Check this links https://github.com/jochym/jochym.github.io  and http://jochym.github.io/qe-doc/  i.e. ipython notebook from this page http://nbviewer.ipython.org/github/jochym/qe-doc/blob/master/Elastic_constants.ipynb

The total-energy calculations need to be done carefully because the response to a small (1-2%) strain is small while the total energy itself is a large number. Convergence wrt k points is something to look into as well. 

You can try this:

http://exciting-code.org/elastic

Best Wishes,

Shweta

Thermo_pw package of quantum espresso, is easiest way to calculate elastic constants. It uses the same quantum espresso input format.

https://dalcorso.github.io/thermo_pw/  

DearMegha Goyal

I am using Thermo_pw to calculate the elastic constant, but I faced with some problems. The answer I get was tens of other people's.

Thanks a lot if you can help me.

Best wishes!

Dear Hong Nian Liu ,

What is the value of elastic constant of your compound which other people are getting? your C11 = 2754.1 GPa

Best Wishes! Megha Goyal

Dear Megha Goyal ,

Thank you for your answer, I have fixed this problem. The celldm(1) should use bohr as the unit, but I use the A. Now the C11 = 155GPa.

Best Wishes! Liu