Study of method utilizing fatigue life data on two competing fracture modes
Kaneko Makoto; Nakamura Takashi; Noguchi Toru
Abstract:Many high strength materials, including high strength steels and high strength titanium alloys, show the complex characteristics of fatigue life distribution in the high cycle region. It is caused by the two competing fracture modes, fractures from surface and from interior of the specimen. A method to describe such a complex fatigue life data was proposed based on the competing risk model. The characteristics of fatigue life distributions and S-N relations of each mode were successfully separated and extracted from whole data. These separated data was analyzed and the complex fatigue life distributions was well described by the competing-risk model. The method is helpful to understand the fatigue mechanisms because the fatigue life distribution of different two modes results from and reflects the fatigue mechanism of each mode. Key Words:fatigue, fatigue life distribution, statistical treatment, competing-risk model, fatigue mode, high strength material, high cycle fatigue