"Too many increments needed to complete the step" problem

[AnkitBhardwaj]

Hi all,

I am working on modelling of an adhesive bonded structure in Abaqus. I have modeled the structures as one single part but partitioned it to assign different properties of adhesive and adherents (concrete). The analysis was being aborted by Abaqus at a load of 80 kN earlier but after lowering the initial increment and minimum increment, it works upto load of 100 kN. But the model is not working further, while the structure is supposed to fail at 200 KN. On the other hand, the model is working well up to 500 kN in linear range and no fail (smeared crack) criterion .

In the failure model, the error shown is "too many attempts".
And the warnings shown are "degree of freedom 5 is not active in this model and can not be restrained", "Degree of freedom 6 is not active in this model and can not be restrained" and "There is zero FORCE everywhere in the model based on the default criterion. please check the value of the average FORCE during the current iteration to verify that the FORCE is small enough to be treated as zero. if not, please use the solution controls to reset the criterion for zero FORCE".

Please help me to understand these error and warnings and suggest some solutions.

Thanking you in advance.

 

[IceBreakerSours]

"Too many attempts.." is not the cause of an error; it is a symptom. In almost all cases, reducing the time increment does not get you anywhere. DoF warning messages simply imply that from the BC manager you chose to restrain DoFs that do not exist at some nodes. For example, nodes on continuum elements do not possess rotational degrees of freedom (4,5, and 6). Finally, as the message implies, force is not get transmitted. Reasons could be many; applying a BC to a fixed part, for example, is not going to allow the part to move and, therefore, transmit the externally applied BC to the rest of the part/assembly. Check your BCs.

Such questions have been answered many times over in this and other groups. Google before you post.

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[bvrm22]

Sometimes it's also the case the maximum number of iterations setting is just too low. Right click your steps, click edit..., Tab incementation and increase the maximum number. But as IceBreakerSours says, if you're experiencing long computation times due to too small time-increments, you should re-check your model first.

grtz
bvrm