Which property is most important for materials that undergo repeated loading?

The most important property for materials that undergo repeated loading is fatigue strength. Fatigue strength refers to the maximum stress level that a material can withstand for an infinite number of loading cycles without experiencing failure. When materials are subjected to cyclic loading, even if the loads are below the yield strength, they can still develop microscopic cracks that can eventually lead to failure.

Understanding fatigue strength is crucial in applications where components experience varying loads over time, such as in bridges, mechanical parts, and rotating machinery. Ensuring that a material possesses adequate fatigue strength helps in predicting its performance and durability under such conditions, ultimately preventing catastrophic failures.

While other properties, like compressive strength and shear strength, are also important for different loading conditions, they do not specifically address the nuances of repeated loading scenarios. Brittleness, on the other hand, indicates a material's tendency to fracture without significant deformation, which is not desirable in situations involving repeated stress. Thus, fatigue strength stands out as the key property for materials facing repeated loading.