Bending stress on ropes running over roller assemblies

Owing to their bending stiffness ropes do not fit closely to rollers. According to formulas of lsaachsen, the magnitude of bending stresses appearing on the rope under the roller is independent of the wire diameter of the rope as long as it does not fit closely. The decay of the bending stress along the rope does, however, depends on the bending rigidity of the rope. From this it follows that the behaviour of the pulsating bending stresses in the rope along a roller assembly depends on the rigidity of the rope, and so influences the lifetime of the rope. The above relationships are being investigated theoretically as weil as in quasi-static tests. This investigation is considering models without friction as well as ropes affected by friction with various stiffnesses. To investigate the relationship between bending rigidity of a rope and its endurance fatigue tests are being carried out.

Author(s): G. Oplatka & M. Roth