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Title: STRENGTH AND DURABILITY OF FIBER AND POLYMER-MODIFIED CONCRETE FOR MARINE STRUCTURAL APPLICATIONS.
Creator: NOMIKOS, GEORGE GERASSIMOS., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This thesis presents the experimental and analytical investigation of the fiber (steel, glass and Kevlar), and latex-modified concrete structural members exposed to varying periods of marine environment. The findings indicate superior behavior of fibers in flexure (toughness) and impact. Fibers affect the compressive strength only marginally. Kevlar fibers are more stable in the marine environment compared to steel and glass. The addition of latex significantly improves the durability...
Show moreThis thesis presents the experimental and analytical investigation of the fiber (steel, glass and Kevlar), and latex-modified concrete structural members exposed to varying periods of marine environment. The findings indicate superior behavior of fibers in flexure (toughness) and impact. Fibers affect the compressive strength only marginally. Kevlar fibers are more stable in the marine environment compared to steel and glass. The addition of latex significantly improves the durability characteristics. Endochronic constitutive modeling enables realistic prediction of beam flexural behavior. The smallness of the size and number of specimens tested indicates the need for further experimentation with an increased number of members of larger dimensions.
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Date Issued: 1985
PURL: http://purl.flvc.org/fcla/dt/14258
Subject Headings: Reinforced concrete, Fiber--Environmental testing, Polymer-impregnated concrete--Environmental testing
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.
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Date Issued: 1980
PURL: http://purl.flvc.org/fcla/dt/14023
Subject Headings: Stress concentration
Format: Document (PDF)

Title: Response of secondary systems to seismic excitation.
Creator: HoLung, Joseph Anthony., Florida Atlantic University, Lin, Y. K., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In this dissertation the response of secondary systems to seismic excitation is investigated. A secondary system is a piece of equipment or a lighter appendage to a more massive primary structure which receives external excitations indirectly through its host structure. Assumption of linear behavior for both primary and secondary system is made in most parts in the analysis. Parametric excitations due to vertical ground motion and hysteretic behavior of the primary system under severe loading...
Show moreIn this dissertation the response of secondary systems to seismic excitation is investigated. A secondary system is a piece of equipment or a lighter appendage to a more massive primary structure which receives external excitations indirectly through its host structure. Assumption of linear behavior for both primary and secondary system is made in most parts in the analysis. Parametric excitations due to vertical ground motion and hysteretic behavior of the primary system under severe loading are treated in two separate chapters. A general procedure is first developed to formulate the system of equations for a combined primary-secondary linear system in which secondary systems are attached to a primary system at an arbitrary number of locations. Successive chapters are devoted to studying the effects of different factors on the behavior of a particular type of the combined system; namely, a multi-story primary structure supporting a secondary equipment, idealized as a single-degree-of-freedom linear oscillator. We list the following major findings of this study: (1) The two approximation procedures to calculate the response of a secondary system to seismic excitations developed in this dissertation are accurate and efficient, and can be applied to light or moderately heavy equipments. (2) Parametric studies suggest that greater amplification occurs as an equipment is tuned to lower building modes. (3) The equipment response is sensitive to the equipment mass, damping in the building, and the location of the equipment. (4) Soil compliancy can affect equipment response significantly. A greater number of modes should be employed when soil-structure interaction effects are important. (5) Protective devices between the equipment and the supporting floor of a building can reduce the equipment response by an order of magnitude. In this dissertation we consider cushioning devices constructed of linear, viscoelastic materials. (6) Vertical ground motion and gravity effect can both increase equipment response. (7) If a building is forced into the nonlinear regime due to intense seismic excitations, the equipment response can be quite sensitive to the parameters of the nonlinear model.
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Date Issued: 1988
PURL: http://purl.flvc.org/fcla/dt/11915
Subject Headings: Seismology, Earthquake engineering
Format: Document (PDF)

