PSI - Issue 12

Francesca Curà et al. / Procedia Structural Integrity 12 (2018) 44–51 Author name / StructuralIntegrity Procedia 00 (2018) 000 – 000

47

4

load cell to a screw jack actuated by a gear motor. The screw jack pulls actuated by a gear motor. The screw jack pulls and pushes the spline coupling shaft respect to the fixed hub and the load cell measures the force F needed to perform this operation. The ratio between the force F and the tangential force generated by the torque allows to obtain the coefficient of friction value.

3. Results and discussion

Table 4 resumes all experimental results related to Pin-on-Disk tests. In particular, for each lubricant (Oil 1, Oil 2, Grease) and for each compound (0, 0.5, 2, 5, 10% of GNP) CoF mean values (Mean CoF) of three measures, corresponding Standard Deviations (St. Dev.) and percent difference (%Diff.) respect to the pure lubricant are reported.

Fig. 1. Tribometer apparatus.

Fig. 2. Spline coupling CoF test rig.