Time increment, overclosure Error 1

[mmmbordo643]

I am using the drucker-prager cap model for my elastic plastic analysis. I am compacting a material at 3 mm/s from the initial height of 5 mm to the compacted height of 2mm in 1 second. The nlgeom is on and the half-step residual tolerance is set to 1. I get the following warnings and error:


***WARNING: EXCESSIVE DISTORTION AT A TOTAL OF 330 INTEGRATION POINTS IN SOLID
(CONTINUUM) ELEMENTS


***NOTE: ELEMENTS ARE DISTORTING EXCESSIVELY. CONVERGENCE IS JUDGED UNLIKELY.


***NOTE: SEVERE CONTACT OVERCLOSURES EXIST. CONVERGENCE IS JUDGED UNLIKELY.

***WARNING: CONVERGENCE JUDGED UNLIKELY. INCREMENT WILL BE ATTEMPTED AGAIN
WITH A TIME INCREMENT OF 9.76563E-06


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



any help is greatly appreciated

thanks,
Chris

 

[corus]

You can see the set of elements that have distorted in Viewer but usually this is of no help as the elements never seem to have distorted that much. The problem may lie in the overclosure statement which usually means you haven't set up the contact properly or you had initial overclosure, particularly if you haven't been able to complete a single iteration. Use the *contact controls, *adjust, and don't use reduced integration elements. You could also try a less severe loading to get some kind of a solution to see if the problem still exists or disappears.

corus