Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Matthew Valentine Thompson. / B.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 117-118. / by David Edward Dunfee. / M.S.

Lau Yiu Kee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 142-146). / Abstracts in English and Chinese. / LIST OF TABLES --- p.viii / LIST OF FIGURES --- p.x / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Railway Vehicle Suspension --- p.2 / Chapter 1.3 --- Semi-Active Magnetorheological Fluid Damper --- p.3 / Chapter 1.4 --- Research Objectives --- p.4 / Chapter 1.5 --- Thesis Outline --- p.5 / Chapter 2. --- BACKGROUND --- p.7 / Chapter 2.1 --- MR Fluids --- p.7 / Chapter 2.1.1 --- Composition of MR fluids --- p.7 / Chapter 2.1.2 --- Properties and characteristics of MR fluids --- p.8 / Chapter 2.1.3 --- Literature review --- p.13 / Chapter 2.2 --- MR Devices --- p.13 / Chapter 2.2.1 --- Advantages of MR devices --- p.13 / Chapter 2.2.2 --- Common device geometries --- p.14 / Chapter 2.2.3 --- MR fluid based applications --- p.15 / Chapter 2.2.4 --- Literature review --- p.19 / Chapter 2.3 --- Overview of Railway Vehicles --- p.21 / Chapter 2.3.1 --- "Passive, active and semi-active suspensions" --- p.21 / Chapter 2.3.2 --- Basic railway vehicle structure --- p.23 / Chapter 2.3.3 --- Literature review --- p.25 / Chapter 2.4 --- Railway Vehicle Suspension Systems --- p.25 / Chapter 2.4.1 --- Primary vertical suspension --- p.25 / Chapter 2.4.2 --- Secondary vertical suspension --- p.27 / Chapter 2.4.3 --- Secondary lateral suspension --- p.27 / Chapter 2.4.4 --- Yaw suspension --- p.28 / Chapter 3. --- DESIGN CONSIDERATIONS FOR MR DAMPERS --- p.29 / Chapter 3.1 --- Overview of Existing MR Dampers --- p.29 / Chapter 3.1.1 --- Monotube MR fluid damper --- p.29 / Chapter 3.1.2 --- Double-ended MR damper --- p.31 / Chapter 3.1.3 --- Bellow type MR damper --- p.35 / Chapter 3.2 --- Optimal Design and Configuration of Magnetic Circuit --- p.35 / Chapter 3.2.1 --- Magnetic circuit and magnetic field orientation --- p.35 / Chapter 3.2.2 --- Physical dimension of MR damper --- p.38 / Chapter 3.2.3 --- Connection polarity of electromagnetic circuit --- p.40 / Chapter 3.3 --- Basic Geometry Design Considerations --- p.43 / Chapter 3.3.1 --- Controllable force and dynamic range --- p.43 / Chapter 3.3.2 --- Geometry constraints --- p.45 / Chapter 3.3.3 --- Magnetic circuit design --- p.47 / Chapter 4. --- DEVELOPMENT AND FABRICATION OF MR DAMPERS --- p.51 / Chapter 4.1 --- Pneumatic Air Cylinder --- p.51 / Chapter 4.2 --- Fabrication Process of Double-Ended MR Dampers --- p.55 / Chapter 4.2.1 --- Modifications on the pneumatic air cylinder --- p.55 / Chapter 4.2.2 --- Manufacturing processes of the piston sleeve --- p.56 / Chapter 4.2.3 --- Modification processes of the original piston rod --- p.59 / Chapter 4.2.4 --- Modification of the piston staging area --- p.60 / Chapter 4.2.5 --- Copper wire wrapping and damper assembling --- p.63 / Chapter 5. --- EXPERIMENTAL SETUP AND RESULTS --- p.66 / Chapter 5.1 --- Experimental Setup for the Double-Ended MR Damper --- p.66 / Chapter 5.1.1 --- Instron 8801 loading machine --- p.66 / Chapter 5.1.2 --- Experimental setup for testing the MR damper --- p.67 / Chapter 5.2 --- Force-Lag Phenomenon of MR Damper --- p.70 / Chapter 5.2.1 --- Force-lag phenomenon --- p.70 / Chapter 5.2.2 --- Reasons of the force-lag phenomenon --- p.73 / Chapter 5.2.3 --- Methods to eliminate the force-lag phenomenon --- p.76 / Chapter 5.2.4 --- Setup for hydraulic pump system --- p.77 / Chapter 5.2.5 --- Results and effects of the pressurized MR damper --- p.79 / Chapter 5.3 --- Experimental Results for Testing the MR Damper --- p.83 / Chapter 6. --- SIMULATION RESULTS OF SEMI-ACTIVE TRAIN SUSPENSION --- p.87 / Chapter 6.1 --- MR Damper Model --- p.87 / Chapter 6.2 --- Rail Vehicle Model --- p.92 / Chapter 6.3 --- Semi-Active Railway Suspension --- p.94 / Chapter 6.3.1 --- Lateral vibration on the train --- p.94 / Chapter 6.3.2 --- Semi-active control strategy --- p.95 / Chapter 6.4 --- Simulation Results --- p.98 / Chapter 6.4.1 --- Lower sway mode excitation --- p.99 / Chapter 6.4.2 --- Upper sway mode excitation --- p.105 / Chapter 6.4.3 --- Mixed sway mode excitation --- p.110 / Chapter 6.4.4 --- BR high speed assault course --- p.116 / Chapter 6.4.5 --- Discussions --- p.124 / Chapter 6.5 --- Effects of Vibration on Ride Comfort --- p.128 / Chapter 7. --- CONCLUSIONS --- p.134 / APPENDIX --- p.136 / BIBLIOGRAPHY --- p.142

