Composite friction materials based on metallic fillers: Sensitivity of μ to operating variables

Variation in μ during braking with operating variables is of major concern to the composite manufacturers, since it is composition specific. The frictional response of a multicomponent NAO friction composite is highly complex under a set of dynamically variable pressure and speeds. This paper discusses the sensitivity of friction (μ) towards braking pressure and sliding speed of selected composites based on variation in an inclusion of metallic fillers, viz. brass, copper and iron. Among metallic fillers, copper powder proved very effective in reducing μ-sensitivity to dynamic variations in pressure and speed. Regression analysis of μ values was also carried out.

Research highlights
► New approach defined in this study on an RSP proved to have potential to study load-speed sensitivity of μ.
► This method has significant advantages such as very limited infrastructure, substantially less testing time and man-power along with extremely low cost as compared to the standard method on full scale dynamometer.
► Use of metallic ingredients in NAO friction composites affected all performance properties in a beneficial way. Cu was most effective in boosting TC significantly followed by brass and iron.
► Increased TC of the composites due to metallic fillers was the main reasons for improved friction performance.
► Regression analysis of μ values was also carried out.