Development of the identification method of both the depth and position of the breathing crack in the rotating shaft

本研究发展并完善了旋转轴开放性裂纹的简明、精确、通用的有限元模型。建立了两种张开裂纹模型，讨论并提出了这两种裂纹模型参数的确定方法，并通过静态和旋转状态下的固有频率实验进行了验证。并对裂纹引起的双频振动进行了理论分析。将双频振动的理论和实验共振曲线进行了比较，证实了它们的定量一致性。结果表明，所建立的旋转轴裂纹模型的准确性和理论分析的有效性。利用这些分析，可以反求出张开裂纹的深度和位置信息。最后，对呼吸裂纹进行了建模，并开发了简单裂纹转子有限元模型的数值模拟程序。

This study developed and improved the concise, accurate and general purpose oriented finite element model of an open crack in the rotating shaft. Two models of the open crack were developed, and the determining methods of the parameters involved in these crack models are discussed and proposed, and it is verified by investigating the natural frequencies in both static and rotating conditions experimentally. Furthermore, the theoretical analysis of the double-frequency vibration due to crack is performed. Both the theoretical and the experimental resonance curves of the double-frequency vibration are compared, and their quantitative agreement is confirmed. As the result, the accuracy of the developed crack model of the rotating shaft and the validity of the theoretical analysis are clarified. The information of both the depth and position of the open crack can be obtained by using these analyses inversely. Finally, the modeling of the breathing crack was performed, and the numerical simulation code for the simple FEM cracked rotor model was developed.