It has been found that the composites of carbon nanotubes (CNTs) and epoxy resin could greatly enhance damping ability while the stiffness is kept at a very high level. In this research, carbon nanotube enhanced epoxy resin is fabricated. The dynamic properties of the nanotube composites are evaluated. A testing apparatus for obtaining composite dynamic properties is set up and measurement procedures are given. Multiple groups of specimens are made for investigations. In particular, the loss factors together with dynamic stiffness are measured for the specimens with different CNT weight ratio. Experimental results show that CNT additive can provide the composite with several times higher damping as compared with pure epoxy. The composite is much stiffer than viscoelastic material (VEM) while the damping is comparable when strain is above certain level. In order to further study the damping mechanism of the CNT composite, models are developed. Composite unit cell models containing single CNT segments are built by using finite element method (FEM). Models with varying CNT orientations are considered in order to describe the behaviors of the randomly oriented CNTs inside the epoxy matrix. Composite loss factors are calculated based on the average ratio of the unit cell energy loss to the unit cell energy input. Calculated loss factors under different strain levels are compared to experimental results. With the validated model, parametric study is thereafter performed. Parameters such as CNT dimensions and CNT alignment orientation are studied. Those factors lead to higher composite damping capacity are identified. / by Dai, Ruoli. / "September 2007." / Adviser: Wei-Hsin Liao. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4978. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 93-97). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Hard disk drives (HDDs) are the most important information storage devices for computers. Positioning precision is crucial to today's increasingly high-speed, high-capacity, high data density, and miniaturized HDDs. Therefore, the demand for higher bandwidth servo systems that can quickly and precisely position the read/write head on a high track density becomes more pressing. Recently, the idea of applying dual-stage actuators to track servo systems has been studied. The push-pull piezoelectrically actuated devices have been developed as micro actuators for fine and fast positioning, while the voice coil motor functions as a large but coarse seeking. However, the current dual-stage actuator design uses piezoelectric patches only without passive damping. In this thesis, a dual-stage servo system using enhanced active-passive hybrid piezoelectric actuators is proposed. The actuators improve the existing dual-stage actuators for higher positioning precision and better shock resistance, due to the incorporation of passive damping in the design. The main aim is to develop this hybrid servo system not only to increase the speed of track seeking but also to improve precision of track following servos in HDDs. A new piezoelectrically actuated suspension with passive damping is designed and fabricated for precision positioning of the head while reducing undesirable vibrations. In order to evaluate positioning and track following performances for the dual-stage track servo systems, tasks carried out in the thesis are: (1) to investigate the damping abilities and transmissibilities of the active-passive hybrid micro actuators; (2) to investigate the shock resistance of the dual-stage piezoelectric actuators with passive damping; (3) to implement the synthesized active-passive suspension with enhanced piezoelectric actuators using a composite nonlinear feedback controller. / Chan, Kwong Wah. / "December 2006." / Source: Dissertation Abstracts International, Volume: 68-08, Section: B, page: 5512. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 84-90). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Lam Hiu Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 106-111). / Abstracts in English and Chinese. / abstract --- p.i / 摘要 --- p.iii / acknowledgements --- p.v / table of contents --- p.vi / list of figures --- p.viii / list of tables --- p.xi / Chapter 1 --- introduction --- p.1 / Chapter 1.1 --- Controllable Suspension System --- p.1 / Chapter 1.1.1 --- Automotive Suspension System --- p.2 / Chapter 1.1.2 --- Controllable Devices --- p.4 / Chapter 1.1.3 --- MR Fluid and Damper --- p.5 / Chapter 1.2 --- Vibration Control --- p.5 / Chapter 1.2.1 --- Active Control --- p.5 / Chapter 1.2.2 --- Semi-active Control --- p.6 / Chapter 1.2.3 --- Robust Control --- p.7 / Chapter 1.3 --- Research Objective --- p.7 / Chapter 1.4 --- Thesis Outline --- p.8 / Chapter 2 --- PARAMETRIC STUDY OF SUSPENSION SYSTEMS --- p.9 / Chapter 2.1 --- System Models and Transmissibility --- p.9 / Chapter 2.1.1 --- Passive Suspension System --- p.10 / Chapter 2.1.2 --- Skyhook Suspension System --- p.15 / Chapter 2.1.3 --- Groundhook Suspension System --- p.24 / Chapter 2.1.4 --- Hybrid Suspension System --- p.32 / Chapter 2.1.5 --- Comparison among four suspension systems --- p.41 / Chapter 2.2 --- Characteristics analysis --- p.45 / Chapter 2.2.1 --- Passive Suspension System --- p.45 / Chapter 2.2.2 --- Skyhook Suspension System --- p.47 / Chapter 2.2.3 --- Groundhook Suspension System --- p.50 / Chapter 2.2.4 --- Hybrid Suspension System --- p.52 / Chapter 2.3 --- Stability --- p.54 / Chapter 2.3.1 --- Stability in the Sense of Lyapunov for Suspension Systems --- p.54 / Chapter 2.3.2 --- Stability for four Suspension Systems --- p.57 / Chapter 2.4 --- Optimization --- p.63 / Chapter 2.4.1 --- Single-Degree-of-Freedom Passive System --- p.63 / Chapter 2.4.2 --- Two-Degree-of-Freedom Passive System --- p.65 / Chapter 2.4.3 --- Hybrid Suspension System --- p.67 / Chapter 3 --- SUSPENSION SYSTEM WITH VIBRATION CONTROLLER --- p.71 / Chapter 3.1 --- Two-Degree-of-Freedom Quarter Car Model --- p.71 / Chapter 3.2 --- MR Damper --- p.73 / Chapter 3.3 --- Vibration Controller --- p.75 / Chapter 3.3.1 --- System Controller: Sliding Mode Control --- p.76 / Chapter 3.3.2 --- Damper Controller: Continuous-state Control --- p.83 / Chapter 4 --- SIMULATION RESULTS --- p.85 / Chapter 4.1 --- Transmissibility analysis --- p.86 / Chapter 4.2 --- Simulation --- p.89 / Chapter 4.2.1 --- Test by Bump Excitation --- p.89 / Chapter 4.2.2 --- Test by Random Excitation (White noise) --- p.91 / Chapter 4.2.3 --- Test by Road Elevation Profile --- p.95 / Chapter 5 --- CONCLUSIONS AND FUTURE WORK --- p.99 / Chapter 5.1 --- Summary --- p.99 / Chapter 5.2 --- Future Work and Further Development --- p.100 / Chapter 5.2.1 --- Parametric study of the MR suspension system --- p.100 / Chapter 5.2.2 --- Systematic method for selecting control gains --- p.101 / Chapter 5.2.3 --- New control algorithm --- p.101 / Chapter 5.2.4 --- Extension to half and full car models --- p.102 / Chapter 5.2.5 --- System implementation --- p.102 / appendix / Chapter A.1 --- Additional information of the transmissibility of unsprung mass.… --- p.103 / Chapter A.2 --- Additional figures of the random excitation test: --- p.104 / BIBLIOGRAPHY --- p.106

