I am trying to use FEA with space frame element. I know that for rotating an angle a around the z-axis, the translational displacements of the local and global coordinates are related through the rotation matrix:(adsbygoogle = window.adsbygoogle || []).push({});

[tex]\begin{bmatrix}cos(a) & sin(a) & 0 \\ -sin(a) & cos(a) & 0 \\ 0 & 0 & 1\end{bmatrix}[/tex]

But how about angular displacement (deflection), I thought the rotation matrix for them would be:

[tex]\begin{bmatrix}1 & 0 & 0 \\ 0 & 1 & 0 \\ 0 & 0 & 1\end{bmatrix}[/tex]

But it turns out it is the same with the first rotation matrix (or is it not?). Can anyone give me some hints how to derive or verify this?

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# FEA - Rotation Matrix of Angular Deflection

Can you offer guidance or do you also need help?

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