IIT Madras researchers explain reduction of vibrations in Automobiles

The results of the research showing the reduction of vibration during car rides have been recently published in the reputed peer-reviewed international journal Nanoscale Advances. The research will lead to a better understanding of the mechanisms of vibration damping in these types of polymers, which would lead to designs of better vibration dampers in automobiles.

Chennai: Indian Institute of Technology (IIT) Madras researchers working in the field of 'Carbon Nanotube Composites' have yielded promising results that can contribute greatly to reducing the vibration during car rides.

Polymer composites – materials formed by combining polymers with various additives – have been used for a long time in recorded history for various purposes. Many polymers, loaded with various types of reinforcing fillers, are the mainstay of daily use articles, from automobile parts to construction components.

Prof. Prathap Haridoss, Department of Metallurgical and Materials Engineering, IIT Madras, along with his co-scientists and research students at the institute, are working towards developing and testing interesting polymer composites.

The results of this research have been recently published in the reputed peer-reviewed international journal Nanoscale Advances. The paper was co-authored by Dr Anand Joy, Dr Susy Varughese, Dr Anand K. Kanjarla, Dr S. Sankaran and Prof. Prathap Haridoss.

Their research will lead to a better understanding of the mechanisms of vibration damping in these types of polymers, which would, in turn, lead to designs of better vibration dampers in automobiles.

Elaborating on this area of research, Prof. Prathap Haridoss, said, "The outstanding properties of carbon nanotubes (CNTs) – nanometre-sized molecules made of rolled-up sheets of carbon atoms – can tremendously improve mechanical, thermal and electrical properties of polymers. Of the numerous attractive properties of CNT-polymer composites, their vibration damping properties make them useful in aerospace, automobile and construction industries."

His latest research on carbon nanotube-reinforced epoxy polymers has shown that these types of composites have excellent vibration damping characteristics, the nature of which, depends on the structure and morphology of the reinforcing nanotubes.

Prof. Haridoss and his collaborators work with a special class of composites called polymer nanocomposites. The discovery that nanoparticles – particles a hundred thousand times smaller than the thickness of a sheet of paper – can afford extraordinary properties to polymers, is the basis of such composites.

"Carbon nanotube-reinforced polymers combine the viscoelastic properties of the polymer with the interfacial properties of the CNT, resulting in enhanced vibration damping. Thus, CNT loaded polymers can conceivably give you a smoother ride on your car. The team decided to find out why," explained Prof. Haridoss, who works with polymers that have been loaded with Multiwalled CNTs (MWCNT).

The research team used MWCNTs synthesized by different techniques and loaded them into Epoxy polymers. MWCT’s are made of concentric tubes of carbon, and the slide between the layers are believed to damp vibrations. Naturally, the efficacy of damping would depend on the nature of the MWCNTs.

For example, MWCNTs prepared by a process called Plasma Arc discharge Method, are straight and long, while those prepared by Chemical Vapour Deposition are coiled.

As can be imagined, the straight long nanotubes would have better layer slide between walls, and thus better vibration damping effects than the coiled nanotubes. This was exactly what the researchers observed in their work.

Further, Prof. Haridoss added, "In order to visualize the damping effects of the two types of MWCNTs, the researchers performed computational simulation studies. Our simulation studies have shown beyond doubt that the vibration damping properties in MWCNTs arise from the interaction between atoms that constitute the inner and outer tubes rather than the inter-tube frictional energy loss."