Dear all,

I want to calculate mechanical properties (elastic moduli, stiffness constants, poisson's ratio, Lame constants, etc.) of cross linked epoxy polymers using Materials Studio. I've constructed, minimized and equilibrated the system. finally I've performed some data collection runs using NVE ensemble. assumming all these steps done perfectly, now I have both single structure (.xsd) and trajectory (.xtd) files.

I've read the related parts of the online help, and also some complementary materials, and what I've found is briefly as followes:

some, e.g. in Accelrys online help, say that there are 3 methods for calculation of mechanical properties using MD simulations: 1)static, 2)dynamics, and 3)fluctuation formula.

some other say that the propertie can be calculated using: 1)second derivatives, 2)constant stress, and 3)constant strain.

on the other hand, there are apparently 3 options in Accelrys Materials Studio software for calculation of mechanical properties of a 3D priodic system: 1)Discover Analysis(Fluctuations), 2)Discover Analysis(Static), and 3)Forcite Calculations(Mechanical Properties)._if I'm wrong, please let  me know.

All these methods and options made me confused. I have some questions, and would be extremely grateful if someone could help me find the answers:

a) what are the relationships and differences between two categories of methods?

b) which methods are used in Materials Studio, and in which module? in other words, which methods do the obove modules in the software use?

c) which methos are recommended for my purpose?

Thanks in advance.

Regards,

Farzin