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- Title
- A PLANE RECTANGULAR ANISOTROPIC FINITE ELEMENT IN BENDING.
- Creator
- DADE, JOHN THOMAS., Florida Atlantic University, Brannock, Robert N., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
A stiffness matrix of a finite element for a plane rectangular panel capable of resisting transverse loads and which may exhibit in-plane Hookean anisotropy is derived for use in structural analysis. A transverse deflection function is selected which is definable in terms of twelve parameters. The Principle of Virtual Work provides the relationship between forces and displacements by which the desired stiffness matrix is developed. Three displacements at each corner of the element yield...
Show moreA stiffness matrix of a finite element for a plane rectangular panel capable of resisting transverse loads and which may exhibit in-plane Hookean anisotropy is derived for use in structural analysis. A transverse deflection function is selected which is definable in terms of twelve parameters. The Principle of Virtual Work provides the relationship between forces and displacements by which the desired stiffness matrix is developed. Three displacements at each corner of the element yield twelve governing parameters. The energy method from the theory of elasticity is used to derive the expression for total strain energy in terms of the element's dimensions and the twelve governing parameters. The matrix is checked by principles of continuity and a rigid body displacement.
Show less - Date Issued
- 1972
- PURL
- http://purl.flvc.org/fcla/dt/13476
- Subject Headings
- Engineering, Civil
- Format
- Document (PDF)
- Title
- CRACKING OF CONCRETE DUE TO CORROSION OF VARIOUS EMBEDDED METALS.
- Creator
- TURNER, DEAN HUDSON., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The objective of this investigati.on was to contribute to the determination of a suitable metallic coating for steel reinforcement in concrete exposed to a marine environment and possibly to stray current. Concrete specimens embedded with steel, aluminum, cadmium, copper, molybdenum, nickel, and galvanized steel were exposed to sea water. Direct current was impressed on these to accelerate corrosion of the reinforcement so that cracking of the concrete could be observed within the time limit...
Show moreThe objective of this investigati.on was to contribute to the determination of a suitable metallic coating for steel reinforcement in concrete exposed to a marine environment and possibly to stray current. Concrete specimens embedded with steel, aluminum, cadmium, copper, molybdenum, nickel, and galvanized steel were exposed to sea water. Direct current was impressed on these to accelerate corrosion of the reinforcement so that cracking of the concrete could be observed within the time limit of the investigation. Aluminum, cadmium, copper, and nickel were found to have no beneficial effect on concrete cracking as compared to steel. In addition, no correlation between oxide-metal volume ratio and concrete time-to-cracking could be observed. It was found that corrosion of molybdenum has little or no tendency to crack concrete and its corrosion potential and active behavior approximates that of steel, indicating it may be an excellent coating.
Show less - Date Issued
- 1976
- PURL
- http://purl.flvc.org/fcla/dt/13820
- Subject Headings
- Reinforced concrete--Cracking, Underwater concrete construction, Reinforced concrete--Corrosion
- Format
- Document (PDF)
- Title
- CORROSION OF CONCRETE COVERED REINFORCING STEEL IN A MARINE ENVIRONMENT RESULTING FROM STRAY CURRENT AND GALVANIC COUPLING.
- Creator
- MILLER, RONALD LAWRENCE., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
It is recognized that reinforced concrete structures are often susceptible to stray current corrosion damage. Experiments have been performed upon a reinforced concrete bridge model in sea water, and these indicate that 0.01 percent of stray direct current in this electrolyte may enter the structure. Alternating current may also contribute to corrosion of reinforcing steel, though experimental results reveal detection to be more difficult than for direct current. Two other sources of current...
Show moreIt is recognized that reinforced concrete structures are often susceptible to stray current corrosion damage. Experiments have been performed upon a reinforced concrete bridge model in sea water, and these indicate that 0.01 percent of stray direct current in this electrolyte may enter the structure. Alternating current may also contribute to corrosion of reinforcing steel, though experimental results reveal detection to be more difficult than for direct current. Two other sources of current in reinforcing steel are from cathodic protection systems of utility attachments and from galvanic coupling of the covered steel and bare steel. Mechanisms by which the above types of current contribute to deterioration of reinforced concrete structures are discussed.
