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Title: ACOUSTIC EMISSIONS TESTING OF PRESTRESSED CONCRETE IN AN ACCELERATED STATE OF CORROSION.
Creator: BABAKANIAN, RUBIK., Florida Atlantic University, Dunn, Stanley E.
Abstract/Description: The acoustic emission (AE) testing reported herein was conducted on a large size prestressed concrete slab placed in contact with sea water in a state of electrically induced accelerated corrosion. AE signals were monitored and successfully analyzed in an attempt to evaluate the severity of the deformation process in the concrete as a result of the corrosion induced cracking. Several features of the AE data which were sensitive to the process were plotted to show the different levels of the...
Show moreThe acoustic emission (AE) testing reported herein was conducted on a large size prestressed concrete slab placed in contact with sea water in a state of electrically induced accelerated corrosion. AE signals were monitored and successfully analyzed in an attempt to evaluate the severity of the deformation process in the concrete as a result of the corrosion induced cracking. Several features of the AE data which were sensitive to the process were plotted to show the different levels of the cracking due to the corrosion. These were amplitude, counts and energy distributions, and event distribution with time. A location test was employed to find the source of the activities. The results of the amplitude distributions were found to have similar characteristics to those obtained from the reinforced concrete AE experiments performed at Florida Atlantic University (1,2). These tests can be easily applied to a field location for an early detection of the deformation process in the concrete structures.
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Date Issued: 1984
PURL: http://purl.flvc.org/fcla/dt/14230
Subject Headings: Prestressed concrete, Acoustic emission testing
Format: Document (PDF)

Title: AN INVESTIGATION OF THE EFFECT OF SOURCE MEASUREMENT TECHNIQUES ON THE COHERENCE FUNCTION.
Creator: BULLWINKEL, PAUL EDWARD., Florida Atlantic University, Dunn, Stanley E.
Abstract/Description: This report presents the results of an experimental investigation of the effects of using different source measurement techniques in implementing the coherence function for source identification purposes. Frequency domain measurements leading to the coherence function are developed with regard to providing a causal relation for a single input, single output, linear system. The use of a near microphone or accelerometer for source measurements is presented with particular interest paid to the...
Show moreThis report presents the results of an experimental investigation of the effects of using different source measurement techniques in implementing the coherence function for source identification purposes. Frequency domain measurements leading to the coherence function are developed with regard to providing a causal relation for a single input, single output, linear system. The use of a near microphone or accelerometer for source measurements is presented with particular interest paid to the effect of introducing noise into the input measurement. Experimental results show that while a near microphone provides a more accurate coherence statement than an accelerometer, the input of correlated noise may be a problem. The possibility of an empirical criteria for the source to noise signal difference at the near microphone is raised as a means to help avoid this problem.
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Date Issued: 1978
PURL: http://purl.flvc.org/fcla/dt/13930
Subject Headings: Spectrum analysis--Research, Sound analyzers--Research
Format: Document (PDF)

Title: A METHOD FOR ACOUSTICALLY MODELING THE REACTION OF A DIVING MASK ON THE HUMAN VOCAL TRACT.
Creator: CZARNECKI, MICHAEL., Florida Atlantic University, Dunn, Stanley E.
Abstract/Description: This investigation presents the development of an acoustical model for the study of the reaction of a diving mask on the human vocal tract. The vocal tract and mask cavity are approximated by simplified acoustic elements of uniform geometry within which undamped plane wave motion is assumed. Equations for the impedance at the mouth opening both with and without a theoretical mask cavity are developed from the one-dimensional wave equation. The results are compared with an analysis of the same...
Show moreThis investigation presents the development of an acoustical model for the study of the reaction of a diving mask on the human vocal tract. The vocal tract and mask cavity are approximated by simplified acoustic elements of uniform geometry within which undamped plane wave motion is assumed. Equations for the impedance at the mouth opening both with and without a theoretical mask cavity are developed from the one-dimensional wave equation. The results are compared with an analysis of the same system using the lumped parameter technique. The impulse response of the mouth opening is found by numerical methods and the extension of the technique to the study of theoretical and actual diving masks is discussed.
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Date Issued: 1973
PURL: http://purl.flvc.org/fcla/dt/13569
Subject Headings: Acoustic models, Diving
Format: Document (PDF)

