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.
The research in this paper entails the design of material systems with tunable energy-absorbing properties. Hollow glass microspheres of different densities are layered using dry powder printing and subsequently sintered to form a cellular structure. The tunability of the bilayer foams is investigated using various combinations of hollow microspheres with different densities and different thickness ratios of the layers. The mechanical responses to quasi-static uniaxial compression of the bilayer foams are also investigated. These bilayer samples show different mechanical responses from uniform samples with a distinctive two-step stress–strain profile that includes a first and second plateau stress. The strain where the second plateau starts can be tuned by adjusting the thickness ratio of the two layers. The resulting tunable stress–strain profile demonstrates tunable energy absorption. The tunability is found to be more significant if the density values of each layer differ largely. For comparison, bilayer samples are fabricated using epoxy at the interface instead of a sintering process and a different mechanical response is shown from a sintered sample with the different stress–strain profile. Designing the layered foams allows tuning of the stress–strain profile, enabling desired energy-absorbing properties which are critical in diverse impact conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.