Effects of Partially Filled EPS Foam on Compressive Behavior of Aluminum Hexagonal Honeycombs

This study investigates the compressive behavior of aluminum honeycombs partially filled with expanded polystyrene (EPS) foam, emphasizing the effects of filler area fractions and vertex contact locations on energy absorption and crush characteristics. Axial quasi-static compression tests evaluated energy absorption, mean crush force, specific energy absorption, and crush force efficiency. Results revealed that partially filled honeycombs significantly enhance energy absorption and mean crush force compared to their unfilled counterparts. However, higher filler area fractions increased mass, reducing specific energy absorption. Circular fillers exhibited lower energy absorption than hexagonal fillers due to their larger contact radius, which reduces stress concentration. The interaction between cell walls and fillers influenced densification strain, with wall-midpoint vertex contacts increasing peak force by reinforcing walls, while corner contacts reduced peak force but improved crush force efficiency. These findings underscore the potential of optimized, partially filled honeycombs for lightweight, energy-absorbing applications, particularly in automotive engineering.