Show less - Date Issued
- 1976
- PURL
- http://purl.flvc.org/fcla/dt/13772
- Subject Headings
- Steel--Corrosion
- Format
- Document (PDF)
- Title
- AN EXPERIMENTAL STUDY OF BIOFOULING ON A FLAT PLATE SUSPENDED IN A UNIFORM FLOW.
- Creator
- WOOD, MARK ALAN., Florida Atlantic University, Tennant, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
An investigation was conducted to determine the relationship between hydrodynamic boundary layer parameters and biofouling growth rates. A summary of previous investigations of hydrodynamic effects on biofouling is presented. Wall shear stress is shown to be an important parameter and is described in detail. A submersible water tunnel was designed to allow investigation of a flat plate subject to a uniform flow of seawater. Parallel flow past a flat plate with a laminar boundary layer was...
Show moreAn investigation was conducted to determine the relationship between hydrodynamic boundary layer parameters and biofouling growth rates. A summary of previous investigations of hydrodynamic effects on biofouling is presented. Wall shear stress is shown to be an important parameter and is described in detail. A submersible water tunnel was designed to allow investigation of a flat plate subject to a uniform flow of seawater. Parallel flow past a flat plate with a laminar boundary layer was used to ensure that experimental conditions existed in which a known wall shear stress distribution was establised. Tests were conducted off Virginia Key in Miami, Florida. The results of the experiments clearly indicate the existance of a threshold value of shear stress which inhibits the attachment of the macrofouler under study, the acorn barnacle (Balanus spp.). Reported growth rates from other investigations are presented to substantiate results. Recommendations are made for additional hydrodynamic investigations in dealing with biofouling.
Show less - Date Issued
- 1977
- PURL
- http://purl.flvc.org/fcla/dt/13849
- Subject Headings
- Fouling, Hydrodynamics
- Format
- Document (PDF)
- Title
- STRESS CORROSION CRACKING OF 7079-T651 ALUMINUM IN RESPONSE TO A CONSTANT STRESS INTENSITY.
- Creator
- SCOTT, DARWIN HAROLD, II., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Double cantilever beam specimens of 7079-T651 aluminum were subjected to low constant stress intensities in a sea water environment to determine the stress corrosion cracking response. In addition to a constant stress intensity some specimens were subjected to controlled, constant potentials. Despite the fact that all tests were in Region I of the crack growth rate-stress intensity curve, where the former has been projected to be very dependent upon the latter, a unique relationship between...
Show moreDouble cantilever beam specimens of 7079-T651 aluminum were subjected to low constant stress intensities in a sea water environment to determine the stress corrosion cracking response. In addition to a constant stress intensity some specimens were subjected to controlled, constant potentials. Despite the fact that all tests were in Region I of the crack growth rate-stress intensity curve, where the former has been projected to be very dependent upon the latter, a unique relationship between stress intensity and crack growth rate was not always indicated. Therefore, some variable other than stress intensity is assumed to control crack growth, particularly for the first several hundred hours of exposure. The observed behavior is discussed in terms of accepted theories of stress corrosion cracking in high strength aluminum alloys, including electrochemical dissolution and hydrogen embrittlement.
Show less - Date Issued
- 1977
- PURL
- http://purl.flvc.org/fcla/dt/13878
- Subject Headings
- Stress corrosion, Aluminum--Corrosion
- Format
- Document (PDF)
- Title
- A TURBULENCE CURRENT METER DESIGN, CONSTRUCTION AND USE.
