CBar2 and Rotation

[thecadguy]

Greetings,

I am trying to simulate a linear static analysis on a 4 bar linkage. I am using cbar2 to connect and releasing the proper DOF for rotation. Under lower loads (smaller rotation) everything seems to work okay. When I get to a higher load (larger rotation) the model solves but I am seen distortion and elongation in the animation of the links (Shells).

I read cbar2 is not good for this type of application and am now trying a cbush instead. Can anyone please shed some light on why the links are stretching even though their is low stress on these elements? Is the model just flakey at higher loads and this really is a non linear analysis. I tried running in non linear mode and the connects blow up. Is there another element, setting, or trick that I am missing?

Thanks in advance

The Cad Guy

 

[Tuw]

Hi thecadguy,

I dont understand why you still be okay to apply rotational load if you already release the rotational DOF? Or you should keep your rotational DOF?
Can share your input file?

Regards,
Tuw

 

[ksaw]

Did you check if your elements can handle large displacement?
-Kent

 

[nlgyro]

Use CBEAM's as CBAR's do not posses nonlinear capability, and hence not recommended for nonlinear analysis with large displacements.