Damage detection in marine propeller in service R. Azzi, F. Asma∗ Department of Mechanical Engineering, Mouloud MAMMERI University of Tizi-Ouzou, BP 17 RP 15000, Algeria ∗ asma-farid@ummto.dz Keywords: Marine Propeller, Impact Fault, Finite Element Medialization, Damage detection. The damage of marine propellers blades is usually caused by an impact with a foreign object, erosion from cavitation or impurity of the material. The impact of the marine propeller with foreign objects in the water causes small chips on the edge of the blade that are often unnoticed by the user of the boat. This leading edge damage, if not detected and treated, can lead to fatigue cracks. This paper focuses on the detection of this structural defect by vibration analysis of a healthy propeller and a propeller whose leading edge is damaged. A 3D model of marine propeller was developed on a mechanical design software. Damage to the leading edge of the blade was modelled by extrusion material removal in two geometric shapes "V" and "I" of welldefined sizes. A modal analysis was performed on Ansys Workbench for a propeller modelled by a single blade for healthy and damaged configurations. In the first part of the study, the effect of the size, position, and geometric shape of the defects on the modal parameters of the helix was analyzed and discussed. In addition, the influence of this lack of impact on the dynamic response of the blade was analyzed by comparing the dynamic response of a healthy blade with that of a damaged blade. This can be used as a defect detection procedure in marine propellers in service indicating the position and the severity of the defect. References [1] Ino, Y., Tatara, Y., 1984. Failure analysis of propeller blade, NK Tech Bulletin, 58-65. [2] Pantazopoulos, G. A., Toulfatzis, A. I., Tzompanakis, K. A., 2011. Failure Analysis of a Cast Mn-Bronze Propeller. Journal of Failure Analysis and Prevention, 11(3), 186-192. [3] Chang-Sup L., 2002. Analysis of the structural failure of marine propeller blades, Journal of Ship & ocean technology, Sotech 6(3), 37-45. [4] Carlton, J., 2018. Marine Propellers and Propulsion, Fourth Edition, Butterworth-Heinemann, Elsevier. [5] Saito, A., 2009. Nonlinear vibration analysis of cracked structures- application to turbomachinery rotors with cracked blades. PhD thesis, the University of Michigan. [6] Epps, B.P., Kimball, R.W., 2013. OpenProp v3: Open-source software for the design and analysis of marine propellers and horizontal-axis turbines. [7] Huang, Z., Xiong, Y., Yong, G., 2016. Composite propeller’s strain modal and structural vibration performance. Chinese Journal of Ship Research, 11(2). 106
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