Current Search:  Vibration -- Measurement (x)

View All Items

  • CSV Spreadsheet
(1 - 5 of 5)
Mobility power flow analysis of connected thick plates with a step discontinuity
Title
Mobility power flow analysis of connected thick plates with a step discontinuity.
Creator
Faivre d'Arcier, Eric., Florida Atlantic University, Cuschieri, Joseph M.
Abstract/Description
In this thesis the flow of vibration power between two coupled, finite plates of arbitrary thicknesses is considered using a Mobility Power Flow (MPF) approach. The plate structure is divided into substructures and mobility functions are determined for the independent substructures. Power flow expressions are derived based on continuity of forces and displacements. The solution presented here considers the effects of both in-plane waves and out-of-plane waves. The solution is applicable to...
Show moreIn this thesis the flow of vibration power between two coupled, finite plates of arbitrary thicknesses is considered using a Mobility Power Flow (MPF) approach. The plate structure is divided into substructures and mobility functions are determined for the independent substructures. Power flow expressions are derived based on continuity of forces and displacements. The solution presented here considers the effects of both in-plane waves and out-of-plane waves. The solution is applicable to frequencies below the first mode of thickness-shear vibration. The results obtained show that at low frequencies, the out-of-plane waves dominate in the transmission of vibrational power. However, at high frequencies or for thick plates, the in-plane waves play a significant role in the power transmission through the plate.
Show less
Date Issued
1991
PURL
http://purl.flvc.org/fcla/dt/14705
Subject Headings
Vibration--Measurement
Format
Document (PDF)
EXPERIMENTAL MODAL ANALYSIS OF A DISCMILL FIBERIZER DISC (VIBRATION, PLATES, RESONANCES)
Title
EXPERIMENTAL MODAL ANALYSIS OF A DISCMILL FIBERIZER DISC (VIBRATION, PLATES, RESONANCES).
Creator
FREEZE, WILLIAM PRESTON., Florida Atlantic University, Stevens, Karl K.
Abstract/Description
Modal analysis testing techniques were used to determine the modal parameters and mode shapes for flexural vibration of a Fiberizer Discmill disc to help define a safe operating speed range. The modal parameters and mode shapes were determined for the first six diametral modes, the first concentric mode, and the first rigid body shaft mode. The disc consisted of a circular aluminum plate with eight equally and symmetrically spaced radial cutters on one face of the disc and eight equally...
Show moreModal analysis testing techniques were used to determine the modal parameters and mode shapes for flexural vibration of a Fiberizer Discmill disc to help define a safe operating speed range. The modal parameters and mode shapes were determined for the first six diametral modes, the first concentric mode, and the first rigid body shaft mode. The disc consisted of a circular aluminum plate with eight equally and symmetrically spaced radial cutters on one face of the disc and eight equally spaced peripheral cutters located on the rim of the disc midway between the angular locations of the radial cutters. All cutters were of tool steel. The safe area of operation is determined to be between 3000 rpm and 3600 rpm. The experimental setup and procedure Is described in detail with particular emphasis on validation of assumptions required for the analytical approaches used in calculating the modal data.
Show less
Date Issued
1986
PURL
http://purl.flvc.org/fcla/dt/14329
Subject Headings
Milling machinery, Vibration--Measurement
Format
Document (PDF)
INVESTIGATION OF ENERGY FLOW AND ACOUSTIC RADIATION OF FLUID-LOADED PANELS USING THE ENERGY ACCOUNTANCY CONCEPT
Title
AN INVESTIGATION OF ENERGY FLOW AND ACOUSTIC RADIATION OF FLUID-LOADED PANELS USING THE ENERGY ACCOUNTANCY CONCEPT.
Creator
MAILLET, PHILIPPE LOUIS., Florida Atlantic University, Dunn, Stanley E., Cuschieri, Joseph M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The energy flow and the acoustic radiation of fluid-loaded panels are investigated using the Energy Accountancy Concept. The various energy components of the systems are defined and studied. Each component is a function of the excitation, the structure, the medium and their coupling. An energy balance equation is written for the system. This method is applied to study the acoustic radiation from a point-excited clamped plate placed on the free surface of a water tank. The radiation efficiency...