Title: SPECTRUM FATIGUE ON WELDED STRUCTURAL STEEL UNDER CORROSION AND CATHODIC PROTECTION CONDITIONS.
Creator: YANG, JOE-MING., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The object of this work was to investigate the fatigue performance of 25.4mm thick, butt welded ABS DH-32 steel plate under spectrum loading, which simulated the environmental conditions of the North Sea. Specimens were tested in sea water under different levels of cathodic protection. The results, including the previous freely corroding data, are discussed with regard to the effect of cyclic - frequency, loading history, weld profile and cathodic protection. This study indicated that load...
Show moreThe object of this work was to investigate the fatigue performance of 25.4mm thick, butt welded ABS DH-32 steel plate under spectrum loading, which simulated the environmental conditions of the North Sea. Specimens were tested in sea water under different levels of cathodic protection. The results, including the previous freely corroding data, are discussed with regard to the effect of cyclic - frequency, loading history, weld profile and cathodic protection. This study indicated that load interaction effects are negligible in the present experiments. However, frequency, weld geometry and cathodic protection significantly effect fatigue life.
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Date Issued: 1984
PURL: http://purl.flvc.org/fcla/dt/14207
Subject Headings: Steel, Structural--Fatigue, Steel, Structural--Testing
Format: Document (PDF)

Title: SERVICEABILITY OF REINFORCED CONCRETE BEAMS SUBJECTED TO ACCELERATED CORROSION (ACOUSTIC EMISSION, DAMAGE, REMAINING STRENGTH/LIFE, TESTING).
Creator: TITUS, REJI NINAN K., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Steel reinforced concrete beams were placed in contact with seawater in a state of accelerated corrosion, for varying periods of time. Some of them were simultaneously monitored for acoustic emission and the results were analyzed to evaluate the effectiveness of acoustic emission as a non-destructive monitor of corrosion induced damage. It was shown that, in a laboratory environment, counts are good indicators of the extent of corrosion damage. A review of acoustic emission monitoring...
Show moreSteel reinforced concrete beams were placed in contact with seawater in a state of accelerated corrosion, for varying periods of time. Some of them were simultaneously monitored for acoustic emission and the results were analyzed to evaluate the effectiveness of acoustic emission as a non-destructive monitor of corrosion induced damage. It was shown that, in a laboratory environment, counts are good indicators of the extent of corrosion damage. A review of acoustic emission monitoring techniques and theoretical background is included. The concrete beams were tested for flexural strength after being corroded. Reduction in rebar section was found to have a very good correlation with da mage. An attempt was made to predict remaining life of the beams based on data obtained from the tests.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14310
Subject Headings: Reinforced concrete--Corrosion
Format: Document (PDF)

Title: Thermal response in Florida bridges.
Creator: Sandepudi, Krishna Srinivasa., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Reinforced and prestressed concrete bridges are subjected to non-linear temperature variations leading to complex thermal stresses which vary continuously with time. Though these stresses are often comparable with those produced by live and dead loads, little guidance is given in bridge design codes on how these stresses are accurately computed. The objective of this project is to study the response of Florida bridges in the extreme thermal environment The project is divided into the...
Show moreReinforced and prestressed concrete bridges are subjected to non-linear temperature variations leading to complex thermal stresses which vary continuously with time. Though these stresses are often comparable with those produced by live and dead loads, little guidance is given in bridge design codes on how these stresses are accurately computed. The objective of this project is to study the response of Florida bridges in the extreme thermal environment The project is divided into the following four tasks i) Computer modeling of the bridge and estimation of the thermal response. ii) Field measurements of temperatures in typical bridges. iii) Comparison of observed and estimated data. iv) Suggestions and/or revisions to the existing thermal stress allowances in the code. A computer software FETAB was used to model and analyze the thermal response of several bridge cross sections. Two single cell box girder bridges, located at the 1-595 and US-441 interchange, Fort Lauderdale, were instrumented with thermocouples and vibrating wire strain gages. The predicted temperature variations were found to compare fairly well with those measured in the field. Though the analytical values vary a little from the actual field data, emphasis was given to gain insight into the problems associated with the thermal effects in concrete bridges. Suggestions were made for revision of existing design code provisions for improved design of bridges.
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Date Issued: 1991
PURL: http://purl.flvc.org/fcla/dt/14759
Subject Headings: Bridges, Concrete--Thermal properties, Bridges, Concrete--Effect of temperature on, Thermal stresses
Format: Document (PDF)

