Fatigue Life Prediction Under Constant Amplitude and Interspersed Mode-I and Mixed-Mode (I and II) Overload using An Exponential Model

Fatigue performance of structures is greatly affected by the presence of stress raisers such as fastener holes, manufacturing errors, corrosion pits, and maintenance damage which serve as nucleation sites for fatigue cracking. During service, sub-critical cracks nucleate from these sites and grow till catastrophic failure takes place when the crack length reaches a critical dimension. A structure can not be retired from service simply on detecting a fatigue crack. Hence, proper evaluation of fatigue crack propagation and residual life prediction of structures (aircraft, ship, railways, bridges, gas and oil transmission pipelines, etc.) are important to ensure the public safety, environmental protection, and economical consideration.