Mulu Gidey2025-12-102025-11-24https://repository.mu.edu.et/handle/123456789/1076Background: A bumper is an essential part of a vehicle, engineered to absorb impacts and shield the front and rear during low-speed collisions. This research focuses on creating glass/sisal and sheep wool fiber-reinforced composites for bumpers, meeting the demand for lightweight, sustainable materials while fostering local economic growth through job creation. It seeks to substitute traditional heavy materials, decrease costs, and advance sustainability initiatives within the automotive sector. Objective: The primary objective of this research is to develop and select hybrid composite materials that combine glass, sisal, and wool fibers reinforced with epoxy resin for use in vehicle bumpers. Specific goals include enhancing the mechanical properties of natural fibers and optimizing the composite design for performance and cost-effectiveness. Method: The methodology involves treating sisal and wool fibers with sodium hydroxide to enhance their mechanical properties, followed by the fabrication of composites using hand lay-up techniques. A comprehensive series of mechanical tests based on ASTM standards assesses properties such as tensile strength, impact resistance, and water absorption. Result: The composites demonstrate a tensile strength of 114.07 MPa, impact resistance of 112.5 kJ/m², and the composite bumper can absorb a maximum energy of 49.34kJ/m2 with speed 2.22m/s, and also a weight of 3.8 kg, significantly lighter than traditional steel bumpers (5.16 kg). Software analysis using Genetic Algorithms optimized the design, achieving a maximum stress of 31 Mpa and a deflection of 89 mm under impact conditions, indicating superior performance compared to conventional materials. This study supports the transition to environmentally friendly materials in the automotive industry. Conclusion: This research substantiates that glass/sisal and wool fiber-reinforced composites are viable alternatives for automotive bumper applications, offering improved performance and reduced environmental impact, to reduced fuel consumption and local economic growth. The findings support the ongoing transition toward sustainable materials in the automotive industry and highlight the economic benefits associated with local fiber utilization.enBumperHybrid Glass/Sisal/Wool fiber Reinforced Compositereinforcementcompositetensile strengthimpact resistanceoptimization.Thesis