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Displacement Increment for contact is too big - warning in contact problem

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redwanamit034

Mechanical
Mar 10, 2013
19
I am making a coupled temperature-electrical-structural model for Spark Plasma Sintering. I have used abaqus standard.

The model worked for simple geometry involving only 3 parts (2 punch and die), but it is not converging for my original model which has 2 punch, sample, die, 4 spacers.
I used SI units and applied a pressure of 5 MPa and surface current at the top of upper spacer.
I included thermal and electrical contact conductance values for all the contacts. Almost 30000 Q3D8 elements are used ( A 8-node brick, trilinear displacement, electric potential and temperature)

I think the problem is with the contacts since all the warnings are related to contact. The warning says- Displacement Increment for contact is too big and also in the message file it says NUMERICAL SINGULARITY WHEN PROCESSING NODE UPPER PUNCH-1.1 D.O.F. 3 RATIO = 5.59991E+09. there are some other similar type of singularity message for nodes.

441 SEVERE DISCONTINUITIES OCCURRED DURING THIS ITERATION.
441 POINTS CHANGED FROM OPEN TO CLOSED



The error that I am getting is -

Too many attempts made for this increment

The warnings are

1. Displacement increment for contact is too big

.2. SURFACE INTERACTION "interaction name", ASSOCIATED WITH ONE OR MORE CONTACT PAIRS WITH SURFACES HAVING UNDERLYING ELEMENTS WITH ELECTRICAL, TEMPERATURE, AND DISPLACEMENT DEGREES OF FREEDOM, DOES NOT HAVE ANY ELECTRICAL INTERACTION DEFINED. NO ELECTRICAL INTERACTION WILL OCCUR.

3.The request for mises output will be replaced by a request for s output

4.Strain output request le is not valid for some elements in this analysis. This request is switched to the strain measure, e.

5.10 elements are distorted. Either the isoparametric angles are out of the suggested limits or the triangular or tetrahedral quality measure is bad.




Can anyone help me ?

I have attached the input file and message file here
 
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