A fatigue test specimen was attached to the steel ring as shown in Fig. 3. The steel bolt was subsequently tightened to a
known torque level. The output voltage from the tightened steel ring was recorded and converted to force, thus giving the
force value for each torque level as shown in Fig. 6. Ultimately, no plasticity was observed within the experimental limits.
Thus, two torque levels were selected at 20 Nm and 50 Nm, which are equivalent to clamping loads of 5.6 kN and 12.6 kN,
respectively.