Vibration damping is proving important for improved vibration and noise control, dynamic stability, fatigue, and impact resistance in advanced engineering systems. In the present work, the effect of natural rubber particle inclusions on the mechanical and damping properties of epoxy-filled glass fibre composites is investigated. Test specimens are fabricated with inclusion of natural rubber particles of different sizes and tested for tensile strength, tensile modulus, flexural strength, and flexural modulus. These mechanical properties are influenced by the size of the rubber particle inclusions. Vibration tests are carried out and damping ratio is calculated. It is observed that damping ratio varies with inclusion of natural rubber particles and that 0.25 mm particle inclusions improve damping better than other selected particle sizes without greatly affecting the stiffness in the case of cantilever beams and fixed free plates.

Conventional materials are being replaced in the field of engineering by composite materials, due to their tailorable properties and high specific properties. These materials are extensively used in structural applications. Damping is one of the important properties of the materials used in structures, and needs to be enhanced in order to reduce structural vibrations. In the present work, the improvement of the material damping of glass fabric epoxy composites with particle rubber inclusions is studied. The effect of particle size on the damping and stiffness parameters at different frequencies and temperatures is studied experimentally. Considerable enhancement in damping without significant reduction in stiffness is observed at lower particle sizes. The damping property in both bending and shear modes is more with 0.254 mm rubber particle inclusions among the selected sizes. A lower reduction in stiffness is observed with the inclusion of lower particle sizes (0.254 mm and 0.09 mm) when compared with higher particle sizes. An ANN-based prediction model is developed to predict these properties for a given frequency/temperature and particle size. The predicted values are very close to the experimental values with an maximum error of 5%.

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The main focus of this work is to improve the mechanical, wear and fatigue behaviours of polyoxymethylene (POM) by reinforcing with carbon nanotubes (CNTs). To improve compatibility between CNTs and POM, the surface of the CNTs was modified by various methods of functionalization like carboxylation, silanation, carbonylation and amination. The functionalized CNTs were characterized by Fourier transform infrared spectroscopy to confirm the different functional groups attached to the surface. POM/CNT nanocomposites were developed with functionalized CNTs in different concentrations varying from 0.25 to 2 wt%. Nanocomposites with 1 wt% of silanated CNTs resulted in maximum improvement of tensile, flexural and impact properties. Furthermore, experimental results on fatigue and dry sliding wear tests revealed that the fatigue strength, specific wear rate and friction coefficient are sensitive to functionalization and concentration of CNTs.

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