Drucker-Prager Help 1

[mmmbordo643]

Hello,

I am trying to run a powder compaction analysis using Standard and I keep getting the following warnings and error. Can anyone help me out with this or give me a good place to look.


***WARNING: THE STRAIN INCREMENT IS SO LARGE THAT THE PROGRAM WILL NOT ATTEMPT
THE PLASTICITY CALCULATION AT 35 POINTS

***WARNING: THE PLASTICITY/CREEP/CONNECTOR FRICTION ALGORITHM DID NOT CONVERGE
AT 6 POINTS


***NOTE: MATERIAL CALCULATIONS FAILED TO CONVERGE OR WERE NOT ATTEMPTED AT ONE
OR MORE POINTS. CONVERGENCE IS JUDGED UNLIKELY.

***WARNING: CONVERGENCE JUDGED UNLIKELY. INCREMENT WILL BE ATTEMPTED AGAIN
WITH A TIME INCREMENT OF 1.95313E-02


INCREMENT 1 STARTS. ATTEMPT NUMBER 5, TIME INCREMENT 1.953E-02

***WARNING: THE PLASTICITY/CREEP/CONNECTOR FRICTION ALGORITHM DID NOT CONVERGE
AT 1 POINTS


***NOTE: MATERIAL CALCULATIONS FAILED TO CONVERGE OR WERE NOT ATTEMPTED AT ONE
OR MORE POINTS. CONVERGENCE IS JUDGED UNLIKELY.

***WARNING: CONVERGENCE JUDGED UNLIKELY. INCREMENT WILL BE ATTEMPTED AGAIN
WITH A TIME INCREMENT OF 4.88281E-03


***ERROR: TOO MANY ATTEMPTS MADE FOR THIS INCREMENT






Thanks,

Chris

 

[xerf]

Some advice:
-set the NLGEOM on
a.-set the maximum time increment to a small value (say 0.1)
b.-set the initial time increment to a very small value (say 0.01)
c.-set the minimum time increment to a very very small value (say 10^ -10)
-verify to have the loadings applied in a "ramp" manner

If it still does not converge try to reduce the values from a. b. c.
Also you can try to remesh your model.