Change from MC model to Hss .

Dear Ashraf,

The difference here is the value for the Poisson's ratio being used each time by the constitutive model. 

To explain what happens behind the stage here:

1. A MC material is defined with E = 468000 kPa and v' = 0.3
2. The program computes and stores G, which is defined as G = E / ([2 * (1 + v')]
   In this case, G = 180000 kPa and it is used as a reference value.
3. When switching to HS material the program has stored the value for G = 180000 kPa and to show the value for Eur it needs to convert it back using the formula:
   Eur = G * [2 * (1 + v'_ur)]
   However, on the page with the HS material, you will notice that v'_ur = 0.2
   Therefore, Eur = 432000 kPa instead of E = 468000 kPa that you would expect if v' = v'_ur = 0.3 would have been considered during the conversion.

If you use a Poisson's ratio of 0.2 you will not see any difference when switching from a MC to a HS material.

In general, I would strongly advise you to check the values applied as different properties rely on different parameters for each constitutive model, making the conversion back and forth less straightforward.

I hope that this is clear now.

THANK YOU VERY  MUCH.