Definition and Understanding of Material Fatigue

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Definition and Understanding of Material Fatigue is the ability of materials subjected to repeated loads may fracture at stresses considerably lower than the ultimate or maximum strength of the material, and perhaps less than the yield strength. Such failures are referred to as fatigue failures. The failure is gradual or progressive fracture due to the spreading of a small crack formed at a point localized stress. Influencing factors are the range over which the stress extends, the number of cycle of stress, and, to a lesser extent, the speed at which the cycles are applied. The highest stress in a range of stress that can be applied an indefinitely large number of times without danger of fatigue failure is called the endurance limit.