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Full-Text Articles in Engineering
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 …