creep

I am trying to simulate creep damage in welded components in ABAQUS. I have four different sections in the same model assigned to four different materials. They are weld metal, base metal and Heat affected zones. I have to write a creep subroutine. For all the zones, creep equation is the same , but the parameters or constants change. i want to know how can I assign different parameters for different materials in the fortran source subroutine? what is the variable used for Material 1 , material 2 etc in standard ABAQUS?

Dear All,

I'm trying to do creep analysis of thermoplastic in abaqus. just i want know the what are all the FE input required for creep analysis for abaqus(also how to get those data). Please who are worked on creep requested to share the information and its usefull for everyone.

Thanks and Regards

Ista.

In Computational mechanics, for rate(time) dependent calculations (eg. Creep, plasticity), when we say time step dt, does it mean physical time.

Can I think this way:

I start at time 0 and calculate stress, strain etc  after 1 sec, 2 sec, 3 sec..

Also, what exactly is strain rate? why do some books say ..'when a strain rate is applied'''..I'm confused..dont we just apply displacement or force all the time.