Fretting fatigue of seven-wire strands axially loaded in free bending fatigue tests
Free bending fatigue tests of seven wire strands, axially loaded with a constant force, were carried out. These tests showed evidence of fatigue failures resulting from fretting fatigue damage initiated on the line contacts between the king wire and the helical wires. Moreover, almost all the fatigue breaks are located in the bending plane, at the fixed end.
A multi-axial non proportional stress state on the contact surface is calculated over a loading cycle. A way to predict the initiation of fretting fatigue cracks is proposed according to Brown and Miller's critical shear plane concept. The external loading which corresponds to the fatigue tests involves a high cycle fatigue regime. The contact conditions, notably the contact area and the coefficient of friction are modified during the early loading cycles by wear action and they reach a stabilized state. A discussion on an application of a multi-axial fatigue damage criterion related to uni-axial fatigue limit test data in order to predict crack initiation under fretting fatigue conditions is proposed.
Author(s): P. Brevet, D. Siegert
A multi-axial non proportional stress state on the contact surface is calculated over a loading cycle. A way to predict the initiation of fretting fatigue cracks is proposed according to Brown and Miller's critical shear plane concept. The external loading which corresponds to the fatigue tests involves a high cycle fatigue regime. The contact conditions, notably the contact area and the coefficient of friction are modified during the early loading cycles by wear action and they reach a stabilized state. A discussion on an application of a multi-axial fatigue damage criterion related to uni-axial fatigue limit test data in order to predict crack initiation under fretting fatigue conditions is proposed.
Author(s): P. Brevet, D. Siegert