I'm trying to simulate a system similar to this one:

http://scienceworld.wolfram.com/physics … asses.html

I can simulate it just fine using 1-D translational elements, but I'm trying to do it in 3D with the multibody tools and I'm having trouble getting it to run. I eventually need to have a 3D system built with these components but this is my first time using Modelica so I'm trying to get a very simplified system to run, hence using 3D tools to solve a 1D problem- eventually it will be 3D.

I have attached my (primitive) stab at making this system.

SingleStrut5.mo

Right now it gives me an error that I have mismatched equations and variables, and I suspect it has something to do with my initial conditions but I'm stumped. Any help would be much appreciated!

Edit: Tried a couple more things. I replaced the frame translation element with a BodyCylinder of the same length, and now I have matched equations and variables. Unfortunately, trying to run it gives me "An independent subset of the model has imbalanced number of equations (1) and variables (0). variables:equations: 1 : 0.0 = 0.0".