• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.279-285
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• 2019

Transverse vibrations of a ship's aft end and deckhouse are mainly induced by transverse exciting forces from the main engine. Resonance should be avoided in the initial design stages when there is a prediction of resonance between the main engine and transverse modes of the deckhouse. Estimates of frequencies for resonance avoidance are possible from the specifications of the main engine and propeller, but the inherent vibration frequency of the structure around the engine room is not easy to estimate due to the variation in the shape. Experience-oriented vibration design is also carried out, which results in many problems, such as process delay, over-injection of on-site personnel, and iterative performance of the design. For the flexible design of 8,600 TEU container vessels, this study addressed the resonance problem caused by the transverse vibration of the main engine when only the main engine was changed from 12 cylinders to 10 cylinders without modification of the hull structure layout. Efficient structural reinforcement design guidelines are presented for avoiding resonances with the main engine lateral vibration and the structure around the engine room. The guidelines are expected to be used as practical design guidelines at design sites.

• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.55-59
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• 2013

Transverse vibrations of ship's aft end and deckhouse among the various modes of hull structures are induced mainly by transverse exciting forces and moments of main engine such as ${\times}$ and h-moment. Avoidance of resonance should be made in a intial design stage in case there is a prediction for resonance between main engine and transverse modes of deckhouse. This study shows a case of change in type of main engine from 12 cylinders to 10 without modification of hull structures in engine room requested by a shipowner of 8,600 TEU class container carrier and proposes a guide to the effective ways of structural arrangement for avoiding resonance between transverse exciting force and surrounding structures of main engine in engine room through case studies.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.251-255
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• 2012

Structural intensity has been mainly utilized to identify vibration energy flow in a vessel. In this paper, the structural intensity of a shuttle tanker subjected to H-moment of the main engine was calculated using a finite element model. From the analysis, it was found that the top-bracing elements, which support the main engine onto the hull structure to prevent the excessive transverse vibration of the main engine, play the role of the dominant path and sink for vibration energy flow from the main engine. Therefore, the structural intensity was controlled by the modification of stiffness and damping characteristics of the top-bracing elements. As a result, it is observed that the transverse vibration level at the center of navigation bridge deck decreased after the control of structural intensity.