We found an interesting article, wriiten by an Airbus collaborator about energy absorbing barriers in air planes. Especially the impact of birds is dangerous and for that reason, the air plane needs protection with all kind of energy absorbing barriers. These barries should be lightweight but still efficient.
The article also shows the load deformation curve of the perfect kinetic energy absorber. This curve is typcial for foams and indeed also for cellular glass when the compressive strength measurement is done without capping. Indeed, the typical peak at the beginning of the flat part is absent for foams but not for honeycumbs.
The article shows also a graph with the specific kinetic absorption of foams, which do and do not comply with what is needed. The typical foams of polyurethane, polyisocianate and polyethylene do not comply, even at densities of 100 kg/m³. But on the other hand, GLAPOR cellular glass reaches 2000 kPa compressive strength with 140 kg/m³ density. In that case, we have a specific kinetic energy absorption of at least 8 kJ/kg, which is close below the well known (combustible) foams for these applications. Today, PVC-foam and PMI foams have taken this market but when non-combustibility becomes an issue, GLAPOR cellular glass is a good candidate.