Energy absorption and damage assessment of non-hybrid and hybrid fabric epoxy composite laminates: experimental and numerical study

The energy absorption due to low-velocity impact on non-hybrid and hybrid (Kevlar-K, carbon-C, and glass-G) fabric reinforced epoxy composite laminates were studied by conducting standard drop weight tests. The experimental energy absorption results were compared with finite element analysis results. Both values were in good agreement with a maximum variation of about 6%. Kevlar/epoxy (K/K/K) specimen recorded the highest energy absorption (18.67 J) followed by Kevlar specimen sandwiched with glass fabric in the middle layer (K/G/K) (17.24 J). Specimens consisting of glass or carbon layers in the middle, sandwiched by Kevlar layers at the top and bottom (K/G/K and K/C/K) exhibited better energy absorption compared with laminates consisting of all three fabric reinforcements (K/C/G (13.38 J), G/C/K (16.11 J) and C/G/K (16.04 J), respectively). Considering the cost of these composite laminates, K/G/K composite offers 21% reduction in material cost when compared to K/K/K specimen and also offered reasonably enhanced impact resistance and energy absorption as compared to other hybrid composites. Hence, this data may be useful for developing cost effective impact resistant components for defense (protective helmets and body armor) and aerospace (aircraft body components) sectors. The morphological study of the drop weight impact tests revealed that, delamination, fiber breakage, fiber splitting, and matrix cracking are the major damage mechanisms observed in the study. The cost was found to be a critical factor to compare between the different composites.