• Registered: 2013-10-17
  • Posts: 2

Topic: Too many iterations to converge at first steps

Sir,

    I am working on a model for a dapped end beam 40 feet long that is un symetrically loaded i.e can not take advantage of the symmetry to reduce the model size. This is a research project on dapped end beams funded by PCI organization.

I noticed that the models needs too many iterations to converge even at the first steps ( low material strains). For example the model reaches 14 iterations for the first step and 12 for the second so on...

Is this normal?

What is the problem with this model? Need your input!

I don't mind to send you the model to revise and advise what to do if you like.

Thanks!

Quote Post 1

  • dpryl
  • CC software developer
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  • Registered: 2007-07-13
  • Posts: 1,107

Re: Too many iterations to converge at first steps

Dear amirbotros,
if the analysis needs 12 or 14 iterations for steps that are expected to be within elastic response, it may be a sign of some problem, or just the first microckracks developing without significant influenc on global stiffness.

Look at one of these steps to see if the global response is as expected or not, especially if there is some unexpected damage. Furthemore, check the boundary conditions (are all rigid-body motions blocked, including rotations? are there any unrealistic blockings for example restricting transversal expansion and forcing problematic deformations? any interface or bond with too low strength?, etc.).

If the response is not correct and you can not find the problem source, send us your model along with an explanation + sketches of what you are modelling.

dpryl's Website

Quote Post 2

  • Registered: 2013-10-17
  • Posts: 2

Re: Too many iterations to converge at first steps

sir,

     How can i send you my model? I can send you a drawing of the beam that i am modeling?

Quote Post 3

  • dpryl
  • CC software developer
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  • Registered: 2007-07-13
  • Posts: 1,107

Re: Too many iterations to converge at first steps

Please follow the instructions in ATENA Troubleshooting, 2.1.1 I have a problem not listed here (if you can not find the solution/answer in the rest of the Troubleshooting Manual).

dpryl's Website

Quote Post 4