Title: Thermal and stress analysis of heterojunction bipolar transistor.
Creator: Rivero, Jose Fernando., Florida Atlantic University, Tsai, Chi-Tay, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The objective of this work is to perform the current induce thermal stress analysis of heterojunction bipolar transistor and to determine the implications of the variation of the thermal shunt thickness. A thesis presented on multi-physics using finite element analysis, covering fluid, thermal and stress with fatigue life analysis of a microelectronic heterojunction bipolar transistor.
Date Issued: 2001
PURL: http://purl.flvc.org/fcla/dt/12834
Subject Headings: Junction transistors, Thermal analysis
Format: Document (PDF)

Title: Theoretical analysis of reinforced and prestressed concrete bridge members strengthened with CFRP laminates.
Creator: Qu, Rong., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Nonlinear finite element analyses of the reinforced rectangular beams, prestressed solid slab and prestressed voided slab retrofitted with CFRP laminates are carried out using the software ANSYS(version 5.0) on the Sunwork station. The computer analyses are based on the proposed stress-strain relationship considering the effects of tensile stress on both elastic modulus and maximum compressive stress of concrete. Several assumptions are made in predicting the loss of tensile strength due to...
Show moreNonlinear finite element analyses of the reinforced rectangular beams, prestressed solid slab and prestressed voided slab retrofitted with CFRP laminates are carried out using the software ANSYS(version 5.0) on the Sunwork station. The computer analyses are based on the proposed stress-strain relationship considering the effects of tensile stress on both elastic modulus and maximum compressive stress of concrete. Several assumptions are made in predicting the loss of tensile strength due to crack, confinement due to the laminate bonding, tensile strength due to the prestress force, failure pattern due to the concentrated stress adjacent to the loading point and concrete crushing due to large compressive strain. A subroutine is developed using macro commands of ANSYS. In this research, Branson's equation or Ie procedure is assumed in the prediction of deflection of retrofitted concrete members. The modifications needed due to laminate bonding are the cracking moments of inertia (Icr) of the beams or slabs bonded with CFRP laminates, which are included in the analysis.
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Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/15083
Subject Headings: ANSYS (Computer system), Reinforced concrete--Plastic properties, Carbon composites, Fiber reinforced plastics, Bridges--Design and construction, Prestressed concrete construction
Format: Document (PDF)

Title: Thermal analysis of a heterojunction bipolar transistor.
Creator: Kokkalera, Subbaiya U., Florida Atlantic University, Tsai, Chi-Tay, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The Heterojunction Bipolar Transistor (HBT) is capable of delivering high current density at microwave frequencies and are now being implemented in microwave circuitry as high power amplifiers. The heat generated during device operation is dissipated through the Gallium Arsenide substrate. Because of its poor thermal conductivity the junction temperature rise can be large enough to degrade and thermally limit the performance of the device. The power HBT with multiple emitter fingers are...
Show moreThe Heterojunction Bipolar Transistor (HBT) is capable of delivering high current density at microwave frequencies and are now being implemented in microwave circuitry as high power amplifiers. The heat generated during device operation is dissipated through the Gallium Arsenide substrate. Because of its poor thermal conductivity the junction temperature rise can be large enough to degrade and thermally limit the performance of the device. The power HBT with multiple emitter fingers are susceptible to the thermal effect due to non-uniform temperature distribution. This results in a thermal effect called thermal runaway causing thermal-induced current instability and hot spot formation thus destroying the device. Thermal shunt technique which has been developed to suppress this non-uniform temperature involves fabrication of a thick metal thermal shunt connecting all the fingers thus forming a strong thermal coupling between the emitter fingers. In this thesis 2 and 3-dimensional thermal simulations were carried out using Finite Element techniques to study the thermal behavior of the HBT's as a function of thermal shunt and other device design configurations such as the number of emitter fingers, thickness of thermal shunt, emitter spacing, Silicon as a substrate material, power variation etc. The results are projected as a design guideline for HBT device.
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Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/15081
Subject Headings: Junction transistors, Thermal analysis, Microwave circuits
Format: Document (PDF)

