Font Size: a A A

Stochastic Multi-scale Characterization Of Mechanical Properties Of CNT/Polymer Composites

Posted on:2016-12-16Degree:MasterType:Thesis
Country:ChinaCandidate:L L AiFull Text:PDF
GTID:2180330479989133Subject:Engineering Mechanics
Abstract/Summary:PDF Full Text Request
With the rapid development of nanotechnology, nano materials making more and more extensive and profound influence for the human production and the way of life. As the outstanding delegate of carbon nano materials, CNT/polymer(CNTRP) composites is becoming one of the most active areas in the contemporary scientific research.The thesis proposes a stochastic multi-scale method and reports a three-step modeling approach(nano, micro and meso scale)to predict the effective mechanical properties of polymeric nano composites modified with single walled carbon nanotube(SWNT) and quantify the correlated key-input parameters influencing the mechanical properties of CNTRP.(1) Setting up the nano scale model of CNT with ANSYS. By establishing a linkage between structural mechanics and molecular mechanics witch based on the theory of molecular structural mechanics, the sectional property parameters of these beam members are obtained. With increasing tube diameter, the Youngs moduli of carbon nanotubes increase monotonically and approach the Youngs modulus of graphite.(2) The nano-heterostructures of the nanocomposites were represented by 3-D nano-scale cylindrical prismatic representative volume elements(RVEs). Each RVE contained a long or a short carbon nanotube(CNT) and consisted of three phases, i.e., CNT, matrix, and interphase. The effects of the volume fraction of CNTs on the mechanical properties of the RVEs were studied.(3) Creating a stochastic lattice modeling,meso-scale nanocomposites were represented by a 3-D micro-scale unit cell which was discretized into cubic elements. Using Monte Carlo method, each element was assigned the averaged mechanical properties of the RVEs with random material parameters.(4)The overall effective mechanical properties of the CNTRP were predicted by a tensile test on the unit cell. The modeling results by this proposed approach was compared with and validated by the experimental data of the SWNT modified epoxy nanocomposites and in a good agreement with published experimental observations. And then, the CNTS volume fraction, element number, various distribution and dispersion parameters are taken into account.
Keywords/Search Tags:Carbon nanotubes, Polymer-matrix composite, Mechanical properties, Multi-scale modeling, Monte Carlo methods, Stochastic lattice modeling
PDF Full Text Request
Related items