Title: ANALYSIS OF FREE VIBRATIONS OF BEAMS WITH VARYING DEGREES OF UNCONSTRAINED VISCOELASTIC DAMPING LAYER COVERAGE.
Creator: DE AGUIAR, JOAO BATISTA., Florida Atlantic University, Dunn, Stanley E.
Abstract/Description: A method of analysis addressing the problem of predicting the performance of beams with viscoelastic damping layer coating of varying degrees of coverage undergoing free vibrations is presented. Results based on this analysis and using mechanical properties of selected materials are generated for five different boundary conditions. The analytical results are verified experimentally for the case of a clamped-free beam. Also the main hypotheses employed in the theoretical approach are verified....
Show moreA method of analysis addressing the problem of predicting the performance of beams with viscoelastic damping layer coating of varying degrees of coverage undergoing free vibrations is presented. Results based on this analysis and using mechanical properties of selected materials are generated for five different boundary conditions. The analytical results are verified experimentally for the case of a clamped-free beam. Also the main hypotheses employed in the theoretical approach are verified. Finally, an analysis of the results leads to a discussion of the dynamic properties of coated beams.
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Date Issued: 1982
PURL: http://purl.flvc.org/fcla/dt/14097
Subject Headings: Viscoelasticity, Girders--Vibration
Format: Document (PDF)

Title: ACOUSTIC EMISSIONS TESTING AS A NONDESTRUCTIVE MONITOR OF CONCRETE CRACKING DUE TO REINFORCING BAR CORROSION.
Creator: YOUNG, JAMES DANIEL., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Steel reinforced concrete specimens of loaded and unloaded configuration were placed in contact with seawater in a state of accelerated corrosion. They were simultaneously monitored for acoustic emission and the results were analyzed in an evaluation of the use of acoustic emission as a nondestructive monitor of corrosion induced cracking. It was shown that, in a laboratory environment, counts and amplitude information are sensitive indicators of the levels of cracking within the concrete...
Show moreSteel reinforced concrete specimens of loaded and unloaded configuration were placed in contact with seawater in a state of accelerated corrosion. They were simultaneously monitored for acoustic emission and the results were analyzed in an evaluation of the use of acoustic emission as a nondestructive monitor of corrosion induced cracking. It was shown that, in a laboratory environment, counts and amplitude information are sensitive indicators of the levels of cracking within the concrete specimen; and thereby the degree of corrosion damage may be inferred. Analytical models applicable to the representation of acoustic emission amplitude distribution are discussed also.
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Date Issued: 1982
PURL: http://purl.flvc.org/fcla/dt/14141
Subject Headings: Reinforced concrete--Cracking, Reinforced concrete--Corrosion, Acoustic emission testing
Format: Document (PDF)

Title: ACOUSTIC EMISSION ASSOCIATED WITH EMBEDDED METAL CORROSION IN A CONCRETE SLAB.
Creator: MARSHALL, RICHARD MELBOURNE., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Measured values of attenuation with distance, amplitude distribution, and propagation velocity of acoustic emissions associated with embedded metcil corrosion induced cracking in a concrete slab are presented. An extensive review of acoustic emission signal processing techniques and theoretical background material is also included. The study points out how attenuation and propagation velocity of the acoustic emission signal affects various signal processing techniques and verifies an...
Show moreMeasured values of attenuation with distance, amplitude distribution, and propagation velocity of acoustic emissions associated with embedded metcil corrosion induced cracking in a concrete slab are presented. An extensive review of acoustic emission signal processing techniques and theoretical background material is also included. The study points out how attenuation and propagation velocity of the acoustic emission signal affects various signal processing techniques and verifies an amplitude distribution spreading rrodel. The need for further defirlition of attentuation values caused by fluid loading of the concrete surface is also discussed.
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Date Issued: 1982
PURL: http://purl.flvc.org/fcla/dt/14129
Subject Headings: Reinforced concrete--Corrosion, Acoustic emission testing
Format: Document (PDF)

