Tread abrasion, rubber degradation and the mathematical morphology of tire debris particles

Some results about the mathematical morphology of tire debris particles are presented and related to other experimental data about the material degradation processes. Fractal analysis has been applied to three types of debris particles originated from the abrasion of silica filled tread rubber under different severity conditions. The structural fractal dimension, D_S , of the particle contour has served as a morphological descriptor (without being regarded as an intrinsic property of the fractured material !). D_S was estimated by processing optical images. A value of the morphological threshold which separates the textural from the structural domain in the RICHARDSON plot was determined in order to maximize discrimination betwen the three particle types and rank them by increasing values of D_S. The FOURIER transform followed by nonlinear filtering was applied to scanning electron microscope (SEM) images of tire debris particles undergoing leaching processes. Some morphological descriptors have been extracted, which quantify the effects of leaching on particle surfaces.