EXPERIMENTAL STUDY ON THE MULTIFRACTAL EVOLUTION OF FRICTION TEMPERATURE

Abstract

The experiments were performed by sliding a pin against a plate under lubricated sliding condition. The friction temperature signal was measured by a thermocouple through the wear life. The multifractal spectrum was utilized to study the dynamic evolution of the friction temperature. The width of the multifractal spectrum, [Formula: see text], and the difference between the fractal dimensions of the subset with the largest singularity exponent and that with the smallest singularity exponent, [Formula: see text], are computed for qualitative analysis. The results demonstrate that the friction temperature signal possesses multifractal properties. In the running-in period, both [Formula: see text] and [Formula: see text] decrease gradually, and the spectrum changes from a wide, hook-like shape to a narrow, bell-like shape. In the steady state, [Formula: see text] maintains at a small value, [Formula: see text] fluctuates slightly around 0, and the narrow, bell-like shape of the spectrum persists. In the increasing friction, [Formula: see text] and [Formula: see text] increase gradually, and the spectrum changes from the narrow, bell-like shape to the wide, hook-like shape. The results provided insight into the dynamic behavior of friction system.