Parametric study, optimisation and ranking analysis of Grewia Optiva Fibre/Dolomite based hybrid composites using hybrid MCDM technique

This study explores the development of sustainable epoxy composites reinforced with 20 wt% Grewia optiva natural fiber and enhanced with varying concentrations of dolomite particulate filler (0, 5, 10, and 15 wt%) to optimize mechanical and tribological performance. Composites were fabricated using a controlled hand lay-up technique, followed by comprehensive evaluation of their physical, mechanical, and wear characteristics. The incorporation of dolomite significantly improved surface hardness by up to 12.2% and Charpy impact strength by an impressive 160%, highlighting enhanced energy absorption and resistance to surface deformation. However, an inverse relationship was observed for tensile and flexural strengths, which declined by 31.9% and 33.7%, respectively, at the highest filler loading, attributed to increased stress concentration effects within the matrix. Tribological assessments conducted over a 1500 m sliding distance under controlled load and speed conditions demonstrated that the 15 wt% dolomite-filled composite (EGD15) achieved superior wear resistance, reducing the specific wear rate by approximately 28.79% compared to the unfilled counterpart. Detailed worn-surface morphology analysis revealed that dolomite particles stabilized the composite surface by promoting a shift from severe wear to more controlled mechanisms such as micro-cutting and micro-ploughing, thereby minimizing micro-damage. To address the complex trade-offs between mechanical strength and wear resistance, a multi-criteria decision-making approach using the Analytic Hierarchy Process (AHP) integrated with a Proximity Indexed Value (PIV) framework was employed. The findings underscore the viability of Grewia optiva–dolomite hybridization as a promising, eco-friendly strategy for producing lightweight, wear-resistant epoxy composites suited for advanced engineering applications.