This paper presents an approach to simplify the design process for fatigue life requirement, when dealing with variable amplitude load history. The basic concept is to use the load history data and the material fatigue properties to calculate the fatigue life for different stress levels, using the contemporary fatigue life approach. The stress level and fatigue life data are then related by a simple power function and the constants of this function are calculated. The stress level for a required life, or the fatigue life at certain stress level, can be obtained using the power function in a way similar to the S-N curve. To demonstrate the approach some test cases using the SAE keyhole specimen fatigue data, for different load histories, are presented.

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