Development and Numerical Investigation of Eco-Friendly Brake Pads Using Cola Nut as Filler Material

<p>The growing environmental and health concerns associated with asbestos-based and metallic brake pads have intensified the search for sustainable friction materials. This study developed and numerically investigated eco-friendly brake pads using cola nut shell powder as a bio-based filler material. Cola nut shells were processed into powder, sieved to a particle size range of 150–250 μm, and characterized to determine their physical, chemical, and thermal suitability for brake-pad composite formulation. The material exhibited a density of 1.38 ± 0.03 g/cm³, moisture content of 5.2 ± 0.4%, cellulose content of 42.5 ± 2.1%, lignin content of 28.7 ± 1.8%, hemicellulose content of 19.6 ± 1.5%, ash content of 4.0 ± 0.3%, and thermal stability of 287°C. These properties indicate good reinforcement potential, acceptable thermal resistance, and suitability for incorporation into phenolic resin-based brake composites. The study further proposed a coupled thermo-mechanical numerical framework to predict temperature distribution, contact pressure, deformation, and stress behaviour under braking conditions. Experimental validation was designed using tribological, hardness, mass-loss, thermal, surface morphology, and statistical analyses to evaluate friction stability, wear resistance, and structural integrity. The findings suggest that cola nut shell powder is a promising alternative filler for asbestos-free brake pads, particularly in regions where cola nut waste is locally available. The study contributes to sustainable automotive material development by converting agricultural waste into a value-added engineering product while reducing dependence on hazardous conventional brake-pad constituents and supporting cleaner, affordable, locally sourced friction-material innovation for future automotive applications and sustainable industrial development in emerging economies globally.</p>