New Method to Determine Properties of Nanocomposites Reinforced by Carbon Nanotubes

A group of specialists at Iran University of Science and Technology introduced a new method for determining properties of nanocomposites reinforced by carbon nanotubes.



Dr. Roham Rafi'ee, one of the project researchers, mentioned the aim of this study as prediction of mechanical properties (elastic modulus and Poisson coefficient) of polymeric composites reinforced by carbon nanotubes.



Elaborating on the results of this study, he told the news service of the INIC, "Based to the research results, direct use of micromechanics rules for prediction of nanotubes containing nanocomposites isn't right and, instead, multiscale method should be applied."



Noting that given the nature of carbon nanotubes, appropriate modeling should be done according to a random method and using definite methods yields results far from the reality, he reiterated, "It was revealed by analyses that it's possible to use carbon nanotubes length and volume fraction average values instead of their random values. Other variables like different directions of carbon nanotube orientation, indirect shape, bulk accumulation, and uneven dispersion of carbon nanotube in physical environment should be necessarily considered in the modeling. It is notable that the simulation results show very good agreement with experimental observations made by the others."



At microscale, a multiscale finite element modeling which simulates nanotube as a molecular reticular structure at nanoscale and surrounding resin as a continuum at microscale was applied. Contrary to the previous studies, the idea of equivalent single string which is a substitute for carbon nanotube and interphase was used instead of direct use of micromechanics rules.



Mechanical properties of equivalent single string were calculated on the basis of the mentioned modeling which implies side isotope behavior for equivalent single string. The effect of carbon nanotube length on load transfer from resin to carbon nanotube phenomenon was also investigated.



Considering the uncertainties associated with the problem, multiscale modeling was made randomly contrary to the previous studies. Parameters such as different directions of carbon nanotube orientation, indirect shape, bulk accumulation, and uneven dispersion of carbon nanotube in physical environment were randomly simulated.



The details of the present research are published in Mechanics of Composite Materials, in press, 2010; Composite Structures, volume 92, pages 647-652, 2010; Material and Design, volume 790-795, 2010; Mechanics Research Communications, volume 37, pages 235-240, 2010; Composite Structures, 2010.

Reference: http://nanopatentsandinnovations.blogspot.com/2010/05/new-method-to-determine-properties-of.html