Title: Thickness and weld profile effects upon the fatigue crack development in sea water.
Creator: Li, Yong., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This research investigated the plate thickness and weld profile effects upon fatigue of structural steel in sea water. Specific attention was focused on the initiation and propagation behavior of fatigue cracks formed at the toe of different profiled welds and varied plate thicknesses. It was shown that the initiation life was reduced as the thickness increased. The improved weld profile increased the crack initiation life. Analysis of the fatigue data indicated that the Initiation Life to...
Show moreThis research investigated the plate thickness and weld profile effects upon fatigue of structural steel in sea water. Specific attention was focused on the initiation and propagation behavior of fatigue cracks formed at the toe of different profiled welds and varied plate thicknesses. It was shown that the initiation life was reduced as the thickness increased. The improved weld profile increased the crack initiation life. Analysis of the fatigue data indicated that the Initiation Life to Failure Life Ratio Ni/Nf appeared to be greater for the improved weld profile than for the AWS Basic weld profile. The improved weld profile prolonged the propagation life Np. The thickness factor influenced the propagation life Np for the improved weld profile, but the trend was uncertain for the basic weld profile.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14532
Subject Headings: Steel, Structural--Fatigue
Format: Document (PDF)

Title: Thermodynamic analysis of the influences of temperature and pressure on deep sea cathodic protection criterion.
Creator: Wang, Weiqing., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Knowledge of the reversible potential for corrosion reaction under condition of deep sea exposure and how this is influenced by parameters such as temperature and pressure is of importance to the understanding and design of deep sea cathodic protection systems, since this potential is used as the cathodic protection criterion. Also, if the polarized potential is more negative than the reversible potential of the hydrogen reaction, then hydrogen embrittlement may occur. Thermodynamic analysis...
Show moreKnowledge of the reversible potential for corrosion reaction under condition of deep sea exposure and how this is influenced by parameters such as temperature and pressure is of importance to the understanding and design of deep sea cathodic protection systems, since this potential is used as the cathodic protection criterion. Also, if the polarized potential is more negative than the reversible potential of the hydrogen reaction, then hydrogen embrittlement may occur. Thermodynamic analysis methods are used to calculate Gibbs free energy change and reversible potential of reactions involved in cathodic protection of steel for temperatures and pressures typical of deep sea. Based on the assumptions employed it is found that the reversible potential for the iron reaction becomes less negative with depth for the first 1000m and remains approximately constant beyond this.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14515
Subject Headings: Steel--Cathodic protection, Seawater--Thermodynamics
Format: Document (PDF)

Title: A STUDY OF THE EFFECT OF FLOW PARAMETERS ON THE CATHODIC PROTECTION OF A STEEL PLATE IN NATURAL SEAWATER.
Creator: MCCABE, KEVIN MICHAEL., Florida Atlantic University, Smith, Samuel W., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The influence of hydrodynamic parameters and cathodic polarization on the formation of calcareous deposits on a steel plate in flowing seawater is investigated. Current density variations on the plate are determined for a combination of applied potentials and seawater velocities. Equations are developed to relate the cathodic current density distribution to variations in hydrodynamic and diffusional boundary layer thickness along the plate for laminar and turbulent flow regimes. A comparison...
Show moreThe influence of hydrodynamic parameters and cathodic polarization on the formation of calcareous deposits on a steel plate in flowing seawater is investigated. Current density variations on the plate are determined for a combination of applied potentials and seawater velocities. Equations are developed to relate the cathodic current density distribution to variations in hydrodynamic and diffusional boundary layer thickness along the plate for laminar and turbulent flow regimes. A comparison of experimental current densities on a bare plate to that predicted by theory is examined. Effects of flow on the formation and properties of calcareous deposits are discussed in light of recent developments in marine cathodic protection.
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Date Issued: 1984
PURL: http://purl.flvc.org/fcla/dt/14192
Subject Headings: Plates, Iron and steel--Cathodic protection, Carbon steel--Corrosion, Plates, Iron and steel--Fluid dynamics, Cathodic protection
Format: Document (PDF)

