Experimental investigation of compressive behavior and vibration properties of layered hybrid foam formed by aluminum foam/EPS-filled syntactic foam

Hybrid foams are a type of composite material created by combining two foam materials. They are preferred in many applications due to their lightweight, high strength, and ability to absorb more energy. In this research, a new hybrid foam was designed for use in sandwich cores of structural materials. The hybrid foam was formed by combining closed-cell aluminum foam and expanded polystyrene (EPS)-filled syntactic foam. The EPS-filled syntactic foams were produced with the conventional mold casting technique. Uniaxial compressive behaviors (0.5 mm/min) of layered hybrid foams consisting of EPS-filled syntactic foam with three different densities and closed-cell aluminum foam were investigated experimentally and compared with conventional single-foamed materials. These results exhibited that in general, layered hybrid foams outperform conventional single-foamed materials in terms of compressive strength. Moreover, the natural frequency and damping ratio of the layered hybrid foams were investigated by vibration tests under clamped-free and free-free boundary conditions and compared to conventional single-foamed materials. It was established that the vibration damping capacity of the layered hybrid foams improved compared to the closed-cell aluminum foam. Additionally, the microstructure of the conventional single-foamed materials was examined by SEM. In the outcome of the research, the experimental results showed that layered hybrid foam provides an opportunity to design lightweight cellular materials with effective mechanical properties.