Inclined Fatigue Crack Growth Mechanism from Notch
Chiaki IHARA and Takeyuki TANAKA
Abstract:Recently the relation between the fatigue crack propagation and slip behavior around the crack tip has been researched by means of an Atomic Force Microscope (AFM). In the previous paper, we explained Mode Ⅰ fatigue crack propagation using a stochastic damage accumulation model for crack propagation based the observation results by AFM. In this paper, the inclined fatigue crack growth process from the notch is analyzed by the use of the method introduced in above model. As the result, the following were found. (1) The inclined crack grows in mixed mode of Mode Ⅰ and Ⅱ by continued destruction owing to the equal release rate g. (2) When the crack changes its direction, it continues to propagate in mode Ⅰ, because ΔKeff in mode Ⅰ obtained from above g is beyond ΔKeff th. Key Words: Inclined fatigue crack, Mixed mode of Mode Ⅰ and Ⅱ crack growth, Mode Ⅰ fatigue crack propagation, AFM image