Effect of Side Grooves on Fatigue Crack Propagation

抄録

In this report, the authors pointed out the fact that the second stage fatigue crack propagation rate of a side grooved specimen becomes lower than that of a non-side grooved one. And also, they explained above phenomenon using three dimensional finite element method(3D-FEM). Namely, the reduction of the mean stress intensity factor by the addition of the side grooves is the main reason for this phenomenon. Therefore, it is possible to estimate the crack propagation behaviour of the side grooved specimen from that of the non side grooved one using the 3D-FEM without the experimental results of side grooved specimens. Further, the authors propose three simple methods to get the stress intensity factor for the side grooved specimen and show the merit of them. The methods are based on the methods of two dimensional finite element analysis (2D-FEM), the crack opening displacement and the theory of the mechanics of materials.