I've run into an interesting situation today. I am using a +XROD to give me a directional anchor in a piping system. That worked fine.

Then, I added friction to Y supports in the model to make sure my offset legs would actually slide and give me the flexibility I expect.

Now, the friction supports seem reasonable, but the +xrod has gone wacky generating an infinite number in the x direction and very large numbers in the other two, just in the sustained case. To top it off, the loads are not being resisted by other restraints in the model, in that the numbers don't balance out.

I changed the xrod to an x and it works fine, giving me an x force in line with my expectations.

Is there something about nonlinearity that makes fricion and rod hangers incompatible?
Edward L. Klein
Pipe Stress Engineer

All the world is a Spring