USER FATAL MESSAGE 4658 (NPEND)

[josemanuellodoso]

I am running a SOL 106 analysis and in the .f06 file I get:

USER FATAL MESSAGE 4658 (NPEND)
DIFFICULT GEOMETRY PREVENTS FURTHER COMPUTATIONS FOR ELEMENT WITH ID = 1970001

But this element is ok. This message appears after a 5 bisections without convergence in any step.

 

[nlgyro]

What this means is that element 1970001, under the application of load has a severe deformed shape that makes further computation impossible.

This is an indication that the applied load is too severe for the model to handle, or the no. of load divisions (NINC field on the NLPARM card) is very low.

Your options:

1. Try to decrease the applied load on the structure to say 75% to start with and see if the model converges. If it does examine the results to see if it makes sense.

2. Also to increase the NINC field on the NLPARM card.

 

[josemanuellodoso]

That fatal is solved, it was caused by elements which are bad connected. However, the model still doesn't run.
I am doing 100 steps, and in the first step after 5 bisections due to large incremental rotations, that means with only 0.2%, EPI is 8.4E15. Why the model is not able to start the convergence? Sol 101 and 105 run perfectly, and the results don't show any strange...

 

[nlgyro]

Your EPI is astronomical.I'll have to look into your model to really see what's going on. Any chance you can post it here? or maybe a test model?

 

[josemanuellodoso]

Thanks.

I have solved that problema. It was related with way of simulate a sliding joint, I had a free degree of freedom. Now, at least, the anlysis has started and for 2% of load the solution has converged, but it is a big model and it takes a lot of time.