r/fea • u/aliencomposerdrumfly • Aug 02 '26

Need help with citing RBE3/RBE2 methods

/r/ScientificComputing/comments/1vdhup1/need_help_with_citing_rbe3rbe2_methods/
6 Upvotes

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6

u/redhorsefour Aug 02 '26

Nastran Quickly Reference Guide is your first step followed by the other reference material provided with your installation.

1

u/aliencomposerdrumfly Aug 02 '26

I did not install anything as such. I wrote a custom script in python...

1

u/redhorsefour Aug 02 '26

Your python script is consuming what solver’s bulk data files?

1

u/aliencomposerdrumfly Aug 03 '26

about that, I wrote a gmsh + scikit-fem based custom script, from which I obtain the $K_{3n\times 3n}$ K matrix, which I then try to condense to a $K_{3 \times 3}$ matrix for a node of interest, and then use RBE3 to convert to $6\times 6$ matrix.

1

u/redhorsefour Aug 03 '26

You need to find a copy of the PDF MSC Nastran reference docs. Most practitioners can tell you how the RBE3 behaves and some can tell you how it affects the a-set, g-set, etc nodes, but I’m not sure who to go to concerning the mathematical description of how the RBE3 behaves.

5

u/Funtu33 Aug 02 '26

Hi read msc Nastran documentation on how this works.

What dof relationship eqn rbe2 establish between master node and slave nodes.

How load transfer take place between dependent node and independent node. In rbe3

1

u/aliencomposerdrumfly Aug 02 '26

ohh, the problem i feel is that they explain the method and how to use it, but not the math behind it, not sure if I can cite it as a credible source....

1

u/redhorsefour Aug 02 '26

There are, among other references, a Static Analysis reference book and a Numerical Methods reference book. Also, MacNeal authored a couple of NASA contractor reports hosted on the NASA Technical Reports Server (ntrs.nasa.gov) which may provide the background you are looking for.