field, and the temperature field and the final number of hot spots depend on the stable deformation field; (4) During the evolution process of the deformation field, LRO and DTV mutually stimulate each other and alternately evolve towards higher order; (5) The main order and amplitude of the stable waveform of LRO (waviness distortion) are the decisive factors in the final number of hot spots. [ABSTRACT FROM AUTHOR]