- Creator
- KIDERA, EDWARD HENRY, IV., Florida Atlantic University, Tennant, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The objectives of this investigation were - 1) design and build a turbulence current meter capable of measuring velocity fluctuations in a geophysical scale flow and 2) the measurement of such flow including subsequent analysis of near bottom turbulence. An unique device capable of sensing velocity fluctuations in the region 25cm above the bottom was constructed based on concepts original to the study of turbulence. A review of previous equipment and research is included for a comparison. The...
Show moreThe objectives of this investigation were - 1) design and build a turbulence current meter capable of measuring velocity fluctuations in a geophysical scale flow and 2) the measurement of such flow including subsequent analysis of near bottom turbulence. An unique device capable of sensing velocity fluctuations in the region 25cm above the bottom was constructed based on concepts original to the study of turbulence. A review of previous equipment and research is included for a comparison. The instrument's usefulness was illustrated in the open channel flow of a tidal estuary by its ability to detect the horizontal velocity field. The data obtained for the turbulence shows large variation in velocity of the lateral component on the order of 50-75% of the "mean" current speed. Digital filtering of the data reveals distinct structures of high energy, intermittent in their nature and analogous to "bursting". The energy spectrum of the longitudinal component follows the predicted slope of -1 for over two decades (.01 to 1.3 + Hz).
Show less - Date Issued
- 1978
- PURL
- http://purl.flvc.org/fcla/dt/13943
- Subject Headings
- Turbulence--Measurement, Water current meters
- Format
- Document (PDF)
- Title
- APPLICATION OF A MICROPROCESSOR TO ACOUSTIC DATA SAMPLING AND MANAGEMENT TASKS (AS APPLIED TO MANGANESE NODULE MINING).
- Creator
- MURPHY, DAVID PAUL, JR., Florida Atlantic University, Davidson, J. Blaine, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Methods of collecting information about the deep ocean sediments are considered. A compact, flexible data collection and management system based on microprocessor technology is developed. The hardware of the system is detailed and a typical software operating system is presented which controls sensor operations, stores temporary data and communicates with a shipboard computer system.
- Date Issued
- 1979
- PURL
- http://purl.flvc.org/fcla/dt/13987
- Subject Headings
- Microprocessors, Marine sediments--Sampling, Manganese nodules
- Format
- Document (PDF)
- Title
- THE STEP RECOVERY DIODE WITH APPLICATIONS AS A FREQUENCY MULTIPLIER.
- Creator
- STROBEL, RUSSELL ALAN., Florida Atlantic University, Gazourian, Martin G., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Portable UHF transceivers typically require minimal current drain frequency converters to multiply the frequencies generated by crystal controlled oscillators up to the UHF band. The step recovery diode (SRD) provides an approach to frequency multiplication that requires no d.c. bias and hence minimizes battery drain. This thesis compares the SRD to the more conventional varactor and analyzes SRD device physics and characteristics. SRD operation is explained in terms of the conduction and...
Show morePortable UHF transceivers typically require minimal current drain frequency converters to multiply the frequencies generated by crystal controlled oscillators up to the UHF band. The step recovery diode (SRD) provides an approach to frequency multiplication that requires no d.c. bias and hence minimizes battery drain. This thesis compares the SRD to the more conventional varactor and analyzes SRD device physics and characteristics. SRD operation is explained in terms of the conduction and depletion intervals. The rapid transition from the conduction to the depletion mode allows the SRD to generate high order harmonics of the input frequency. A step-by-step design procedure for a series mode frequency multiplier is presented and empirical observations are used to help explain multiplier operation. The jump phenomena and hysteresis effects previously unexplained in relation to SRD multipliers are explored. Finally, it is shown that the SRD can function as a parametric amplifier.
Show less - Date Issued
- 1979
- PURL
- http://purl.flvc.org/fcla/dt/13970
- Subject Headings
- Diodes, Switching, Diodes, Semiconductor
- 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.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14042
- Subject Headings
- Acoustic emission testing, Reinforced concrete--Corrosion
- Format
- Document (PDF)
- Title
- A BED-LOAD TRANSPORT MEASURING DEVICE.
