FATIGUE ON FULL LOCKED COIL ROPE UNDER BENDING IN TRAMWAYS SYSTEMS

摘要

The mechanical behavior of full locked coilropes (46 and 50 mm diameter) under bending in tramwayssystems was studied and the additional tension for the mixingfatigue stress state on the wires was determined. Ropes intension with a 25 percent of the rupture tension load weretested in bending on pulleys with no additional load until350,000 cycles of simple bending. The relation between thepulley diameter to rope diameter was 60 and the length testwas 22.5 times the diameter of the rope. It was found thebeginning of fatigue crack nucleation and initial propagationon the second layer of round wires (with a value of 90 percentof additional tension) while the outside square wires keptunbroken. These results were compared with the behavior ofthe ropes in Mérida-Venezuela tramway which had beenworking for 32 years without slipping until they finally gotbroken or underwent fatigue failure.