The Study of Fatigue Crack Growth Shape under Mode I Constant Amplitude Loading
An experimental study was performed to study crack shape evolution of 16MnR pressure vessel steel by adopted compact tension (CT) specimens under Mode I constant amplitude loading. A data and numerical analysis of crack shape were conducted and the stress intensity factors (SIF) along crack front were calculated. The results revealed that curve crack shape could be described by elliptic equation properly and was similar in the stable crack growth stage. The initial crack shape was straight at the notch root, so SIF of the center was bigger than that of the surface. When the crack shape was curve, SIF of the center was smaller than that of the surface.
W. F. Tu et al., "The Study of Fatigue Crack Growth Shape under Mode I Constant Amplitude Loading", Applied Mechanics and Materials, Vols. 148-149, pp. 852-855, 2012