Experimental and Numerical Study on Free Vibration of Multiwall Carbon Nanotube Reinforced Composite Plates

The effects of different percentages of multiwall carbon nanotube (MWCNT) on natural frequencies of polymer composite plates of varying edge-to-thickness ratio, aspect ratio and boundary conditions at ambient temperature are investigated experimentally and numerically. Conventional hand lay-up technique is used to prepare the MWCNT polymer composite plates with different percentages of carbon nanotubes (CNTs) mixed to the polymer. The elastic properties are determined experimentally by conducting uniaxial tensile test in the universal testing machine INSTRON 8862 as per ASTM D-3039. A set of experiments were conducted for the natural frequencies of vibration of MWCNT composite plates using the Bruel and Kjaer Fast Fourier Transform (FFT) analyzer with pulse platform. Detailed parametric studies are carried out to determine the effect of weight fraction of CNTs, aspect ratios, edge-to-thickness ratios and boundary conditions on the natural frequency of composite plates. Numerical solutions were obtained by the commercial finite element method (FEM) package ABAQUS. A simulation model is developed using the same geometrical and material properties determined experimentally from which the frequency responses are obtained. The simulation results are found to be consistent with the experimental ones. The results obtained showed an increase in elastic properties and natural frequencies up to 0.3 wt.% of MWCNT and decrease thereafter for all cases due to agglomeration of CNT in the polymer matrix. The morphology and dispersion of the CNTs in composites at micro level are investigated by using scanning electron microscopy (SEM) to further corroborate the behavior of specimens.