Dear All, 

I'm now using the Forcite module for some simple simulations. I am going to draw the stress-strain curve of the graphene but I have encountered a few problems here. I greatly hope someone could give me some guidance. Plus: The third question is another question that has nothing to do with this topic, but if someone can help me, I will be very grateful.

1. As we know that the young's modulus of graphene is about 1TPa. However, after doing the geometry optimization and the dynamics (I tried NVE and NVT) tasks to relax the structure, I only got about 180MPa using the mechanical properties part in Forcite module. Here is my question: is there anything wrong with my structure or should I change any parameters to fix the problem?

2.After the failure, I used the StressStrain script from MS2019 and the MakeStrainGetStressV1 script from here in order to draw the stress-strain curve. But in this part, the script kept telling me that the deviation in total energy was greater than the specified maximum. I was really confused in this part and I don't know why because I have alreadly done the geometry optimization and dynamics to minimize the energy. 

3.This one is for another materials: MXene. I am also going to do some research on MXene materials like Ti3C2. In this kind of materials, if I want to make a non-periodic single layer, what should I add in the outermost atom, H or -OH. Also if it possible to calculate by COMPASSII? I read several papers and found that they all used UFF forcefield. Is there any problem with COMPASSII?

There are a lot questions in this topic and I really hope someone could gave me some help on any of it. I have put my complete folder in the attachment, thanks again for helping me.

Best,

Jamie