Fractal characterization of wear particle accumulation in the wear process

To find a more accurate method characterizing wear particles, fractal geometry is applied in this paper describing wear particle accumulation. The wear experiments are carried out on a pin-on-disc test rig under dry friction conditions for a copper alloy pin and a steel disk. The results demonstrate that the logarithm of wear particle accumulation shows good linearity with the logarithm of the measured particle size. The relation between the accumulation of wear particles and the particle size presents a strong bi-fractal behavior. In addition, it is discovered that the fractal dimension of wear particle accumulation changes in different wear stages. The changes of the transition points of the bi-fractals correspond to the wear state variations.