FGM

Dear Mina Rakhshi

Among other possibilities, you can change the properties of every element or you can use the temperature to have graded finite elements. The following paper is more ABAQUS-oriented but explains very well the different options available in all FE commerical packages:

http://link.springer.com/article/10.1007%2Fs10999-014-9265-y

Good luck

Emilio Martínez Pañeda

SIMUMECAMAT Research Group
www.simumecamat.com

Dear Mina Rakhshi

It is very well explained in the paper and references therein (in fact, one of the papers cited uses ANSYS).

You can assign spatially varying properties at integration points by defining properties as a function of temperature and providing the model with an initial temperature distribution that matches the elastic modulus variation desired. The assignment of a zero thermal expansion coefficient then eliminates unwanted thermal strains.

I hope that this is useful for you.

Emilio Martínez Pañeda

SIMUMECAMAT Research Group
www.simumecamat.com

Dear Rakhshi, 

To model a full sphere it is useful in Ansys batch mode programming to use: CS command in order to define your selected nodes or keypoints after that choose a 3D curved element.