Model is not solving when I apply Force but Model is Solving when I apply SPCD, why ?

Yeshwanth_

Hi Everyone,

I'm facing an issue in my model that when I apply Enforced Displacement SPCD, my model is solving and converging, but when I apply Force, my model is not converging and solving. In the initial stage itself, I'm getting cutbacks. I don't know what the issue is, but I doubt in the contact settings. I have given three Frictionless Contacts and one Frictional Contact with the PCONT property. My model is not at all sliding with the force applied (3.5 kN) or my model gets distorted.

Can anyone help me out in solving this issue?

I have attached .out and nl.out files, please let me know if I need to change any contact settings.

solon

Hello,

Force/SPCD:

Please reconsider your boundary conditions (spc, spcd, contacts…) and if the model can stabilize effectively with them. Since without the SPCD the model cannot converge, probably there is instability in the loading direction.

Contacts:

You can consider adding clearance=0 to close all contacts at the beginning of the simulation (regardless of their actual gap distance) and/or add contact stabilization CNTSTB.

Additionally, you can refer to the below article on Nonlinear convergence issues troubleshooting:

https://community.altair.com/discussion/39803/troubleshooting-for-optistruct-nonlinear-convergence-issues