Effect of Drilling Process on Fatigue Life of Open Holes

In this paper,a series of fatigue tests were performed to study the effect of drilling process on fatigue behavior of open holes in dog-bone specimens drilled by the traditional drilling process and advanced Winslow drilling process.The evaluations of initial fatigue qualities of the two types of holes were carried out based on the equivalent initial flaw size method and coincidence criterion.Fatigue fracture surfaces were observed by stereomicroscope.The results show that the location where the fatigue crack initiates is unchanged when these two different drilling processes are used.A longer fatigue life shows a more severe dispersibility.When the Winslow drilling process is adopted,the equivalent initial flaw size is smaller than 0.125 mm.The Winslow drilling process meets the requirement of coincidence criterion.