Title: Efficiency analysis and prototyping of a buoyancy-powered underwater glider.
Creator: Williams, Douglas Bartlett., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Limited development of buoyancy powered underwater vehicles has occurred with little analysis of the efficiency of this form of propulsion. A nondimensional method of analysis of the propulsion efficiency of these vehicles has been developed. A dimensional analysis was conducted by applying the nondimensional propulsion efficiency to the analysis of vehicles with various hull and wing sizes. Propulsion efficiencies of 70% to 75% were found to be obtainable with existing wing designs. A...
Show moreLimited development of buoyancy powered underwater vehicles has occurred with little analysis of the efficiency of this form of propulsion. A nondimensional method of analysis of the propulsion efficiency of these vehicles has been developed. A dimensional analysis was conducted by applying the nondimensional propulsion efficiency to the analysis of vehicles with various hull and wing sizes. Propulsion efficiencies of 70% to 75% were found to be obtainable with existing wing designs. A prototype was designed and built using the relationships between actual hull and wing size obtained from the dimensional analysis. This prototype was tested at sea to determine the accuracy of the prediction of performance of an underwater glider. These tests showed that the method of buoyancy propulsion is both predictable and reliable when applied to an underwater glider.
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Date Issued: 2000
PURL: http://purl.flvc.org/fcla/dt/15784
Subject Headings: Gliders (Aeronautics), Prototypes, Engineering
Format: Document (PDF)

Title: DETERMINATION OF VISCOELASTIC MATERIAL PROPERTIES USING TWO-DIMENSIONAL PLATE TESTING.
Creator: UHLAR, DAVID ANDREW., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A method of analysis is presented which employs a two-dimensional plate test to determine the dynamic modulus of elasticity and loss factor of viscoelastic damping materials. This method is based on an energy approach to the free vibration of plates. The results derived from the two-dimensional plate test procedure are compared to values from conventional beam tests. This comparison indicates that the material properties determined from the plate test method are in good agreement with values...
Show moreA method of analysis is presented which employs a two-dimensional plate test to determine the dynamic modulus of elasticity and loss factor of viscoelastic damping materials. This method is based on an energy approach to the free vibration of plates. The results derived from the two-dimensional plate test procedure are compared to values from conventional beam tests. This comparison indicates that the material properties determined from the plate test method are in good agreement with values determined from the beam test method. Thus, the dynamic modulus of elasticity and loss factor of viscoelastic damping materials can be determined from either beam or plate tests and these values can be used in the two-dimensional plate equations to evaluate the effectiveness of the damping material. In light of this study, it is suggested that beam tests be performed to derive viscoelastic material properties because of the simplicity of the beam test procedure compared to that of the plate test procedure.
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Date Issued: 1982
PURL: http://purl.flvc.org/fcla/dt/14096
Subject Headings: Elastic plates and shells, Viscoelasticity
Format: Document (PDF)

Title: DETECTION OF DETERIORATION OF REINFORCED CONCRETE BY ACOUSTIC EMISSION TECHNIQUES.
Creator: WENG, MING-YUAN., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In this investigation acoustic emission techniques were employed to detect deterioration of reinforced concrete. As a result of various laboratory tests, acoustic emission activity was found to be due to development of cracking only. Acoustic emission techniques were able to locate cracks in a specimen by linear location. Various acoustic emission parameters such as amplitude, signal shape and frequency were also analyzed and discussed. It was concluded that acoustic emission techniques...
Show moreIn this investigation acoustic emission techniques were employed to detect deterioration of reinforced concrete. As a result of various laboratory tests, acoustic emission activity was found to be due to development of cracking only. Acoustic emission techniques were able to locate cracks in a specimen by linear location. Various acoustic emission parameters such as amplitude, signal shape and frequency were also analyzed and discussed. It was concluded that acoustic emission techniques provided a feasible method for detection of deterioration and cracking of steel reinforced structures in laboratory studies as well as in a field environment.
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Date Issued: 1980
PURL: http://purl.flvc.org/fcla/dt/14042
Subject Headings: Acoustic emission testing, Reinforced concrete--Corrosion
Format: Document (PDF)

