yes, the best way for this is using variable material.

Zdenek

I'd like to ask you what is the most direct way of modeling a concrete beam that has a strength of 35 MPa during prestressing and 70 MPa after this phase, when a subsequent load will be applied on the same macroelement. Is the variable material the right choice? I'm wondering whether is possible to use two previously defined materials or if it is necessary the use of the variable one.

Thank you very much.