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Numerical and Experimental Study on Vibration Control of Marine Diesel Engin Using MR Dampers

作　者: Muhammad Aslam
导　师: Yao Xiongliang
学　校: 哈尔滨工程大学
专　业: Naval Architecture
关键词: system control vibration Harbin between states model ability force Master design reason isolation foundation Engineers engine general elements machinery range
分类号: U664.121
类　型: 硕士论文
年　份: 2006年
下　载: 15次
引　用: 0次
阅　读: 论文下载

内容摘要

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.

全文目录

ACKNOWLEDGEMENTS  4-5
ABSTRACT  5-7
CHAPTER 1 INTRODUCTION  7-12
CHAPTER 2.0 PROPERTIES OF MAGNETORHEOLOGICAL FLUIDS  12-24
  2.1 Magnetorheological Fluids  12-14
  2.2 Magnetic Materials for MR fluids  14-15
  2.3 Properties of Commercial MR Fluids  15-16
  2.4 Rheology of Magnetorheologieal(MR) Fluids  16-17
  2.5 MR Devices and MR Fluid Dampers  17-18
  2.6 Semi-Active Control Systems  18-21
  2.7 Advantages of MR Fluids as Compared to ER Fluids  21-23
  2.8 Conclusion  23-24
CHAPTER 3.0 VIBRATION CONTROL STRATEGIES  24-35
  3.1 Active Vibration Control  24-25
  3.2 Semi-active Control  25-27
  3.3 Categories of Control  27-33
  3.4 PID Controllers  33
  3.5 Conclusion  33-35
CHAPTER 4.0 NUMERICAL SIMULATIONS OF THE FOUNDATION  35-74
  4.1 Engine Excitations  35-37
  4.2 Theoretical Analysis of the Foundation  37-39
  4.3 Wire Rope Spring  39-45
  4.4 MR Damper Characteristics  45-50
  4.5 Desired Vibration Exciter Characteristics  50-51
  4.6 Modeling of the Foundation  51-54
  4.7 Numerical Simulations of the Foundation  54-63
  4.8 Parametric Study of the Foundation with MR Dampers  63-68
  4.9 Control Simulations  68-73
  4.10 Conclusion  73-74
CHAPTER 5 EXPERIMENTAL SET UP AND RESULTS FOR VIBRATION RESPONSE  74-116
  5.1 Experimental Set Up  74-80
  5.2 Data Acquisition and Processing  80-87
  5.3 Analysis of Dynamic Performance of the Foundation  87-90
  5.4 Transmissibility Analysis  90-95
  5.5 Effect of Mass of the Model  95-97
  5.6 Effect of Excitation Force  97-99
  5.7 Modal Analysis  99-101
  5.8 Shock Testing of the Foundation  101-102
  5.9 Theoretical Modeling  102-104
  5.10 Experimental Set up for Shock Testing  104-106
  5.11 Shock Input  106-108
  5.12 Experimental Results  108-110
  5.13 Vibration Control  110-115
  5.14 Conclusion  115-116
CHAPTER 6.0 COMPARISON OF NUMERICAL AND EXPERIMENTAL RESULTS  116-121
  6.1 Discussion of the Results  118-121
CHAPTER 7.0 CONCLUSION AND RECOMMENDATIONS  121-127
  7.1 Conclusion  121-122
  7.2 Recommendations  122-124
  7.3 PROPOSED MODEL  124-127
References  127-136
Published Papers  136

Numerical and Experimental Study on Vibration Control of Marine Diesel Engin Using MR Dampers

内容摘要

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