Comparison between the fatigue curves of pulleys tests and rollers ones

1. During the fatigue testings performed in laboratory, is well known the different character of stress if one employs pulleys where a rope takes the pulley's curvature, or one employs rolls with a punctual contact and unknown curvature, only valuable by stiffness considerations. For endurance calculations when the rope service involves passings on pulleys and on rolls we must know both the fatigue phenomena by means of the two expressions of fatigue curves upon pulleys and rolls that were deduced by specifically performed tests.

Author: E. Gros Pietro