QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Feng on June 15, 2010, 07:57

Title: How to calculate Young's modulus of CNT
Post by: Feng on June 15, 2010, 07:57

Hi all,

Any suggestions how to use ATK to calculate the Young's modulus of CNT? Thank you.

Title: Re: How to calculate Young's modulus of CNT
Post by: zh on June 16, 2010, 02:50

A simple way:

1. Calculate the total energies(E) of CNT as a function of the periodic length (l);
2. According to the relationship between the Young's modulus and the total energy ([tex]Y \propto \partial^2E/\partial l^2[/tex]), do a quadratic polynomial fit of the data obtained in the 1st step.
[tex]Y= \frac{1}{l_{eq}A}\frac{d^2E}{dl^2} [/tex], where [tex]l_{eq}[/tex] is the periodic length of CNT at equilibrium state, and [tex]A[/tex] is the the area of cross section of CNT.

Title: Re: How to calculate Young's modulus of CNT
Post by: Feng on June 16, 2010, 06:27

Thank you very much. I will try it.

Title: Re: How to calculate Young's modulus of CNT
Post by: Anders Blom on June 16, 2010, 13:31

One thing you will note when checking the literature on this topic is that the definition of the "cross section area" is rather arbitrary for a nanotube, leading to results that differ quite a lot.