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Mechanical Engineering Commons

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Articles 1 - 5 of 5

Full-Text Articles in Mechanical Engineering

Dynamics Of A Power Line When Supported By A Compliant Energy Absorber , Elias Bitencourt Teodoro Jan 1994

Dynamics Of A Power Line When Supported By A Compliant Energy Absorber , Elias Bitencourt Teodoro

Retrospective Theses and Dissertations

Power lines are subjected to complex aerodynamic forces that may cause galloping. The galloping phenomenon is highly complex because of the nonlinear, geometric-dependent, time-varying aerodynamic loads and the resulting amplitudes of vibration, which may cause interactions between various vibration modes and also between adjacent spans and their support hardware. It is generally agreed that cable galloping is the result of the aerodynamic instability of ice-coated cables. This instability can be defined in terms of measurable aerodynamic properties of the airfoils and the characteristics of the mechanical system. Galloping oscillations can cause interphase clashing, which may lead to flashovers that result ...


Dynamics And Vibrations Of Magnetostrictive Transducers , David L. Hall Jan 1994

Dynamics And Vibrations Of Magnetostrictive Transducers , David L. Hall

Retrospective Theses and Dissertations

An engineering investigation into the dynamics and vibrations of magnetostrictive transducers is conducted. The transducers are examined from a linear systems perspective. The system input is electric current. The system output is displacement. A comparison is made between the classic low-signal linear transduction equations for the material and those for the electromechanical transducer containing the material. A magnetomechanical model is derived assuming the magnetostrictive rod behaves as a linear spring. The model is an expression for the complex valued, frequency, coupling, and load dependant magnetic permeability of the magnetostrictive material within the transducer. One-dimensional analytical constant parameter linear electromagnetic models ...


Efficient Inversion Of Fourier And Laplace Domain Boundary Element Solutions For Elastodynamic Scattering , Joel Kevin Ness Jan 1994

Efficient Inversion Of Fourier And Laplace Domain Boundary Element Solutions For Elastodynamic Scattering , Joel Kevin Ness

Retrospective Theses and Dissertations

In ultrasonic nondestructive testing, the actual time domain signature of a scattered wave due to a pulsed input is the common observable (via oscilloscope) quantity. Numerically simulated solutions are thus desirable in the time domain. These can be obtained by working directly in the time domain or by inversions of integral transform solutions in the frequency (Fourier) or Laplace domains. Direct time solutions are suitable for short times but generally deteriorate for longer times. Alternately, the transform techniques generally require solutions over a wide spectrum in the transform variable to provide accurate inversions back to the time domain. However, without ...


Structural Wave Propagation And Sound Radiation Study Through Time And Spatial Processing , Ruey-Chang Wei Jan 1994

Structural Wave Propagation And Sound Radiation Study Through Time And Spatial Processing , Ruey-Chang Wei

Retrospective Theses and Dissertations

This work explores new usages of experimental and analysis tools to study the relationship between the wave propagation and sound radiation in a structure with inhomogeneities. The focus of the research is to develop and test new and merged techniques. The analysis tools used in the research include: time domain analysis, k-space analysis, and wave speed tracking. With the time domain analysis, one can study the response of any synthetic excitation with only one set of experimental data. The k-space analysis provides insight into locating areas on a vibrating structure that radiate sound to the acoustic farfield. The wave speed ...


Active Noise Control In A Three-Dimensional Space , Jihe Yang Jan 1994

Active Noise Control In A Three-Dimensional Space , Jihe Yang

Retrospective Theses and Dissertations

In this research, a new approach is presented for optimizing the performance of active noise control in three-dimensional space. The work focuses on the critical role of determining the locations for secondary sources in active noise suppression. A systematic technique is proposed for estimating optimal locations of secondary sources on the boundary of a three-dimensional domain for both local and global active control of harmonic sound fields. The theoretical foundation of this work is Huygen's principle. The indirect boundary element method (IBEM) which is a numerical implementation of Huygen's principle is employed as a basis for the numerical ...