- Creator
- WU, MUO-CHUNG., Florida Atlantic University, Tennant, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The objectives of this investigation were: (1) to find the relationship between the sand movement velocity and the force induced using a small model basin, (2) to find and build a sand transport meter and apply the relation from (1) together to measure the velocity fluctuation and quantity of sand movement on the beach. The idea of model basin comes from the fluidized bed concept. Using this model, the complicated influences that happen during the field measurement can be prevented, and a...
Show moreThe objectives of this investigation were: (1) to find the relationship between the sand movement velocity and the force induced using a small model basin, (2) to find and build a sand transport meter and apply the relation from (1) together to measure the velocity fluctuation and quantity of sand movement on the beach. The idea of model basin comes from the fluidized bed concept. Using this model, the complicated influences that happen during the field measurement can be prevented, and a prime relation can be applied to the field measurement. In the model basin experiment, the force induced by the drag is related to the velocity of power around 0. 62. In the field measurement on the beach, the initial goal could not be reached because of the appearance of the unexpected low frequency signal which was initiated by the wave motion itself. However, the device and idea of this experlment were proven to be good and feasible.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14021
- Subject Headings
- Bed load--Measurement
- Format
- Document (PDF)
- Title
- A PRELIMINARY STUDY OF WEAR OF AISI TYPE 304 STAINLESS STEEL AND MILD STEEL IN SEA WATER.
- Creator
- WENG, HARVEY H. L., Florida Atlantic University, Stevens, Karl K., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
A fatigue machine was rebuilt to investigate the wear of mild steel and AISI Type 304 stainless steel while undergoing cyclic relative motions in air and sea water environments. Wear curves were obtained for both materials by measuring specimen weight loss as a function of the number of cycles of relative motion, and surface damage of the specimens was photographed. The results indicate that a sea water environment has a strong influence upon the wear characteristics of mild steel and 304...
Show moreA fatigue machine was rebuilt to investigate the wear of mild steel and AISI Type 304 stainless steel while undergoing cyclic relative motions in air and sea water environments. Wear curves were obtained for both materials by measuring specimen weight loss as a function of the number of cycles of relative motion, and surface damage of the specimens was photographed. The results indicate that a sea water environment has a strong influence upon the wear characteristics of mild steel and 304 stainless steel. For the mild steel, the corrosive effects of the sea water contributed to severe pitting and cracking of the wear surface and resulted in a significant increase in wear; after approximately 2.5 million cycles the amount of wear in sea water was approximately three times that in air. For the stainless steel, the sea water acted primarily as a lubricant and coolant, and served to reduce the amount of wear after 2.5 million cycles to about one-tenth of that in air.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14031
- Subject Headings
- Steel--Fatigue--Environmental aspects, Steel, Stainless--Fatigue--Environmental aspects
- Format
- Document (PDF)
- Title
- THE DESIGN OF HIGH FREQUENCY OSCILLATORS: NOISE CHARACTERIZATION, DESIGN THEORY, AND MEASUREMENTS.
- Creator
- VICTOR, ALAN MICHAEL., Florida Atlantic University, Gazourian, Martin G., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
A design theory for high frequency oscillators is presented. Emphasis is placed on oscillator design techniques which are applicable to the electrical tuning of LC and transmission line resonators. Attention is paid to design approaches which yield an oscillator with high spectral purity and a large signal to noise ratio. Theory and measurements demonstrate for the oscillator configurations investigated the a small L/C ratio is desirable for improved oscillator signal to noise ratio....
