Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 31 for “"Vibration Reduction"”.
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Residual vibration reduction in computer controlled machines
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1989.
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Analysis of vibration reduction via local structural modification
… problems. This thesis develops methods for vibration reduction via local structural modification. In this thesis, the reduction of unwanted vibration in a structural system is principally analysed in two ways, (i) relocation of resonance, and (ii) relocation of anti-resonance - both of which …
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Application of smart materials for vibration reduction in ships
… industries to measure and control noise and vibration. This study covered ship structure vibration and Smart Materials were employed for the purpose of ship vibration attenuation. One specific Smart Material, piezoelectric material, was the focus of the study. Although previous research has …
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Vibration reduction of marine cable systems using dynamic absorbers
Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1996.
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Integral twist actuation of helicolpter rotor blades for vibration reduction
Active integral twist control for vibration reduction of helicopter rotors during forward flight is investigated. The twist deformation is obtained using embedded anisotropic piezocomposite actuators. An analytical framework is developed to examine integrally-twisted blades and their aeroelastic …
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Higher harmonic blade pitch control : a system for helicopter vibration reduction
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1980.
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Towards A Mobile Damping Robot For Vibration Reduction of Power Lines
… against harsh environments such as wind-induced vibration (WIV). Currently, Inspection robots are used for maintenance efforts while fixed tuned mass dampers (FTMDs) are used to prevent structural damages. However, both solutions are facing many challenges. Inspection robots are limited by their …
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Energy Harvesting toward the Vibration Reduction of Turbomachinery Blades via Resonance Frequency Detuning
… remote devices as ambient mechanical energy from vibrations is converted to electrical energy. These devices have numerous potential applications, including actuation, sensing, structural health monitoring, and vibration control -- the latter of which is of particular interest here. This work …
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Theoretical and experimental study on cable vibration reduction with a TMD-MR damper
… of their low intrinsic damping. Excessive cable vibrations cause frequent maintenance and are detrimental to the safety of the entire bridge. Targeting the severe cable vibration problem, in addition to using the existing Magnetorheological (MR) damper, the current study proposes a new type of …
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Determination of Frequency-Based Switch Triggers for Optimal Vibration Reduction via Resonance Frequency Detuning
… detuning (RFD) is a piezoelectric-based vibration reduction approach that applies to systems experiencing transient excitation through the system*s resonance—for example, turbomachinery experiencing changes in rotation speed, such as on spool-up and spool-down. This technique relies on …
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A feasibility study of helicopter vibration reduction by self-optimizing higher harmonic blade pitch control.
Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. Thesis. 1967. M.S.
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Vibration Reduction of a Semisubmersible Floating Wind Turbine using Optimized Tuned Mass and Tuned Inerter Dampers
… based structural control methods can have on vibration reduction of floating offshore wind turbines. Models are developed adding tuned mass dampers (TMD) and tuned inerter dampers (TID) into the three main columns of a semisubmersible platform. Results showed that for free decay tests, heave …
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Vibration Reduction and Energy Harvesting using Motion-Rectified Tuned Mass-Damper-Inerters in Semi-Submersible Offshore Wind Platforms
… floating structures such as semi-submersibles. Vibrations in the pitch and heave directions associated with greater yaw-bearing and tower-base bending moments, respectively, reduce the lifespan of these structures. This paper compares traditional tuned-mass dampers (TMDs) and tuned-mass damper …
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Numerical and field data analysis of drill stem vibration
<p>"Drill stem vibration is a major cause of premature failure of drill stem components and drilling inefficiency. In severe cases, drill stem vibration may lead to wellbore instability that could lead to increased operational cost. Drill stem vibrations are affected by design decisions and the …
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Novel Lightweight Noise and Vibration Control Treatments for Marine Structures
… the development and testing of distributed vibration absorber designs with specific application to heavy plates for the reduction of vibration and sound radiation. Two particular designs, already under investigation for use on thin panels or composite materials, were adapted to passively …
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A linear parameter varying control methodology for reduction of helicopter higher harmonic vibration
Vibration in helicopters can have a significant impact on their utility, maintenance, weight, performance, and cost of operation. This thesis focuses on the design of a vibration reduction controller that is effective throughout the flight envelope of the helicopter, in spite of variations in …
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Vibration isolation systems using hysteretic multiple tuned mass damper oscillators
The subject of this study is the vibration isolation effect of linear and nonlinear hysteretic single degree of freedom oscillators attached to a structure. The system of oscillators, attached to the main structure, reduce the amplitude of its structural response, over a wide frequency band …
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Characterisation and Modelling for Elastomeric and Gel-Like Magnetorheological Materials
… especially in civil engineering, involving vibration reduction and isolation for infrastructures. However, some MR materials have inherent limitations: sedimentation and instability of MR fluid, and low MR effect and large energy consumption of MR elastomer. MR gels were fabricated to gain …
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Design and implementation of a piezoelectric servo-flap actuation system for helicopter rotor individual blade control
… 1/rev, 3/rev, 4/rev, 5/rev, and 6/rev harmonic vibration has been successfully demonstrated. The peak vibrations were eliminated at each frequency, as well as the vibrations over a small bandwidth surrounding each peak. Experimental comparison of continuous time versus discrete time control has …
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