In the last four decades, the vibrational behaviour of cracked shafts has been investigated to avoid significant rotor faults that may lead to catastrophic shaft failures, if undetected. The diagnosis of these cracked shafts remains problematic. In general, the behaviour of the shaft is insensitive to the presence of cracks. Sometimes, it is difficult to find differences in states of vibration, even if the crack is large. Thus, it is of the utmost importance to discover the effect of the presence of a crack on the characteristics of a shaft. In this study, experimental and numerical investigations are carried out to identify the existence of cracks in shafts. The shaft used in this study is continuous over two spans (with a cantilever span carrying a propeller) with ball-bearing supports; it is driven by an electric-motor having a rated speed of 4000 rpm. This setup is made to monitor the presence of a crack in a rotating shaft. During modal tests the shaft is fixed to one of the supports. The effects of the presence of a crack on three types of vibration, viz., longitudinal, lateral, and torsional are investigated. Shaft response parameters are obtained by using modal analysis software, LMS Test Lab™. Effects of different crack depths are investigated experimentally and numerically.
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机译：在过去的四十年中，已经对裂纹轴的振动行为进行了研究，以避免重大的转子故障（如果未发现），可能导致灾难性的轴故障。这些开裂的轴的诊断仍然存在问题。通常，轴的行为对裂纹的存在不敏感。有时，即使裂纹很大，也很难找到振动状态的差异。因此，最重要的是发现裂纹的存在对轴的特性的影响。在这项研究中，进行了实验和数值研究，以确定竖井中是否存在裂纹。本研究中使用的轴在两个跨度（带有螺旋桨的悬臂跨度）上是连续的，并带有滚珠轴承支撑。它由额定转速为4000 rpm的电动机驱动。进行此设置是为了监视旋转轴中是否存在裂纹。在模态测试期间，将轴固定到其中一个支架上。研究了裂纹的存在对三种振动的影响，即纵向，横向和扭转。轴响应参数是通过使用模态分析软件LMS Test Lab™获得的。实验和数值研究了不同裂纹深度的影响。
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