Bilayer Glass Foams with Tunable Energy Absorption via Localized Void Clusters

Abstract

The research in this article entails the design of materials systems and tunable energy absorbing properties respond to a range of energy absorption needs in different impact conditions. Tunable energy absorption of bilayer cellular foams is investigated using hollow glass spheres with different wall thickness and densities. Co‐cured bilayer foams are prepared through sintering of the spheres, and their microstructures and mechanical responses to quasistatic uniaxial compression are investigated. Co‐cured system exploits localized voids density (>50 μm) locally at the interface which is induced via different shrinkage rate of spheres, leveraging tunable energy absorptions. Mechanical testing shows that the voids at the interface lead in the sequential collapse of the layers, resulting in a distinctive two‐step stress–strain profile. For comparison, bilayer samples are fabricated using epoxy. These samples show a different mechanical response from the co‐cured sample by not showing the two‐step stress–strain. The co‐cured samples exhibit 14.8% more specific energy absorption than epoxy bonded samples. The results suggest that co‐cured samples can limit impact stress and achieve a higher energy absorption capacity than epoxy bonded samples. The manufacturing concept and system design expand the capabilities of cellular foams, yielding desired energy absorbing properties in a diverse range of applications.