Show moreA design theory for high frequency oscillators is presented. Emphasis is placed on oscillator design techniques which are applicable to the electrical tuning of LC and transmission line resonators. Attention is paid to design approaches which yield an oscillator with high spectral purity and a large signal to noise ratio. Theory and measurements demonstrate for the oscillator configurations investigated the a small L/C ratio is desirable for improved oscillator signal to noise ratio. Equations are developed which define the noise figure the oscillator due to the additive noise of the active device. This analysis demonstrates the need for a high device starting transconductance which should be subsequently reduced during oscillation to minimize the device noise contribution. A relationship is developed between the receiver dynamic range and the oscillator signal to the noise ratio. Oscillator designs in the region 20 Mhz - 200 Mhz verify the analysis. A unified approach to large signal oscillator design is investigated and relationships to oscillator signal to noise ratio using the previously developed theory are noted
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14043
- Subject Headings
- Oscillators, Audio-frequency
- Format
- Document (PDF)
- Title
- STATIC STRESS ANALYSIS OF CHAIN LINKS USING A FINITE-ELEMENT METHOD.
- Creator
- TSENG, HUAN-SHOO HANS., Florida Atlantic University, Stevens, Karl K., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
A static stress analysis of a common chain link and a pear-shaped nng ivas performed using the finite element structural analysis program SAP IV. The required finite element mesh and loading inputs were generated by the pre-processing program PRE-SAP- LINK. This procedure was used to determine the midplane stresses and displacements in a link and ring of typical sizes and subject to concentrated fcrces. Stress distributions and displacements were drawn by hand and by using a Tektronix 4662...
Show moreA static stress analysis of a common chain link and a pear-shaped nng ivas performed using the finite element structural analysis program SAP IV. The required finite element mesh and loading inputs were generated by the pre-processing program PRE-SAP- LINK. This procedure was used to determine the midplane stresses and displacements in a link and ring of typical sizes and subject to concentrated fcrces. Stress distributions and displacements were drawn by hand and by using a Tektronix 4662 Interactive Digital Plotter, respectively. The results obtained show that for both link and ring, the numerically largest principal stress and maximum in-plane shear stress occur on the element directly under an applied load . The entire procedure was verified by comparing the results obtained for the common link with experimental results in the literature and with analytical results obtained using a mechanics of materials approach. All of the results were in close agreement.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14023
- Subject Headings
- Stress concentration
- Format
- Document (PDF)
- Title
- INVESTIGATION AND ANALYSIS OF THE DILUTION AND DISPERSION OF WASTEWATER FROM AN OCEAN OUTFALL ON THE CONTINENTAL SHELF.
- Creator
- MURRAY, JAMES BURKE., Florida Atlantic University, Venezia, William A., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Experimental data fr6m a study of the Boca Raton ocean outfall on December 16, 1980 is presented. A vertical plane near the outfall was mapped using a Neil Brown CTD; a horizontal plane at a depth of one meter was profiled with a towed instrument platform housing two temperature probes and a fluorometer. The relevance of this data with respect to mathematical modeling is discussed. Coherence analysis of the sensor outputs show that temperature sensors alone cannot be used to reliably map the...
Show moreExperimental data fr6m a study of the Boca Raton ocean outfall on December 16, 1980 is presented. A vertical plane near the outfall was mapped using a Neil Brown CTD; a horizontal plane at a depth of one meter was profiled with a towed instrument platform housing two temperature probes and a fluorometer. The relevance of this data with respect to mathematical modeling is discussed. Coherence analysis of the sensor outputs show that temperature sensors alone cannot be used to reliably map the spreading effluent field.
Show less - Date Issued
- 1981
- PURL
- http://purl.flvc.org/fcla/dt/14064
- Subject Headings
- Ocean outfalls--Florida--Boca Raton
- Format
- Document (PDF)
- Title
- A STRESS CONCENTRATION ANALYSIS OF SELECTED WELDS FROM FATIGUE SPECIMENS USING THE FINITE-ELEMENT METHOD.
- Creator
- NEROLICH, SHAUN MICHAEL., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The stress concentration which exists at the toe of an AWS class 'c' weld has been investigated by means of the finite element method. This type of weld is representative of that specified to join tubular members for offshore structures. Welded fatigue specimens were sectioned and the weld profile described in terms of 1) the weld toe radius (R), 2) the reinforcement angle (e) and 3) the filler metal height QH). A statistical analysis was performed to determine the correlation between R, e...
