Study of Free Vibration Characteristics of Carbon Epoxy Based Composite Beams

Abstract

Carbon fibers find their application in lightweight structures due to high strength to weight ratio. Passive damping is proving important for vibration control and dynamic stability in advanced engineering systems like aerospace, automobiles and in ship building industry. In the present investigation, Mechanical properties and free vibration characteristics of woven fabric carbon composites were studied by adding micro rubber alone as reinforcement and combination of micro rubber and nanosilica particles as other reinforcements in epoxy matrix. Carbon composites were prepared with two different epoxy matrices containing 9 wt. % micro rubber particle and 6wt. % nanosilica and 9 wt. % micro rubber particles as another combination. To study the influence of cross sectional shapes on vibration behavior of beams, most widely used structural shapes like I, Box and Channel section were chosen. Beams were fabricated with woven carbon fabric and epoxy resin by hand layup technique by maintaining 40 % fiber volume fraction and 60 % matrix volume fraction for all epoxy combinations. Mechanical behavior of modified carbon composites were studied by conducting tests as prescribed by ASTM standards. Vibration damping behavior was studied by subjecting fabricated beams to Impulse frequency response test under cantilever end boundary conditions. It was found that the hybrid carbon epoxy beams with 6% nanoSilica and 9% Micro Rubber by weight showed better damping performance for successive resonance frequencies. Modal responses of all beams like mode shapes and their corresponding natural frequencies were extracted using MEScopeVES® software and discussed.