This work deals with the analysis in the frequency domain of the temperature signal and mechanical energy rate of C45 steel under two different fatigue stepwise loading series at stress ratios of 0.1 and −1. It was first investigated the energy distribution among the harmonic components of the signals to understand possible variations caused by a different stress ratio. In addition, the second amplitude harmonic (SAH) of heat dissipated and mechanical energy rates have been considered in the analysis, and their relationship was investigated. It has been shown as it depends only on the material, and hence, it is valid whatever the kind of the test is without any assumption on the energy supplied to the material or material hysteresis loop stabilization. The adopted approach allows the analysis of intrinsic dissipations by means of rapid, full-field, and contactless techniques without any specific requirement on loading condition or temperature signal stabilization.

中文翻译：

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C45钢疲劳时机械能率与热耗散率与应力比的关系

这项工作涉及 C45 钢在应力比为 0.1 和 ∼ 1 的两种不同疲劳逐步加载系列下的温度信号和机械能率的频域分析。首先研究了信号谐波分量之间的能量分布，以了解由不同应力比引起的可能变化。此外，分析中还考虑了散热和机械能率的二次振幅谐波（SAH），并研究了它们之间的关系。它已被证明仅取决于材料，因此，无论何种测试，它都是有效的，无需对提供给材料的能量或材料磁滞回线稳定性进行任何假设。所采用的方法允许通过快速、