Impact absorption in auxetic damageable materials

In this work we study the behaviour of elastic and quasi-brittle auxetic metamaterial under impact. Particular reference is made to the use of these structured materials for facial protector devices for sport activities. Impact analyses of a ball over an auxetic and a non- auxetic honeycomb material show the potential benefit of the densification mechanism occurring in the auxetic material below the impacted region. Moreover, when the bulk material is assumed to have a brittle behaviour, the auxetic lattice in compression develops a smaller damage with respect to the honeycomb, non-auxetic lattice. This can be another advantage in impact absorption applications.