Autodesk Robot Structural Analysis

[#1]

normally, just use the spreader on two sides, it will be stable for regular shaped geometry.  

[#2]

we are not supposed to use spreader bars, but we have added a support in one of the corner were we have cross checked RX, RY and RZ. This worked with the instabilty in node 52

[#3]

Mortel09 ,No instabilities on your original model if you use the multi-threaded solver.

[#4]

the multi-threaded solver? I added a support in on of the corner so hold the rotation (RX, RY and RZ), will this be wrong to do?

[#5]

My opinion is that if you have an instability in a model, using multi threaded to avoid it is un-conservative and not recommended.  The model should run fine on automatic before switching to multi thread. 

[#6]

Multithreaded solver may not report instabilities that's why it is recommended to find all model instabilities (esspecially of type 1 and 2) using different solvers.

[#7]

Iam not sure what to do, I attached the file, when you hit calculations you get a warning of instability in node 52. What should i do?

[#8]

it's type 3, so may just be large differernce in stiffness.  

[#9]

Okei, thanks alot guys. The both of you have been really helpfull. I appreciate your help.

[#10]

Please check the displacements and rotations for case 1 (self-weight) before ignoring the reported instability.