Desenvolvimento de dispositivo para testes de fricção fadiga de arames

Abstract

The phenomenon of fatigue friction is present in various engineering equipment, since it is common to have components that are in contact under pressure between surfaces and that suffer small cyclic slips. The process, for example, affects the tension armature wires of submarine umbilicals. The present study aims to develop a device capable of promoting fatigue friction in test specimens of submarine umbilical armor wires. The wire used to make the device was the same as that used as a test specimen, with a diameter of 6 mm, medium carbon content, cold deformed and with a zinc layer deposited on the surface. To create the device, its stress mode was observed and the bending stress corresponding to the effort was calculated, which cannot be greater than the yield stress of the material to avoid accumulating plastic deformations in the device. By comparing the constructed SN curves, it was found that the device was not effective in influencing the fatigue resistance of the material, except at the lowest applied voltage level. Then, through microscopic images, it was found that the damage caused by the device to the test specimens was not enough to overcome the zinc layer of the material. The results indicated that the device caused slight damage that was not enough to promote a decrease in the material's fatigue resistance at most cyclic stress levels.