Abstract
Because braking of railway vehicle involves human life, it is very important to understand the friction and wear characteristics of brake friction materials. There are various types of brake friction materials, and their properties vary greatly depending on the operating environment and other factors. In this study, an experimental investigation of brake shoes for railway vehicles using acoustic emission (AE) sensing, which measures and analyzes AE waves generated by deformation and fracture phenomena at the friction interface, was performed. Experiments were conducted using a pin-on-disk friction and wear tester to measure friction force and AE signal for different brake shoe materials. The measured AE signal waveforms were subjected to a short-time Fourier transform, and the friction and wear phenomena were discussed from their frequency changes. In addition, it was found that there is a correlation between the AE signal amplitude and the coefficient of friction. Therefore, AE sensing enables in situ measurement of friction and wear state and frictional properties of brake shoe materials.
