Vibration Behavior of Syntactic Foam Core Sandwich Beam Using Natural Fiber Composite Face Sheets

Sandwich composites with lightweight core find applications in marine, wind energy, aerospace and civil engineering structures due to their low specific weights. Syntactic foams which can be a lightweight core represent two-component composite material system where hollow spheres are embedded into the matrix resin to form closed cell foams wherein closed porosity is present in the microstructure. In this work, the free vibration behavior of sandwich beam made up of different natural fiber reinforced composite face sheets and a syntactic foam core is investigated numerically and experimentally. Here three different natural fibers viz Sisal fiber, Jute fiber and Flax fiber reinforced with epoxy resin are used as top and bottom face sheets of the sandwich beam, while fly ash cenosphere of grade CIL-150 mixed with epoxy resin is used as syntactic foam core. In the numerical approach, natural frequencies and corresponding mode shapes are determined using ANSYS software while in the experimental approach, the frequencies have been determined using Impact hammer testing. The numerical results are then compared with experimental results for the purpose of validation. Finally, the effect of filler volume fraction in the core and type of natural fiber in the face sheets, on the free vibration characteristics of the sandwich beam are investigated.