Optistruct converge problem

Ovunc

Hello,

I am working on the deformation of an engine. The engine is mounted to the ground with 4 bolts. The engine is operating in a hot environment. Both force and thermal loads act on the engine.

I addressed the problem in 2 load steps. In the first load step, I torque the bolts necessary for assembly. In the second load step, I affect the forces coming from torquing, the forces acting on the engine and the forces coming from thermal expansion. For thermal expansion, I gave the same temperature to all components and did not allow heat transfer between the parts.

But the model does not converge. What do you suggest for convergence?

Thank you.

Best Regards,

Ovunc

L3_FULL.out

L3_FULL_nl.out

Adriano_Koga

are you sure you're using the right boundary conditions in your model, specially loadstep #2?

Anyway, from your .out file there's an important note:

NOTE # 412
There exist multiple nonlinear subcases with path-dependent characteristics.
Presently each nonlinear subcase will be treated as a separate new loading.
To make consecutive nonlinear subcases continue the path-dependent solution,
set executive section command CNTNLSUB,YES. Additionally, CNTNLSUB subcase
command may be used to selectively activate nonlinear process continuation.

To create a subsequent loadcase, you should use the CNTNLSUB option, so that the pretension is kept and the loadcase continues.

Other than that, you should try debugging your model.

https://community.altair.com/discussion/33277/tips-tricks-optistruct-nonlinear-analysis