Title: Damage detection for autonomous underwater vehicles.
Creator: Rae, Graeme John Stuart., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A method of on-line monitoring AUV onboard systems is described. This algorithm determines deviations from normal operating conditions based on a damage level calculated from recursive least squares system identification performed on the system under consideration, followed by a gradient detection technique which extracts significant changes in identified model parameters System damage types are characterized together with likely system responses to such failures. Extensive testing of the...
Show moreA method of on-line monitoring AUV onboard systems is described. This algorithm determines deviations from normal operating conditions based on a damage level calculated from recursive least squares system identification performed on the system under consideration, followed by a gradient detection technique which extracts significant changes in identified model parameters System damage types are characterized together with likely system responses to such failures. Extensive testing of the algorithm is performed using several simulated AUV on-board systems undergoing different types of failures while carrying out different mission scenarios.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/12331
Subject Headings: Submersibles--Automatic control, Fault-tolerant computing, Algorithms--Data procedssing
Format: Document (PDF)

Title: Basic design and performance analysis of an inertial navigation system for an autonomous underwater vehicle.
Creator: Khedkar, Amol C., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The parameters underlying the design of an Inertial Navigation System (INS) for an Autonomous Underwater Vehicle (AUV) are studied. The strapdown approach for this design is discussed. The performance of a mathematical model of an INS is investigated using a simulation program developed for this purpose. An algorithm is outlined for investigating the accuracy of the computed position of an AUV as compared to the actual or expected position. The results of the simulation program developed...
Show moreThe parameters underlying the design of an Inertial Navigation System (INS) for an Autonomous Underwater Vehicle (AUV) are studied. The strapdown approach for this design is discussed. The performance of a mathematical model of an INS is investigated using a simulation program developed for this purpose. An algorithm is outlined for investigating the accuracy of the computed position of an AUV as compared to the actual or expected position. The results of the simulation program developed using the above mentioned algorithm are presented in a graphical form. The Ring Laser Gyro (RLG), a recent development in the field of inertial sensor technology, is studied with reference to possible use in an INS for an AUV.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14535
Subject Headings: Remote submersibles
Format: Document (PDF)

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.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14289
Subject Headings: Acoustic radiation pressure, Vibration--Measurement
Format: Document (PDF)

Title: VIBRATION ANALYSIS OF RECTANGULAR PLATES UNDER FLUID LOADING.
Creator: LEE, TZER CHIA., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: An energy method is presented for predicting the natural frequencies, radiation loss factor and system loss factor of simply supported rectangular plates under fluid loading. Both bare plates and plates with complete damping treatments are considered. Results obtained using the method developed are compared with two other theories. The agreement is generally good. The study points out the need for detailed analyses of plate vibration patterns and their associated radiation output under...
Show moreAn energy method is presented for predicting the natural frequencies, radiation loss factor and system loss factor of simply supported rectangular plates under fluid loading. Both bare plates and plates with complete damping treatments are considered. Results obtained using the method developed are compared with two other theories. The agreement is generally good. The study points out the need for detailed analyses of plate vibration patterns and their associated radiation output under various plate boundary conditions. There also exists a need for carefully conducted experimental work to verify the applicability of the current theory.
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Date Issued: 1981
PURL: http://purl.flvc.org/fcla/dt/14086
Subject Headings: Plates (Engineering)--Vibration
Format: Document (PDF)

Title: Simulation, control and optimization of underwater vehicle performance.
Creator: Zipf, David Glenn., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This project addresses the simulation, control and optimization of underwater vehicle performance. An analytical model of underwater vehicle motion has been developed. This model is based on a set of six degree of freedom nonlinear differential equations of motion. These equations incorporate inertial, hydrodynamic, hydrostatic, gravity and thruster forces to define the vehicle's motion. The forces are calculated and the equations of motion solved using a finite difference method of...
Show moreThis project addresses the simulation, control and optimization of underwater vehicle performance. An analytical model of underwater vehicle motion has been developed. This model is based on a set of six degree of freedom nonlinear differential equations of motion. These equations incorporate inertial, hydrodynamic, hydrostatic, gravity and thruster forces to define the vehicle's motion. The forces are calculated and the equations of motion solved using a finite difference method of integration. An automatic closed loop control strategy has been developed and integrated into the motion model. The controller determines control plane deflection and thruster output based on sensor provided input, maneuver request and control gain constants. The motion model simulates the effects of these controller requests on the vehicle motion. The controller effects are analyzed and an optimal set of control gains is determined. These optimal gains are determined based on a quantitative comparison of a pre-defined Performance Index (PI) function. The PI is a function of critical performance values, i.e., energy consumption, and user defined weighted constants. By employing an iteration technique the PI is minimized to provide an optimal set of control gains.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14534
Subject Headings: Oceanographic submersibles--Automatic control, Oceanographic submersibles--Simulation methods, Vehicles, Remotely piloted
Format: Document (PDF)

