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Articles 1 - 5 of 5
Full-Text Articles in Engineering
Vibration Analysis Of A Fan/Compressor Blade, Daisaku Inoyama
Vibration Analysis Of A Fan/Compressor Blade, Daisaku Inoyama
Master's Theses - Daytona Beach
The vibration of blades in gas turbine engines has become an important issue during the last decade because of its significant impact on high cycle fatigue failure due to resonant vibrations. The main objective of this thesis is the vibration analysis of compressor/fan blade using three-dimensional finite element analysis together with various analytical approaches. First, the analytical solutions were established using various analytical methods, Bernoulli-Euler, Rayleigh, Rayleigh-Ritz, two-dimensional plate, and Timoshenko beam methods. Then, the vibration behaviors of the blade are analyzed in full extent using commercially available finite element solver, MSC.NASTRAN, and correlated with the analytical solutions. The finite …
Time Aliasing Methods Of Spectrum Estimation, Jason F. Dahl
Time Aliasing Methods Of Spectrum Estimation, Jason F. Dahl
Theses and Dissertations
Time aliasing methods of spectrum estimation alter the time representation of a signal for the purpose of improving its frequency domain representation. Time aliasing allows characteristics of longer time window functions to be used with shorter DFT length. Windows designed specifically for use with time aliasing have improved properties compared to conventional windows. Many previous uses of time aliasing, including overlap-and-add methods of digital filtering, have focused on the elimination of time aliasing effects in the frequency domain in order to improve the representation of reconstructed signals in the time domain and have not addressed the issues associated with spectrum …
The Transcendental Eigenvalue Problem And Its Application In System Identification, Kumar Vikram Singh
The Transcendental Eigenvalue Problem And Its Application In System Identification, Kumar Vikram Singh
LSU Doctoral Dissertations
An accurate mathematical model is needed to solve direct and inverse problems related to engineering analysis and design. Inverse problems of identifying the physical parameters of a non-uniform continuous system based on the spectral data are still unsolved. Traditional methods, for the system identification purpose, describe the continuous structure by a certain discrete model. In dynamic analysis, finite element or finite difference approximation methods are frequently used and they lead to an algebraic eigenvalue problem. The characteristic equation associated with the algebraic eigenvalue problem is a polynomial. Whereas, the spectral characteristic of a continuous system is represented by certain transcendental …
Active Vibration Suppression Of Smart Structures Using Piezoelectric Shear Actuators, Brian P. Baillargeon
Active Vibration Suppression Of Smart Structures Using Piezoelectric Shear Actuators, Brian P. Baillargeon
Electronic Theses and Dissertations
Active vibration damping using piezoelectric materials integrated with structural systems has found widespread use in engineering applications. Current vibration suppression systems usually consist of piezoelectric extension actuators bonded to the surface or embedded within the structure. The use of piezoelectric shear actuators/sensors has been proposed as an alternative, where the electric field is applied perpendicular to the direction of polarization to cause shear deformation of the material. We present an exact analysis and active vibration suppression of laminated composite plates and cylindrical shells with embedded piezoelectric shear actuators and sensors. Suitable displacement and electric potential fknctions are utilized to identically …
In-Plane Anisotropy And Temperature Dependence Of Oxygen Phonon Modes In Yba₂Cu₃O₆.₉₅, Jaeho Chung, Takeshi Egami, R. J. Mcqueeney, Mohana Yethiraj, Masatoshi Arai, Tetsuya Yokoo, Yu Nikolaijevitsch Petrov, Herbert A. Mook, Yasuo Endoh, Setsuko Tajima, Christopher D. Frost, Fatih Dogan
In-Plane Anisotropy And Temperature Dependence Of Oxygen Phonon Modes In Yba₂Cu₃O₆.₉₅, Jaeho Chung, Takeshi Egami, R. J. Mcqueeney, Mohana Yethiraj, Masatoshi Arai, Tetsuya Yokoo, Yu Nikolaijevitsch Petrov, Herbert A. Mook, Yasuo Endoh, Setsuko Tajima, Christopher D. Frost, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
Inelastic pulsed neutron scattering measurements on YBa2Cu3O6.95 single crystals indicate that the sample has a distinct a-b plane anisotropy in the oxygen vibrations. The Cu-O bond-stretching-type phonons, which are suspected to interact strongly with charge, are simultaneously observed along the a and b directions due to a 7-meV splitting arising from the orthorhombicity, even though the sample is twinned. The bond-stretching LO branch with the polarization along a (perpendicular to the chain) loses intensity beyond the middle of the zone, indicating branch splitting as seen in doped nickelates, with the second branch being located at …