The ARES-EVF design (patent pending) is based on the original
Meissner concept and elongates the sample within a confined
space by expelling the sample with rotary clamps. Instead of the
rotary clamps, two cylinders are used to wind up the sample; one
cylinder is rotating, the other measuring the force. In order to
wind up the sample equally on both sides, the rotating cylinder
moves on a circular orbit around the force measuring cylinder
while rotating around its own axis at the same time (Figure).
Since the force measuring cylinder is fixed in space it can be
directly coupled with the torque transducer of the ARES. The
full rotation of the mobile cylinder is generated by the ARES
actuator. As such the force measurement is decoupled from all
the moving parts and consequently friction and inertia
contributions are not affecting the material response, namely
the force signal. The ARES transducer measures a torque. The
force at the sample can be easily calculated from the measured
torque divided by the cylinder