Line and point lubricated contacts are investigated under steady-state and transient conditions with an experimental rig employed in previous studies. New data acquisition and signal processing programmes are developed to record and filter the experimental results under transient conditions. Tests are carried out by varying simultaneously the speeds of both lubricated elements (a spherical or a cylindrical specimen and a disc) in order to maintain the slide-to-roll ratio constant. With the experimental apparatus used, encouraging results are obtained thanks to the new methodology developed. In particular the arising of friction loops with increasing magnitude by increasing the frequency of the sinusoidal speed variation is found, in agreement with some literature results. The results obtained with the spherical specimen, working mainly in full lubrication regime, show friction loops present at low but not at high values of the slide-to-roll ratio, while the ones carried out by the cylindrical specimen show always a presence of loops under mixed lubrication conditions.
Friction investigation under constant and variable speed conditions
BASSANI, ROBERTO;CIULLI, ENRICO
2004-01-01
Abstract
Line and point lubricated contacts are investigated under steady-state and transient conditions with an experimental rig employed in previous studies. New data acquisition and signal processing programmes are developed to record and filter the experimental results under transient conditions. Tests are carried out by varying simultaneously the speeds of both lubricated elements (a spherical or a cylindrical specimen and a disc) in order to maintain the slide-to-roll ratio constant. With the experimental apparatus used, encouraging results are obtained thanks to the new methodology developed. In particular the arising of friction loops with increasing magnitude by increasing the frequency of the sinusoidal speed variation is found, in agreement with some literature results. The results obtained with the spherical specimen, working mainly in full lubrication regime, show friction loops present at low but not at high values of the slide-to-roll ratio, while the ones carried out by the cylindrical specimen show always a presence of loops under mixed lubrication conditions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