Title: Sensor based mapping and navigation for underwater robots.
Creator: Scarim, Philip F., Florida Atlantic University, Steer, Barry, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This thesis presents a mapping and navigation system intended for an unmanned untethered underwater vehicle. The system utilizes range data obtained from a time of flight sonar operating at 307KHz. The range data, along with an angle measurement of the transducer, is used to generate a simple object map (detected object and its position in two dimensions). The raw range data is filtered using an edge detection algorithm. The edge detection algorithm extracts possible corners from the acoustic...
Show moreThis thesis presents a mapping and navigation system intended for an unmanned untethered underwater vehicle. The system utilizes range data obtained from a time of flight sonar operating at 307KHz. The range data, along with an angle measurement of the transducer, is used to generate a simple object map (detected object and its position in two dimensions). The raw range data is filtered using an edge detection algorithm. The edge detection algorithm extracts possible corners from the acoustic data of the scanned environment. The output of the edge detection algorithm is sent to a confidence program. The confidence program determines which of the possible "corners", determined by the edge detection algorithm, are "actual" corners. The output of the confidence program is then used to produce the object map. This object map may be used as the input to an annotated map-builder. The output of the confidence program is then input to the navigation system. The navigation system determines the position of the vehicle relative to a detected object without any a-priori information, which may be used as an input to a path planner and an obstacle avoidance system. The experiments were carried out in a 25 x 30 foot pool and the experimental data processed on a Sun Workstation using Matlab and C generated code for post-processing of the raw acoustical data.
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Date Issued: 1996
PURL: http://purl.flvc.org/fcla/dt/15263
Subject Headings: Robots, Underwater navigation
Format: Document (PDF)

Title: Static, fatigue and ultimate load behavior of bridges prestressed with advanced composite materials.
Creator: Sandepudi, Krishna Srinivasa., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: One of the major problems the construction industry faces today is low corrosion resistance of reinforcing and prestressing steel, which significantly affects the durability of concrete structures. Theoretically Advanced Composite Materials (ACM) can successfully be used in concrete structures, in lieu of steel, as reinforcing and/or prestressing elements, owing to high tensile strength, immunity towards corrosion, low Young's modulus, light weight and high fatigue resistance. Very little...
Show moreOne of the major problems the construction industry faces today is low corrosion resistance of reinforcing and prestressing steel, which significantly affects the durability of concrete structures. Theoretically Advanced Composite Materials (ACM) can successfully be used in concrete structures, in lieu of steel, as reinforcing and/or prestressing elements, owing to high tensile strength, immunity towards corrosion, low Young's modulus, light weight and high fatigue resistance. Very little experimental and performance data are available on the properties of ACM and their application in concrete structures. Thus, to ensure safety of the structures, accurate assessment and continuous performance monitoring of the ACM together with the structure have to be made with an option of active and/or passive structural control. This investigation is aimed to establish the feasibility of using Aramid Fiber Reinforced Plastic (AFRP) cables as reinforcing/prestressing elements in concrete bridge structures. Besides investigating the durability of the AFRP cables in adverse environments (alkali and seawater), static and ultimate load tests were performed on a Double-Tee beam and three rectangular beams together with static, fatigue and ultimate load tests on a half scale model Double-Tee bridge system prestressed with AFRP. The AFRP specimens exposed to alkali and seawater for 900 hours retained 88% of the average failure strength of control specimens. Large deformations at ultimate conditions and good fatigue resistance were observed in the experimental studies. A computer code, FRPFLEX, was developed to perform flexural analysis of beams prestressed/reinforced with the ACM. An incremental, stiffness augmented non-linear analysis was performed using grillage analogy to assess static flexural behavior of Double-Tee bridge system. Analytical results showed good correlation with experimental findings. An active deformation/vibration control model is suggested, which can be incorporated in prototype bridges for safety and performance data evaluation. Feasibility of the use of the AFRP cables in bridge structures is assessed based on the experimental and analytical parameters such as deflections, strains, crack distributions, crack widths and energy considerations.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/12414
Subject Headings: Prestressed concrete construction, Steel--Fatigue, Bridges--Fatigue, Fiber reinforced plastics
Format: Document (PDF)

