• Registered: 2009-04-23
  • Posts: 7

Topic: validation parameter in atena

Hi, I'm Nico from Indonesia
I would like to know how do we know that a loaded model has reached it's maximum capacity or the model has finished the step of loading as done in realistic laboratory until it's maximum capacity? What parameters or signals do we use in atena? Is it zero jacobian? or when there's warning saying "the convergence criteria is not satisfied"?, or anything else?
what will happen if the convergence criteria is not satisfied? what should we do?
how do we know that our model & the results is valid enough?

regards,
Nico

Quote Post 1

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

Re: validation parameter in atena

Hello Nico,
first of all, please remember that to calculate peak load, it is necessary to use either deformation loading with the Newton-Raphson method, or force loading with Arc-Length (the peak can not be reasonably detected when using force loading with Newton-Raphson).

Then, it should be considered as failure when
- the analysis stops due to conditional break criteria or floating point exception or zero or negative jacobian
or
- there are several not converged steps with large errors in a row (typically, 2% error are not a problem, but 10% are)

Of course it makes sense to change the step length and/or the max. number of iterations to see if it is not just a plain numerical issue.
And one should always check the material data and mesh before drawing any conclusions.

dpryl's Website

Quote Post 2