Show moreThe stress concentration which exists at the toe of an AWS class 'c' weld has been investigated by means of the finite element method. This type of weld is representative of that specified to join tubular members for offshore structures. Welded fatigue specimens were sectioned and the weld profile described in terms of 1) the weld toe radius (R), 2) the reinforcement angle (e) and 3) the filler metal height QH). A statistical analysis was performed to determine the correlation between R, e and H from which it was found that they are independent of each other. By use of the finite element method, trends were established for the effect each parameter has on the stress concentration at the weld toe. Analysis of the effect of undercutting was also perfonned and the results used to offer an explanation why fatigue cracks propagate to failure in some cases and arrest in others.
Show less - Date Issued
- 1981
- PURL
- http://purl.flvc.org/fcla/dt/14069
- Subject Headings
- Offshore structures--Welding, Welded joints--Fatigue
- 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.
Show less - Date Issued
- 1981
- PURL
- http://purl.flvc.org/fcla/dt/14086
- Subject Headings
- Plates (Engineering)--Vibration
- Format
- Document (PDF)
- Title
- A METHOD OF ANALYSIS FOR EVALUATING THE EFFECTIVENESS OF PARTIAL DAMPING LAYER TREATMENTS FOR SQUARE PLATES.
- Creator
- KUNG, CHUN-HUA., Florida Atlantic University, Stevens, Karl K., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
An energy method for predicting the natural frequency and loss factor for square plates with partial and complete coatings is developed. Both simply-supported and edge-fixed bonndary conditions are considered. An impulse testing technique is used to provide an experimental verification of the analysis for the case of an edge-fixed square plate. The analytical and experimental results are in close agreement, and indicate that partial coatings can provide effective damping treatments.
- Date Issued
- 1981
- PURL
- http://purl.flvc.org/fcla/dt/14045
- Subject Headings
- Plates (Engineering)--Vibration, Damping (Mechanics)
- Format
- Document (PDF)
- Title
- FATIGUE CRACK DEVELOPMENT IN CATHODICALLY POLARIZED WELDED STEEL IN SEAWATER.
- Creator
- WEHLING, CHRISTOPHER MARK., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The fatigue crack growth behavior of welded ABS DH32 steel spec~mens cathodically polarized to -1.00 volt (Cu-CuS04) and subjected to bending fatigue of nominal stress + 69 MN/m^2 (+- 10 ksi) in seawater was investigated. Small non-propagating surface cracks with lengths up to 4.93 mm formed in the specimens. There were no s~gns of failure after 36 x 10^6 cycles when the experiment was terminated. Comparison of this test with similar freely corroding and -0.85 volt (Cu-CuS04) tests indicated...
Show moreThe fatigue crack growth behavior of welded ABS DH32 steel spec~mens cathodically polarized to -1.00 volt (Cu-CuS04) and subjected to bending fatigue of nominal stress + 69 MN/m^2 (+- 10 ksi) in seawater was investigated. Small non-propagating surface cracks with lengths up to 4.93 mm formed in the specimens. There were no s~gns of failure after 36 x 10^6 cycles when the experiment was terminated. Comparison of this test with similar freely corroding and -0.85 volt (Cu-CuS04) tests indicated that -1.00 volt (Cu-CuS04) cathodic protection is conducive to arrestment of small fatigue cracks. This suggests that modest cathodic over-protection of steel in seawater may beneficial.
Show less - Date Issued
- 1981
- PURL
- http://purl.flvc.org/fcla/dt/14091
- Subject Headings
- Steel--Fatigue
- 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.
Show less - 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.
Show less - Date Issued
- 1982
- PURL
- http://purl.flvc.org/fcla/dt/14129
- Subject Headings
- Reinforced concrete--Corrosion, Acoustic emission testing
- Format
- Document (PDF)