After changing claddings to panels instabilities (type 3) appear in panel nodes

[Anonymous]

Hello RSA familiy!

I need help with my test model. 

I want to know stresses and deformations in the bars of my  "base structure".

First when I used claddings to apply loads, then everything seemed to be understandable - I got my stresses and deformations what seemed to be correct. 

When I wanted to check how much the thin plate (what is connected by bolts with the beam elements) affects the deflections of the beams and whole structure - then the problems appeared.

I gave to the claddings thickness and by that I changed claddings to panels.

But now I get during the calculations instability warnings about the nodes locating inside the panels. I have tried for testing purpose to add for specific node a support, but during the next calculation I get new instability warning with new node.

I would be very thankful when someone could explain me what I am doing wrong.

Best Regards,

Maarjus

[Rafacascudo · Accepted solution]

It seems that nothing is wrong with your model as node displacements are probably compatible with the structure modelled.

Take a look on webinar 16 on Build your Robot Structural Analysis IQ - YouTube and also on several forum messages about instability type 3.

Also,

1-You have analysis warnings that you should check . Ix=0 probably because you forgot to mark Ix calculation on section definition module. There is also a compatible nodes warning.

2- Mesh size is probably too small . This affects analysis time and displaying of results . Some panels display different mesh pattern .

3- Load DL1 has no loads applied.

[Anonymous]

Thank You! 

Your answer helped to solve the instability problem!

Best Regards!

Maarjus