Viscoelastic and vibrational studies of nano hybrid fibre metal laminates

Abstract

Employment of distinct fibres (glass/carbon etc.) in Fibre Metal Laminates (FMLs) is one way of enhancing the durable life of an FML and its performance under dynamic loads. In the present work, carbon fibre is employed in GLARE (Glass/Aluminium laminated epoxy) to enhance the vibration (natural frequency) and viscoelastic (storage modulus (E′), loss modulus (E″) and Tan δ) properties. Similarly, the influence of 1 wt% of Al₂O₃ (alumina), ZrO₂ (zirconium oxide) and TiO₂ (titanium oxide) nano particles are also studied in hybrid (carbon/glass) FML. The mean particle size of Al₂O₃ (5.1 nm), ZrO₂ (25.3 nm) and TiO₂ (63.2 nm) were estimated using the Scherer equation with the aid of X-ray diffractometer analysis. Hybridisation resulted in a 22%, 10% and 2% increase of natural frequencies from mode 1 to mode 3 and 36.3%, 15% and 13.2% of E′, E″ and Tanδ, respectively, when compared to GLARE (glass fibre reinforced aluminium laminated epoxy). TiO₂-reinforced hybrid FML shows the highest natural frequencies among all nanohybrid FMLs. The results summarise that natural frequencies and viscoelastic properties of nanohybrid FMLs are sensitive to the type of fibre, nano particle reinforcement and its size. A stereo microscope and a scanning electron microscope (SEM) were used to analyse the defects at the interface and the nanoparticle dispersion in the matrix, respectively. Further, a numerical model was developed to perform free vibration analysis, and it was noticed that the results were similar to experimental values.