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 66-67. / by Mark L. Tanquary. / M.S.

This thesis represents the work that has been done by the author during his Master of Engineering Science candidature in the area of vibration control of flexible structures at the School of Mechanical Engineering, The University of Adelaide, between March 2003 and June 2004. The aim of this research is to further extend the application of the Spatial Control Approach for two-dimensional flexible structures for attenuating global structural vibration with the possible implication of reduction in noise radiation. The research was concentrated on a simply supported thin flexible plate, using piezoelectric ceramic materials as actuators and sensors. In this work, active controllers were designed for the purpose of controlling only the first five vibration modes (0-500Hz) of the plate. A spatial controller was designed to minimize the total energy of the spatially distributed signal, which is reflected by the spatial H2 norm of the transfer function from the disturbance signal to the vibration output at every point over the plate. This approach ensures the vibration contributed by all the in bandwidth (0-500 Hz) vibration modes is minimized, and hence is capable of minimizing vibration throughout the entire plate. Within the control framework, two cases were considered here; the case when the prior knowledge of the incoming disturbance in terms of reference signal is vailable and the case when it is not available. For the case when the reference signal is available, spatial feedforward controller was designed; whereas for the case when the reference signal is not available, spatial feedback controller was designed to attenuate the global disturbance. The effectiveness of spatial controllers was then compared with that of the standard point-wise controllers numerically and experimentally. The experimental results were found to reflect the numerical results, and the results demonstrated that spatial controllers are able to reduce the energy transfer from the disturbance to the structural output across the plate in a more uniform way than the point-wise controllers. The research work has demonstrated that spatial controller managed to minimize the global plate vibrations and noise radiation that were due to the first five modes. / Thesis (M.Eng.Sc.)--School of Mechanical Engineering, 2005.

Thesis (Ocean E)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1982. / Supervised by J. Kim Vandiver and Henri O. Berteaux. Includes bibliographical references (leaves 151-153).

University of Macau / Faculty of Science and Technology / Department of Electromechanical Engineering