Show moreThe energy flow and the acoustic radiation of fluid-loaded panels are investigated using the Energy Accountancy Concept. The various energy components of the systems are defined and studied. Each component is a function of the excitation, the structure, the medium and their coupling. An energy balance equation is written for the system. This method is applied to study the acoustic radiation from a point-excited clamped plate placed on the free surface of a water tank. The radiation efficiency of the plate is measured and compared to previous works. The energy balance equation gives very good results at frequencies between 50 Hz and 12 kHz. An undefined source of energy dissipation is observed in one experiment. The results of this study have shown that the Energy Accountancy Concept can be used to describe the energy flow in a vibrating structure under water-loading.
Show less
Date Issued
1986
PURL
http://purl.flvc.org/fcla/dt/14289
Subject Headings
Acoustic radiation pressure, Vibration--Measurement
Format
Document (PDF)
Detection, localization, and identification of bearings with raceway defect for a dynamometer using high frequency modal analysis of vibration across an array of accelerometers
Title
Detection, localization, and identification of bearings with raceway defect for a dynamometer using high frequency modal analysis of vibration across an array of accelerometers.
Creator
Waters, Nicholas., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This thesis describes a method to detect, localize and identify a faulty bearing in a rotating machine using narrow band envelope analysis across an array of accelerometers. This technique is developed as part of the machine monitoring system of an ocean turbine. A rudimentary mathematical model is introduced to provide an understanding of the physics governing the vibrations caused by a bearing with a raceway defect. This method is then used to detect a faulty bearing in two setups : on a...
Show moreThis thesis describes a method to detect, localize and identify a faulty bearing in a rotating machine using narrow band envelope analysis across an array of accelerometers. This technique is developed as part of the machine monitoring system of an ocean turbine. A rudimentary mathematical model is introduced to provide an understanding of the physics governing the vibrations caused by a bearing with a raceway defect. This method is then used to detect a faulty bearing in two setups : on a lathe and in a dynamometer.
Show less
Date Issued
2012
PURL
http://purl.flvc.org/FAU/3359156
Subject Headings
Marine turbines, Mathematical models, Vibration, Measurement, Fluid dynamics, Dynamic testing
Format
Document (PDF)
Vibration analysis for ocean turbine reliability models
Title
Vibration analysis for ocean turbine reliability models.
Creator
Wald, Randall David., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
Submerged turbines which harvest energy from ocean currents are an important potential energy resource, but their harsh and remote environment demands an automated system for machine condition monitoring and prognostic health monitoring (MCM/PHM). For building MCM/PHM models, vibration sensor data is among the most useful (because it can show abnormal behavior which has yet to cause damage) and the most challenging (because due to its waveform nature, frequency bands must be extracted from...
Show moreSubmerged turbines which harvest energy from ocean currents are an important potential energy resource, but their harsh and remote environment demands an automated system for machine condition monitoring and prognostic health monitoring (MCM/PHM). For building MCM/PHM models, vibration sensor data is among the most useful (because it can show abnormal behavior which has yet to cause damage) and the most challenging (because due to its waveform nature, frequency bands must be extracted from the signal). To perform the necessary analysis of the vibration signals, which may arrive rapidly in the form of data streams, we develop three new wavelet-based transforms (the Streaming Wavelet Transform, Short-Time Wavelet Packet Decomposition, and Streaming Wavelet Packet Decomposition) and propose modifications to the existing Short-TIme Wavelet Transform. ... The proposed algorithms also create and select frequency-band features which focus on the areas of the signal most important to MCM/PHM, producing only the information necessary for building models (or removing all unnecessary information) so models can run on less powerful hardware. Finally, we demonstrate models which can work in multiple environmental conditions. ... Our results show that many of the transforms give similar results in terms of performance, but their different properties as to time complexity, ability to operate in a fully streaming fashion, and number of generated features may make some more appropriate than others in particular applications, such as when streaming data or hardware limitations are extremely important (e.g., ocean turbine MCM/PHM).
Show less
Date Issued
2012
PURL
http://purl.flvc.org/FAU/3359158
Subject Headings
Marine turbines, Mathematical models, Fluid dynamics, Structural dynamics, Vibration, Measurement, Stochastic processes
Format
Document (PDF)