Abstract
This paper proposes a laser microscopic in-situ observation method for fretting fatigue processes and shows the results of the observation of wear processes and crack initiation processes. In particular, the authors produced a new clamping method in attaching a proving ring which are necessary for the laser microscopic observation because non-uniform contact condition and steps on the interface between the specimen and the contact pads concealed wearing situations in the case of using conventional clamping method. The new method improved contact condition and reduced the height of the steps and the new method led to initiate an inclined crack whose direction was almost perpendicular to the direction of maximum principal stress. The result of observation revealed that the distance of the position of a top of wear powders from the outer edge of contact pad rapidly increased in the early period of a fretting fatigue life and became a saturated state in the 50% of the FF life. The crack initiation occurred in the vicinity of the maximum wearing region before the wear position had saturated.