Title: THE APPLICATION OF THE ENERGY ACCOUNTANCY EQUATION IN THE INVESTIGATION OF ENERGY TRANSFER IN A THIN WALLED SHELL STRUCTURE.
Creator: SCHAPLEY, RAMON FRANK, II., 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 Accountancy method is used to describe the response of a system by accounting for the various energy components in a system, that is components describing the input energy, the energy dissipated, and the energy transfered by the system. These components are functions of quantities that can be determined either through measurement or finite element analysis of the system. This concept is used in this study to determine the response of a small diameter pipe containing two different...
Show moreThe Energy Accountancy method is used to describe the response of a system by accounting for the various energy components in a system, that is components describing the input energy, the energy dissipated, and the energy transfered by the system. These components are functions of quantities that can be determined either through measurement or finite element analysis of the system. This concept is used in this study to determine the response of a small diameter pipe containing two different fluids, air and water. The results of this study have shown that the Snergy Accountancy method can be used to describe the response of a thin walled shell structure with good results. It has also been shown in this study that in small diameter pipes the fluid contained by the system can be considered to act as a reactive medium in the response of the structure.
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Date Issued: 1985
PURL: http://purl.flvc.org/fcla/dt/14277
Subject Headings: Force and energy--Analysis, Force and energy--Measurement
Format: Document (PDF)

Acoustic emission testing (4)	+ -
Reinforced concrete--Corrosion (3)	+ -
Viscoelasticity (2)	+ -
Acoustic models (1)	+ -
Acoustic radiation pressure (1)	+ -

Algorithms--Data procedssing (1)	+ -
Diving (1)	+ -
Elastic plates and shells (1)	+ -
Fault-tolerant computing (1)	+ -
Force and energy--Analysis (1)	+ -
Force and energy--Measurement (1)	+ -
Girders--Vibration (1)	+ -
Gliders (Aeronautics) (1)	+ -
Oceanographic submersibles--Automatic control (1)	+ -
Oceanographic submersibles--Simulation methods (1)	+ -
Plates (Engineering)--Vibration (1)	+ -
Prestressed concrete (1)	+ -
Prototypes, Engineering (1)	+ -
Reinforced concrete--Cracking (1)	+ -
Remote submersibles (1)	+ -
Sound analyzers--Research (1)	+ -
Spectrum analysis--Research (1)	+ -
Submersibles--Automatic control (1)	+ -
Vehicles, Remotely piloted (1)	+ -
Vibration--Measurement (1)	+ -

Dunn, Stanley E. (15)	+ -
Florida Atlantic University (15)	+ -
College of Engineering and Computer Science (11)	+ -
Department of Ocean and Mechanical Engineering (11)	+ -
Cuschieri, Joseph M. (2)	+ -

BABAKANIAN, RUBIK. (1)	+ -
BULLWINKEL, PAUL EDWARD. (1)	+ -
CZARNECKI, MICHAEL. (1)	+ -
DE AGUIAR, JOAO BATISTA. (1)	+ -
Khedkar, Amol C. (1)	+ -
LEE, TZER CHIA. (1)	+ -
MAILLET, PHILIPPE LOUIS. (1)	+ -
MARSHALL, RICHARD MELBOURNE. (1)	+ -
Rae, Graeme John Stuart. (1)	+ -
SCHAPLEY, RAMON FRANK, II. (1)	+ -
UHLAR, DAVID ANDREW. (1)	+ -
WENG, MING-YUAN. (1)	+ -
Williams, Douglas Bartlett. (1)	+ -
YOUNG, JAMES DANIEL. (1)	+ -
Zipf, David Glenn. (1)	+ -

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