Fatigue (material)
In materials science, fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. The nominal maximum stress values are less than the ultimate tensile stress limit, and may be below the yield stress limit of the material.
Fatigue occurs when a material is subjected to repeated loading and unloading. If the loads are above a certain threshold, microscopic cracks will begin to form at the surface. Eventually a crack will reach a critical size, and the structure will suddenly fracture. The shape of the structure will significantly affect the fatigue life; square holes or sharp corners will lead to elevated local stresses where fatigue cracks can initiate. Round holes and smooth transitions or fillets are therefore important to increase the fatigue strength of the structure.
Read more about Fatigue (material): Fatigue Life, Characteristics of Fatigue, Timeline of Early Fatigue Research History, High-cycle Fatigue, Low-cycle Fatigue, Fatigue and Fracture Mechanics, Factors That Affect Fatigue-life, Design Against Fatigue
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