Hello all,
I'm trying to analyse an aircraft wing model with Optistruct non-linear statics with "PARAM,LGDISP,1" and "PARAM,FLLWER,1", in order to simulate large displacement efects on the structure, namely wing crushing. No contact or non-linear material curves.
I'm using the following non-linear parameters:
NLPARM 100 10 0.0 25 UPW
NLPCI 100 MRIKS
NLADAPT 101NCUTS 10
Since the model is expected to experience several panel bucklings, i've enabled arc-length methods (MRIKS method seemed to achieve best convergence, in previous similar models).
I've created several continual loadsteps using the "CNTNLSUB" card. Each loadstep increases the load by 5%. I expected that this small gradual increase in load would facilitate the convergence of the model, but in many loadsteps i've noticed that the solver indicated the solution has converged despite it not reaching a load factor of 1.0 .
From the .out file:
Why does the solver decide that it has converged before even reaching half the applied load of the loadstep?
I don't have too many experience debugging non-linear analysis, so any help is greatly appreciated.
