Finite element modelling of defective carbon nanotube reinforced polymer composites

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2019-8
Özel, Coşkun Kağan
Carbon nanotubes (CNTs) attract significant attention being one of the superior engineering materials that possess exceptional material properties. One of the uses of carbon nanotubes is as reinforcements in a polymer matrix to form Carbon Nanotube Reinforced Polymer (CNTRP) composites. CNTRPs are lightweight structures with enhanced mechanical properties due to CNT addition. It is well known that CNTs do not usually exist in perfect structural form. They possess defects such as vacancies or Stone-Wales (SW) defects. These defects have the potential to significantly affect the mechanical properties and thus the mechanical response of the CNT under loading conditions. This study aims to model various defective CNTs with different geometric and structural properties in order to investigate essential mechanical properties more realistically using nano-scale equivalent continuum modelling. Then, CNTRP composites are modelled that contain CNTs with defects. The developed CNTRP composite finite element models are then utilised to bring a more realistic insight into their properties and responses under mechanical load. First part of the study focuses on the investigation of single-walled carbon nanotubes (SWNTs) with Stone-Wales, mono-vacancy, di-vacancy, and combination of these defects. Zigzag and armchair configurations are considered with different diameters for the simulations. Results clearly show that defects may have significant effects on mechanical properties in the form of Young’s modulus, shear modulus and Poisson’s ratio. The second part of the thesis focuses on modelling of defective CNTRPs. The study on CNTRPs are carried out for 5% volume fraction of SWNTs. CNTRPs are modelled via continuum approaches. Results indicate that presence of defects can affect Young’s modulus and Poisson’s ratio adversely depending on diameter and chirality of tubes.

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Citation Formats
C. K. Özel, “Finite element modelling of defective carbon nanotube reinforced polymer composites,” M.S. - Master of Science, Middle East Technical University, 2019.