Missing of convergnece of corrector iterations

[Anonymous]

Good Morning,

I am trying to run a non-linear analysis under blast loading on a steel frame. However, I am getting the following error message "missing of convergence of corrector iterations".

I run the analysis under static loads and there are no instabilities. After applying the blast (time-history function) I get the above message.

Please can someone help advise why this message may occur?

Many Thanks,

[Anonymous]

We have set up a few THA load cases on different models and keep getting both instability and convergence errors. The static load combinations and modal analysis appear to run ok with one Type 3 instability and one missing eigenvalue, the THA load-case then throws up excessive Type 2 instabilities although there appear to be none in the model that are obvious. The analysis cycles through one iteration and then concludes the error ‘missing of convergence of corrector iterations’ suggesting to either ‘enlarge the DIV parameters’ or to ‘switch on the update matrix on each iteration’.

We have tried increasing the number of iterations of the analysis, switching on the update matrix on each iteration and also adjusting the relative code tolerance for residual forces. As well as looking at different time steps and divisions. None of these modifications seem to make a difference and result in the same errors/warnings.

I note that a successful THA was run on a previous version of this model, the only updates made were to the layout of an internal truss – nothing seems odd with this.

Any assistance on this would be much appreciated.

Thanks

[Rafal.Gaweda]

File please