Material Assignment Process in Abaqus

[SKSA]

Hi there,
I am facing some issues when going to implement my abaqus subroutine. I perform the step-1 which is geostatic step. Then I would like to decrease the strength in some portion of material. How I can go with it?
Can I use the subroutine for specific step?
Can I decrease the strength of specific portion and analysis it?

Please give me some idea so that I may proceed with it.

 

[FEA way]

What subroutine ? Abaqus has built-in damage (stiffness degradation) models too.

 

[SKSA]

I am using VUSDFLD for Mohr Coulomb. At first step I want to see the slope is stable anf next step I want to reduce the strength of some portion then I want to see the effect. Is it possible,Sir?

 

[FEA way]

It should be possible to extend the MC model this way. Those old threads can be helpful:

https://www.eng-tips.com/viewthread.cfm?qid=326954

https://www.eng-tips.com/viewthread.cfm?qid=416194

Or you could consider switching to the Drucker-Prager model which can be used with progressive damage and failure models and thus account for stiffness degradation.