Multi- criteria optimization of lightweight expanded steel mesh-FRP composites for improved flexural and energy absorption performance

• The study examines the impact of various stacking configurations on the flexural strength, modulus, and strain of composite structures, revealing differences in mechanical response. • The study assesses the influence of expanded stainless-steel mesh size (fine, medium, and coarse configurations) on flexural characteristics and energy absorption capacities. • Analysis of loading Patterns (horizontal and vertical loading situations) demonstrates notable disparities in strength, strain, and absorbed energy contingent upon the loading direction. • The investigation utilizes MCDM strategies, including the TOPSIS method, to identify the optimal composite configuration based on several performance parameters. • Detailed damage assessments reveal fracture patterns, crack propagation, and failure modes in various configurations, providing insight on structural durability and failure causes. A promising alternative to the brittleness and low absorbed energy of conventional fiber-reinforced polymers (FRPs) can be offered by hybrid composites, which integrate FRPs with metallic reinforcements. In this investigation, hybrid composites of woven E-glass fibers and expanded steel meshes comprising various steel mesh sizes (fine, medium, and coarse) were manufactured adopting a hand layup technique with epoxy resin and compression molding. Two stacking configurations were investigated: steel mesh reinforcement in the outer and core layers. In accordance with ASTM D790 standards, three-point flexural tests were performed for evaluating mechanical performance under both horizontal and vertical loading patterns. A multi-criteria decision-making strategy (TOPSIS: Technique for Order Preference by Similarity to Ideal Solution) was utilized to determine the most effective configurations based on flexural strength, stiffness, strain level, energy absorbed, and density. The results demonstrated substantial improvements in energy absorption of up to 127.8 % and ductility, with strain increases attaining 204.5 %. There was significant variation in strength and stiffness across alternating configurations. The optimum structure was vertically loaded hybrid composites utilizing fine steel mesh in the inner layer (SVI1), providing the most effective balance of durability, resilience, and retention of energy for lightweight, energy-absorbing applications, revealing overall improvement of 34.75 %.