RETROSPECT AND PROSPECT OF VERY HIGH CYCLE FATIGUE

High cycle fatigue is the most common reasons for failure of components and structures Most of the fatigue tests were accomplished below ten to hundreds millions of cycles in literature However, railway wheels and rails, offshore structures, bridges, etc , have to endure fatigue loads up to ten billion cycles without failure Very high cycle fatigue (VHCF) is the study of fatigue failure behaviors of materials and structures at and beyond hundreds millions of cycles Even in some ferrous materials, which were assumed to have a fatigue limit, very high cycle fatigue failures are detected Till now, there are few of fatigue tests, failure analysis and mechanisms of VHCF fatigue, compared with the abundant result on LCF and HCF regime This paper summarizes works of VHCF fatigue in recent years, such as the observations on fish eye, which is one of the typical characteristics of VHCF fatigue, fracture origin and discussions about the shape of S—N curve, etc The present work also analyzes the fatigue mechanisms and concludes some theoretical models of VHCF fatigue Some possible and prospective aspects of future researches are also proposed