Fatigue Mechanisms and Design in Conventional and Additive Manufactured Metallic Materials

Fatigue is the predominant lifetime-limiting failure mechanism for engineered components and a fundamental barrier to implementation of lightweight, safety-critical components in the transportation sector. Design for fatigue resistance must incorporate aspects of materials science in the engineering design process to fully utilize the constitutive materials’ latent potential. To this end, the microstructure scale mechanisms of fatigue crack initiation and propagation of conventionally processed and additive manufactured aluminum, steel, and titanium are discussed from both fundamental and heuristic perspectives. Complementary design methods that integrate these phenomena are subsequently discussed, with emphasis on ultrasonic fatigue and fatigue crack growth testing, statistical analysis of fatigue data, and computational modeling techniques. This article collectively assembles a broad and holistic guide to fatigue resistant design methods that provides meaningful guidance to readers with beginner to advanced background knowledge.