Review of Fatigue and Fracture Mechanic in Metals

This chapter briefly introduces the readers to some basic fundamentals of fracture mechanics and fatigue, which are required for the understanding of materials presented in the later chapters. The development of fatigue in metallic structures is a significant concern, and research by Nishida et al . [ 79 ] indicates that it is responsible for 70-80% of all failure cases. Fatigue occurs when localized damage accumulates due to repeated or fluctuating strain or stress levels below the material’s yield strength. This damage can lead to the formation of cracks that grow over time and eventually result in the failure of the component. The damage process requires the combined effect of cyclic stress, tensile stress, and plastic strain. A fatigue crack will not initiate or propagate without one of these three components.