Title: Statistical modeling of the container inventory control in a distribution network.
Creator: Feng, Weiming., Florida Atlantic University, Han, Chingping (Jim), College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The study of the reusable container inventory control in a distribution network is crucial to the efficiency and cost effectiveness of the transportation systems. In order to minimize the total operation cost of such a transportation network system, all subsystems of the distribution network have to be optimized together as a whole system. In this study, we extended the inventory control concept and developed a multiple-inventory control model for the transportation network. We presented a...
Show moreThe study of the reusable container inventory control in a distribution network is crucial to the efficiency and cost effectiveness of the transportation systems. In order to minimize the total operation cost of such a transportation network system, all subsystems of the distribution network have to be optimized together as a whole system. In this study, we extended the inventory control concept and developed a multiple-inventory control model for the transportation network. We presented a systematic approach to address all those subsystems as interrelated systems. Mathematical models were developed for the transportation and container inventory control problems first. Then, the statistical modeling method was used to analyze the effects of the container inventory management policies on the performance of the transportation system. Based on the optimization theory, simulation executions were such arranged to lead to the globe optimality. This makes it possible to optimize the variables of inventory control under different control policies without solving mathematical models. A Simulation Code Generator (SCG) was also developed for a general container inventory control system.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/12525
Subject Headings: Inventory control--Mathematical models, Containerization, Transportation--Mathematical models, Inventory control--Simulation methods
Format: Document (PDF)

Title: THE USE OF COMPUTER SIMULATION TECHNIQUES IN THE DESIGN OF SHIP CHANNEL WIDTH (PORT, HARBOR, TAMPA).
Creator: THOMAS, CLINTON WILLIAM., Florida Atlantic University, Lin, Newman K., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This report presents a detailed approach to the problem of determining expected shipping delays that are caused by inadequate channel width. Data collection and analysis is accomplished for the shipping industry of Tampa Bay, Florida. Historical data and cargo projection are used to develop the expected shipping traffic density and distribution for the year 2000. An overview of a computer model that simulates the shipping traffic and accounts for delays due to channel width is presented. A...
Show moreThis report presents a detailed approach to the problem of determining expected shipping delays that are caused by inadequate channel width. Data collection and analysis is accomplished for the shipping industry of Tampa Bay, Florida. Historical data and cargo projection are used to develop the expected shipping traffic density and distribution for the year 2000. An overview of a computer model that simulates the shipping traffic and accounts for delays due to channel width is presented. A sensitivity analysis performed on the model to determine the effect each input variable has on shipping delays. The results are presented in the form of shipping delay curves for seven types of vessels over a range of channel widths.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14287
Subject Headings: Shipping--Simulation methods, Channels (Hydraulic engineering)--Design and construction--Simulation methods, Shipping--Florida--Tampa Bay
Format: Document (PDF)

Title: THREE-DIMENSIONAL PHOTOELASTIC STRESS ANALYSIS OF A METAL-TO-METAL CONTACT BOLTED FLANGE.
Creator: Mahfuz, Hassan, Florida Atlantic University, Case, Robert O., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Three-dimensional photoelastic stress analysis techniques are used to determine the stress distribution in a metal-to-metal contact bolted flange. The flange belongs to a thin-walled stage support casing of a jet aircraft engine. Of special interest is the state of stress experienced at flange separation due to axial and bending loads during severe in-flight maneuvering. Details of model development, data collection and discussion of results for the stresses in the bolts and in the vicinity...
Show moreThree-dimensional photoelastic stress analysis techniques are used to determine the stress distribution in a metal-to-metal contact bolted flange. The flange belongs to a thin-walled stage support casing of a jet aircraft engine. Of special interest is the state of stress experienced at flange separation due to axial and bending loads during severe in-flight maneuvering. Details of model development, data collection and discussion of results for the stresses in the bolts and in the vicinity of the flange are presented.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14319
Subject Headings: Strains and stresses, Photoelasticity, Materials--Testing
Format: Document (PDF)

