convergence issues

[mel08]

Hi,
I'm modelling a structure using a bilinear material model.
At yeild, the tangent modulus is set to 5% of initial modulus. I'm having problems with my solution converging. The force appears to converge, but not the displacement. I am guessing that this is because once my modulus is significantly softer I am starting to get large displacements. I have set nlgeom to on. Is there a way I can remove the displacement as a convergence constraint or any other suggestions for dealing with this.
Thanks in advance,
Mel

 

[jiligeo]

Hi Mel, with “Nlgeom, on” you activate the large deformation but the displacement convergence is still active. Probably the maximum value of plastic strain is more than 15 % in your model. You can increase the criteria with "Cutcontrol , PLSLIMIT, value" command.hope that helps.

Regards
Jalil

 

[mel08]

Thanks Jalil,
yes, in my output i have a note that plastic strain exceeds 5% and then begins bisection. The solution eventually converged, but I think that this cutcontrol will be very helpful!!!
Thanks!!
Mel