The fixed Surface is the casing's base which I assigned it a fixed support.

also the material I have for the casing you mean ? it is phenolic resin from the ANSYS library.

As I dont have the plasticity values for the phenolic resin available so I  have calculated an estimate based on the values used in here

for the phenolic resin in the plot of number 1

I am not entirely sure of which plasticity type to use from the Engineering library 

could you please support me on that