Hossein Ehteshami - BME, University of Sistan and Balouchestan , Zahedan
Omid Sepahi - phD stident Isfahan University of Technology , Isfahan

Carbon nonatubes (CNTs) possess extraordinary mechanical and also electronic properties , which make them probable building blocks of future high-stiffness materials and molecular nanodevices. The natural strength of the carbon-carbon bond indicates that the Young modulus of carbon of carbon nanotubes (4-5 TPa) might exceed that of other known. Material is the first step towards its use as a structural element for various applications . in practice, structural engineering is applications. In practice, structural element for various applications. In practice, structure engineering is largely base on the theory of elasticity , and design is concerned with stresses below the elastic limit, safe loads being half that of the elastic limit or less. Obviously , for obtaining Young modulus of CNTs , wall thichness of nanotube is necessary information. To date , there is no agreement about the axact value of thickness (h) and corresponding to that about Young modulus (E) of a nanotube . typically h is considered as inter-planar space between graphite layers dg=3.4Å. In this article, effective wall thickness of single walled-carbon nanotube with help of continuum theory was studied. In addition, obtained results with previous work compared and application of continuum theory was overviewed. Obtained results are in good agreement with previous works. Wall thickness and Young modulus of single-walled nanotune are very close to value which Yakobson et al. reported . By fitting in – plane stiffness and flexural rigidity of nanotube with MD simulations, Yakobson and co-workes attained wall thickness. This agreement shows that continuu, model truly can predict wall thichkess of nanotube and obtained results are comparable