혼합모드에서 응력비 변화에 따른 피로균열 진전거동

The complicated stress modes which are common in most machine structures and parts make the analysis of fracture mechanism The fracture mechanism which are common in most machine structures and parts shows mixed-mode stress. It is very difficult to analyze its behavior using numerical method. In this study, the experiment of fatigue crack growth as varying of stress ratio was carried out and its effects was analyzed. And existence of fatigue fracture closure was observed through fractured surface.