Characterization and modeling of compression behavior of syntactic foam-filled honeycombs

Processing and compression behavior of lightweight syntactic foam-filled aluminum honeycomb composites is presented. Different foam-filled honeycomb composites are prepared by varying the volume fraction of microballoons in the syntactic epoxy foam while keeping the volume fraction of the metallic network the same. Uniaxial compression tests are then carried out on syntactic foam and foam-filled honeycomb composites. The latter shows improvement in elastic modulus and plateau stress values by 26-31% and 36-39% when compared to the syntactic foam with the same volume fraction of microballoons. The maximum increase in energy absorption for syntactic foam-filled honeycomb composite is found to be approximately 48%. The compression response and stress-strain characteristics of the foam-filled honeycombs are also examined relative to a 3D variant, namely, an interpenetrating aluminum-syntactic foam composite. Elasto-plastic finite element models are developed to simulate experiments performed on syntactic foam-filled honeycomb composite. The numerical model based on stress-strain responses of the constituents of the composite is shown to successfully capture the overall behavior.