This is intellectual property and I therefore cannot upload the model. This is an illustration of what I have:

In motion analysis I need to simulate the stress on the assembly in red. What I have done:

Added Gravity

Selected the cylinder as a linear motor with a Oscillating distance of 800mm (Stroke)

It does animate correctly but when I go to the “Simulation Setup” it does not allow me to select the assembly in red in order to simulate stresses.

Please help.