Hi Scott,
I am contacting you regarding the dynamometer test results that you have published. I am using RC scale shocks to do earthquake engineering experiments in buildings.
At the moment, I am testing traxxas GTR shocks in a setup similar to the dynamometer you have shown in your report. I have an electromagnetic shaker displacing the shock piston in a sinusoidal fashion. I have a load cell connected in series with the shock to record force, and the piston motion is also being recorded.
Unfortunately, I was unable to get any linear response from the shocks and there always seems to be lag between the force I am recording, and the velocity of the piston. I have even gone to the extent of testing the damper with no cap (open to air) but I still see this lag.
I am wondering whether you had to do any post processing of your force traces to capture the linear damper trends you show. I would really appreciate any advice you may have on this.