A novel hybrid AHP-SAW approach for optimal selection of natural fiber reinforced non-asbestos organic brake friction composites

In this paper, a novel hybrid AHP (analytic hierarchy process) - SAW (simple additive weighting) evaluation approach was proposed to select the preeminent brake friction composite formulation. Therefore, brake friction formulations containing varying amount (5–20 wt%) of natural fiber (ramie and hemp) were fabricated and tribo-evaluated on a Chase machine following IS 2742 (part 4). The experimental results such as performance coefficient of friction, fade-%, wear, recovery-%, friction fluctuations, stability and variability coefficient were taken as attributes for the performance assessment. The friction composites NF-1 reinforced with 5 wt% ramie fiber exhibit highest coefficient of friction, lowest fade-% with least friction variability and fluctuation. The composite NF-4 (containing 20 wt% ramie fiber) exhibited the highest recovery-% among all evaluated composites. Moreover, the friction composite NF-5 with 5 wt% hemp fibers exhibited the highest wear resistance and stability coefficient. The experimental outcomes reveal that no single formulation can satisfy all the performance attributes of brake friction composite materials. Therefore, the hybrid AHP-SAW approach was implemented to find out the best formulation which yields optimized tribological properties by considering all the performance attributes at a single time. The obtained optimization results revealed that the formulation NF-1 (having 5 wt% ramie fiber) exhibited the best combination of tribological properties desired for a brake friction material.