Applying arbitrary rotation boundary conditions

[andrew3]

I am trying to apply rotational boundary conditions for all three rotational DOFs to a rigid plane that is tied to a deformable 3D-solid and am having some issues.

Everything behaves as I expect it to if I apply rotations that are proportional to one another. However, if I apply rotations that are not proportional to one another, the result is not what I anticipate. As an example I have tried to spin a cube about the x-axis 1 full revolution (UR1=2*pi, amplitude is a ramp) while having it wobble about the y-axis (UR2=1, amplitude varies as a coarsely interpolated sine wave, starting and ending at 0). To my surprise, the cube does not end in its original position! I am just trying to understand what is going on in this simple example so that I can use this method to apply experimentally measured boundary conditions to other simulations. The input file is attached.

Thanks for the help,
Andrew

 

[akabarten]

Hi Andrew,

I am not sure is this answer for your question but please take a look into Abaqus documentation:
Abaqus Analysis User's Manual, 1.2.2 Conventions, Finite rotations
Abaqus Analysis User's Manual, 33.3.1 Boundary conditions in Abaqus/Standard and Abaqus/Explicit, Prescribing large rotations

Regards,
Bartosz