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原文传递 Numerical and Experimental Study on Vibration Control of Marine Diesel Engin Using Mr Dampers

论文题名：	Numerical and Experimental Study on Vibration Control of Marine Diesel Engin Using Mr Dampers
关键词：	船用柴油机;振动控制;MR阻尼器;数值模拟
摘要：	Ship manufacturers invest considerable effort and money in improving the attenuation of noise radiated by ship into the water. A number of different noise sources contribute to the total acoustic signature on a ship. This dissertation focuses on the problem associated with low order harmonics generated by the diesel engines, transmitted through the engine mounts into the hull, and subsequently radiating into the water. The main intention of the work described here is to experimentally and numerically investigate the use of MR dampers to minimize the vibratory energy of the low speed diesel engine transmitted to the hull. Moreover, properties and control strategies are also investigated to develop a fundamental understanding of MR dampers for the purpose of designing and implementing these "smart" damping devices in vibration control. This dissertation shows the feasibility of using semi-active vibration control to attenuate the vibrations of the diesel engine used onboard ships. It is expected that if the vibrations of the engine to the base are reduced, the vibratory energy transmitted from the engines to the hull and then radiated into the water, would also decrease. To evaluate the feasibility of using a semi-active system, a complete engine foundation was built with the same physical properties and dimensions as a foundation on a real ship. The foundation was equipped with four MR dampers two on each side and six passive wire rope spring isolaters. A test rig,to simulate the excitation force of the diesel engine is arranged in the laboratory at Harbin Engineering University and used for the real-time semi-active control experiments described here. On/Off control strategy is used to control the vibration. Use of MR dampers to control shock is also investigated. MR dampers were used to generate the control forces and accelerometers and force sensors were used to provide controller vibration and error signals respectively and a measure of the control system performance. A reduction in the vibratory force of the engine harmonics transmitted through the MR dampers and wire rope springs will result in a similar reduction in the portion of the acoustic signature attributable to this path. Two different experimental set-ups of the complete engine foundation were evaluated. The first set-up was to evaluate the response of the structure for harmonic force and the second set-up was to evaluate the response of the foundation for transient excitations caused by underwater explosion docking or weapon firing. Simulation results demonstrate that MR dampers used in conjunction with appropriate control strategies are effective and practically implement able in the vibration control applications.
作者：	MUHAMMAD ASLAM
专业：	Naval Architecture
导师：	YAO XIONGLIANG
授予学位：	硕士
授予学位单位：	哈尔滨工程大学
学位年度：	2006
正文语种：	中文