Abstract The present work aims at finding an approach to calculate fatigue damage from three-dimensional vibration measurements, with a key objective to define a reliable measurement quantity to predict local stresses. Existing theoretical concepts highlight an exploitable relation to modal velocity. A hysteresis counting based on velocity measurements as well as damage accumulation using S–N curves is proposed. While existing methods consider only uniaxial shaker test setups, there is also a need for fatigue calculation under a three-dimensional shaker setup. This paper also derives a method for fatigue calculation for structures under three-dimensional excitation using the equivalent stress concept. The proposals are also validated using a real mechanical structure and the results indicate better applicability than existing methods.

中文翻译：

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多轴疲劳损伤评估：一种基于模态速度的新方法

摘要 目前的工作旨在寻找一种从三维振动测量中计算疲劳损伤的方法，其关键目标是定义一个可靠的测量量来预测局部应力。现有的理论概念强调了与模态速度的可利用关系。提出了基于速度测量以及使用 S-N 曲线的损伤累积的滞后计数。虽然现有方法仅考虑单轴振动台测试设置，但也需要在三维振动台设置下进行疲劳计算。本文还推导出了一种利用等效应力概念进行三维激励下结构疲劳计算的方法。这些建议还使用真实的机械结构进行了验证，结果表明比现有方法具有更好的适用性。