Hi,

I am a new user of Material Studio and was trying to make some simple models like finding the Youngs modulus of Al. I took the structure of Al from library and using Build_Symmetry_Supercell I increased the number of atoms to 864. I ran Forcite mechanical properties. At first got very low Youngs modulus (about 3 GPa). Later, I increased the number of atoms to 6912 and now the modulus has increased to 46 GPa. I did another run with 55,296 atoms and this time the modulus is about 400 GPa!! I dont understand what is going on. The actual Youngs modulus of Al is about 69 GPa. Can anyone please tell me how can I get the accurate result? I used universal force field and 'Ultra fine' quality and 'Ewald' for both Electrostatic and Van der walls. Any help is much appreciated. Thanks in advance.

Mohammad Sadat