Fatigue "inner" hydraulic test

Best name I could come up with at the time...

The idea came to me when I was cycling up a tall hill, needing exercise and time-out.

For fatigue-testing, that
"the hydraulic cylinder is always bigger than the sample you are trying to test"

• has always meant a machine with a frame and parts distributed along a central axis, dwarfing the size of the sample it's testing
• also means the sample will always fit *inside* the hydraulic cylinder which is testing it

Click on displayed drawing to get full-sized presentation:

Using maximum 200Bar (20MPa) hydraulic pressure of a "hydraulic power pack", calculations suggest 190Tonnes-force test would be about 400mm wide and about that tall.

If the hydraulic actuation were servo-hydraulic, which is convenient to do with "catalog" equipment and gives accurate pressure control - but is power-hungry through discarding all pressure energy at each cycle, my very approximate some-idea estimate of power required at the hydraulic power pack motor - 80kW?
Most of that goes to elastically stretching and flexing the parts of the rig illustrated. Very few percent go to loading the sample.
However, the rig would perform very favourably compared to "servo-hydraulic fatigue testing machines".

(R. Smith, 19May2021)