Damping characteristics of carbon nanotube reinforced epoxy nanocomposite beams

TLDR: In this paper, a modified Biot model is proposed to simulate the frequency-dependent damping characteristics of CNT reinforced epoxy nanocomposites and implemented into the finite element model for composite beams.

Abstract: In this paper, theoretical and experimental studies are carried out to investigate the damping characteristics of carbon nanotube (CNT) reinforced epoxy nanocomposite beams. A modified Biot model is proposed to simulate the frequency-dependent damping characteristics of CNT reinforced epoxy nanocomposites and implemented into the finite element model for composite beams. The natural frequencies and modal damping ratios of CNT reinforced epoxy beams are predicted using the proposed finite element model. Then, CNT reinforced epoxy beam specimens are fabricated, upon which dynamic mechanical analysis and vibration tests are carried out. Comparison studies between theoretical and experimental results show that modified Biot model proposed here is more accurate than the original one in predicting loss factors of CNT reinforced epoxy nanocomposites. It is revealed that the damping ratios associated with the first three vibration modes of composite beam specimens initially increase and then decrease with the increment of CNT weight ratio. The first order damping ratio with 0.4 wt% CNT reinforcement has the maximum value of 0.591%, which is improved by 41% compared with that of pure epoxy.