Low velocity impact performance of 3D auxetic composites embedded with re-entrant triangle inclusions

This paper reports the low-velocity impact performance of 3D auxetic composite embedded with re-entrant triangle inclusions by both experiments and finite element (FE) simulations. Both auxetic and non-auxetic samples were manufactured by embedding inclusions made from carbon fiber/epoxy laminates into silicone rubber matrix. The pure silicone rubber was also manufactured for comparison. All samples were subjected to low-velocity impact with an impact energy of 147 J and an impact speed of 5.42 m/s and their impact load-time and energy-time curves were compared between the experimental results and FE simulation. The impact performances under different impact energies from 60 to 120 J were further investigated based on the validated FE models. The results show that the auxetic composites show better energy absorption capacity and impact resistance than non-auxetic composites with the same number of inclusions at all energy levels. More inclusions can result in better impact resistance of auxetic composites when the impact energy is under 120 J. The auxetic composites possess 10% higher crash efficiency than non-auxetic samples. The embedding of inclusions leads to easier damage of the composite under impact energy of 147 J. The research provides a better understanding on the impact performance of auxetic composites made from random inclusions.