ABSTRACT
Energy must be dissipated for the composite bollard to stop the ingress of a vehicle. To do so, the bollard must mitigate the impact via deformation and failure of its geometry, undergo bending or stretching, or experience strain hardening or strain rate effects (Lu & Yu 2003). Cellular materials have been identified as a solution to increase the energy absorption of structures, warranting further investigation into their properties. Composite structures such as sandwich panels utilize a deformable core separating two plates. Energy absorption is through plastic deformation to the panel, specifically bending, stretching, and fracture of the plates, and localized core crushing (Lu & Yu 2003). Research performed by Goldsmith & Sackman (1992) identified various configurations of panels under static and dynamic loading. They found that the energy absorption capabilities were improved with increasing core density (Goldsmith & Sackman 1992). Finally, Reid et. al. investigated foam filled sheet metal tubes and found that a foam filled tube had twice the energy absorption capacity than its hollow counterpart (Reid et al. 1986). The addition of foam changed the deformation mode and suppressed long wave effects, improving the tubes stability, with thinner tubes receiving a greater advantage.
