PSI - Issue 78

Virginio Quaglini et al. / Procedia Structural Integrity 78 (2026) 105–112

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always occurred regardless of the exposure duration. For this reason, the friction coefficient in tests at – 20 °C is systematically lower compared to the other cases. However, in the case of exposure at 0 °C, ice formation is strongly influenced by the duration of exposure. After 24 hours of exposure, µ dyn is usually observed to be lower than in the reference test at 20 °C, indicating ice formation. In contrast, for exposures of 3 and 12 hours, the values of µ dyn reveal that the exposure time is not sufficient for the formation of the ice layer on the sliding surfaces.

40MPa, 250 mm/s

60MPa, 250 mm/s

80MPa, 250 mm/s

550

550

550

-400

400

-400

400

-400

400

Force (kN)

-550

-550

-550

Displacement (mm) 60MPa, 500 mm/s

40MPa, 500 mm/s

80MPa, 500 mm/s

550

550

550

-400

400

-400

400

-400

400

Force (kN)

-550

-550

-550

Displacement (mm) 60MPa, 750 mm/s

40MPa, 750 mm/s

80MPa, 750 mm/s

550

550

550

-400

400

-400

400

-400

400

Force (kN)

-550

-550

-550

Displacement (mm)

20°C 0°C -20°C

Fig. 7. Comparison of force-displacement loops obtained from tests after exposure to low or very low temperature for 24 hours with the corresponding reference loops (tests after exposure to 20 °C).