Abstract Industrial machinery is often equipped with proximity probes that measure continuously position and vibrations of the shaft, generally relative to the bearings. These measurements are used for surveillance of the machine, and furnish valuable information to be used in a diagnostic process, especially when run-up or run-down transients are recorded and processed. However, a question arises, during normal operating conditions at constant rotating speed can some additional information about the dynamical behavior of the rotating shaft be extracted from these measurements? Considering that in an industrial environment the shaft vibrations are generally affected by some noise transmitted through the supporting structure by other machines operating in the considered industrial plant, where also fluids are moving in pipes and vessels, all generating vibrations, operational modal analysis (OMA) could be used for identifying natural frequencies and modal damping. And which are the conditions of the vibration measurements required to get reliable results from processing the recorded signals? In this context, the present paper aims to analyze, with the aid of a test rig, the conditions in which OMA will result successful. These conditions include both the operating condition of the shaft and the amount and quality of the noise. The test rig, where also noise has been applied to the rotating shaft by means of a magnetic actuator, furnishes some test runs that are analyzed and used for tuning a model that can then be used to explore the different conditions.

中文翻译：

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模拟操作模态分析在试验台上的应用

摘要 工业机械通常配备接近探头，用于连续测量轴的位置和振动，通常相对于轴承。这些测量用于机器的监视，并提供用于诊断过程的有价值的信息，尤其是在记录和处理启动或停止瞬变时。然而，出现了一个问题，在恒定转速的正常运行条件下，是否可以从这些测量中提取有关旋转轴动态行为的一些附加信息？考虑到在工业环境中，轴振动通常受到在所考虑的工业工厂中运行的其他机器通过支撑结构传输的一些噪声的影响，其中流体也在管道和容器中移动，对于所有产生的振动，运行模态分析 (OMA) 可用于识别固有频率和模态阻尼。从处理记录的信号中获得可靠结果所需的振动测量条件是什么？在此背景下，本文旨在借助测试台来分析 OMA 成功的条件。这些条件包括轴的运行条件以及噪音的数量和质量。该测试台还通过磁致动器将噪声施加到旋转轴上，提供一些测试运行，这些运行经过分析并用于调整模型，然后可用于探索不同的条件。从处理记录的信号中获得可靠结果所需的振动测量条件是什么？在此背景下，本文旨在借助测试台来分析 OMA 成功的条件。这些条件包括轴的运行条件以及噪音的数量和质量。该测试台还通过磁致动器将噪声施加到旋转轴上，提供一些测试运行，这些运行经过分析并用于调整模型，然后可用于探索不同的条件。从处理记录的信号中获得可靠结果所需的振动测量条件是什么？在此背景下，本文旨在借助测试台来分析 OMA 成功的条件。这些条件包括轴的运行条件以及噪音的数量和质量。该测试台还通过磁致动器将噪声施加到旋转轴上，提供一些测试运行，这些运行经过分析并用于调整模型，然后可用于探索不同的条件。这些条件包括轴的运行条件以及噪音的数量和质量。该测试台还通过磁致动器将噪声施加到旋转轴上，提供一些测试运行，这些运行经过分析并用于调整模型，然后可用于探索不同的条件。这些条件包括轴的运行条件以及噪音的数量和质量。该测试台还通过磁致动器将噪声施加到旋转轴上，提供一些测试运行，这些运行经过分析并用于调整模型，然后可用于探索不同的条件。