Free Vibration Test for Damping Characteristics of Hybrid Polyester Matrix Composite with Carbon Particles

In this research aims to study the damping characteristics of hybrid polymer composite, which can be used in engineering structures and in many other applications. Hybrid composites are namely Glass fiber and carbon filler reinforced with polyester and epoxy matrix have been prepared by vacuum bag molding fabrication technique. Then the free vibration test were conducted using FFT analyzer with Lab VIEW software. The damping ratio and natural frequency were investigated for fabricated composites. Then through ANSYS, the mode shapes and natural frequencies were determined and the results were compared with experimental results. The damping ratio increases with increased volume fractions of E-glass fibers for both the types of polymer composites. Vibrations are concerned to large structures such as aircraft, as well as small structures such as electronic equipments.

Improvement in Elastic Modulus of MWCNT/Epoxy Nanocomposites

The effect of multi-walled carbon nanotubes (MWCNT) on the elastic modulus of MWCNT/epoxy nanocomposites was investigated. Carboxylic acid-functionalized MWCNTS (MWCNT-COOH) were obtained by oxidation pristine MWCNTs via sonication in sulfuric-nitric acid. Epoxy-based nanocomposites reinforced with MWCNTs with and without functionalization were prepared. In this work, the elastic modulus of MWCNT reinforced nanocomposite was determined by free vibration test. Experimental results showed that functionalized MWCNTs improved the dispersion of MWCNTs in epoxy matrix leading to the enhancement of elastic modulus compared to those containing MWCNTs without functionalization. Nanocomposites prepared with 1 wt % of MWCNT-COOH exhibited 44 % increase in Young’s modulus.