Low Velocity Impact Response of Syntactic Foams Reinforced with Varying Volume Fractions of Cenosphere and Rubber Crumb

Syntactic foams reinforced with industrial waste-derived cenospheres and rubber crumb fillers present a promising pathway for developing lightweight, impact-resistant materials. However, a comprehensive comparison of their energy absorption characteristics under low velocity impact (LVI) loading remains underexplored. This study investigates the LVI response of syntactic foams with varying volume fractions (20%, 40%, and 60%) of cenospheres (SFC) and rubber crumb (SFR), benchmarked against neat epoxy (NE). The key findings indicate that rubber crumb-reinforced foams (SFR60) exhibit the highest absorbed energy of 16.75 J at an impact energy of 118.82 J, surpassing the NE (6.46 J), indicating superior impact dissipation. Cenosphere-based foams (SFC60) achieve the highest specific energy absorption (SEA) of 0.0115 Jm³/kg, a 117% improvement over NE (0.0053 Jm³/kg), due to their lower density and increasing filler content from 20% to 60% significantly enhances both absorbed energy and SEA, with cenosphere-reinforced foams exhibiting higher efficiency per unit mass. These findings highlight the performance trade-offs between energy absorption capacity and material efficiency, providing valuable insights for designing sustainable syntactic foams for aerospace, automotive, and protective applications.