Title: Trim analysis by shooting and finite elements and Floquet eigenanalysis by QR and subspace iterations in helicopter dynamics.
Creator: Achar, Nagari Shriranga., Florida Atlantic University, Gaonkar, Gopal H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The trim analysis for the initial state and control inputs that satisfy response periodicity and flight conditions, and the Floquet eigenanalysis for a few largest eigenvalues of the Floquet transition matrix (FTM) are investigated. In the trim analysis, the convergence of Newton iteration is investigated in computing the periodic initial state and control inputs sequentially and in parallel. The trim analysis uses the shooting method and two h-versions of temporal finite element methods, one...
Show moreThe trim analysis for the initial state and control inputs that satisfy response periodicity and flight conditions, and the Floquet eigenanalysis for a few largest eigenvalues of the Floquet transition matrix (FTM) are investigated. In the trim analysis, the convergence of Newton iteration is investigated in computing the periodic initial state and control inputs sequentially and in parallel. The trim analysis uses the shooting method and two h-versions of temporal finite element methods, one based on displacement formulation and the other on mixed formulation of displacements and momenta. In each method, both the sequential and in-parallel schemes are used, and the resulting nonlinear equations are solved by damped Newton iteration with an optimally selected damping parameter. The reliability of damped Newton iteration, including earlier-observed divergence problems, is quantified by the maximum condition number of the Jacobian matrices of the iterative scheme. For illustrative purposes, rigid flap-lag and flap-lag-torsion models based on quasisteady aerodynamics are selected. Demanding trim analysis conditions are included by considering advance ratios or dimensionless flight speeds twice as high as those of current helicopters. Concerning the Floquet eigenanalysis, the feasibility of using the Arnoldi-Saad method, one of the emerging subspace iteration methods, is explored as an alternative to the currently used QR method, which is not economical for partial eigenanalysis. The reliability of the Arnoldi-Saad method is quantified by the eigenvalue condition numbers and the residual errors of the eigenpairs. In the three trim analysis methods, while the optimally selected damping parameter provides almost global convergence, the in-parallel scheme requires much less machine time than the conventional sequential scheme; both schemes have comparable reliability of the Newton iteration without and with damping. The Arnoldi-Saad method takes much less machine time than the QR method with comparable reliability.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/12297
Subject Headings: Helicopters--Dynamics, Helicopters--Handling characteristics, Stability of helicopters--Mathematical models
Format: Document (PDF)

Title: Ultimate load, creep, shrinkage, and reliability studies of a precast single cell segmental bridge with external post-tensioning.
Creator: Murugesh, Ganapathy., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This dissertation is a study of a 1:3.5 scale model of an externally post-tensioned single cell segmental bridge model of the Long Key bridge. The behavior of the bridge system was evaluated in terms of deflections, strains, joint openings, etc. under static and ultimate load conditions. The precast segmental bridge was cast, assembled, and tested at the Department of Ocean Engineering, Florida Atlantic University for AASHTO HS20-44 truck loadings at typical locations. The study addressed the...
Show moreThis dissertation is a study of a 1:3.5 scale model of an externally post-tensioned single cell segmental bridge model of the Long Key bridge. The behavior of the bridge system was evaluated in terms of deflections, strains, joint openings, etc. under static and ultimate load conditions. The precast segmental bridge was cast, assembled, and tested at the Department of Ocean Engineering, Florida Atlantic University for AASHTO HS20-44 truck loadings at typical locations. The study addressed the joint opening behavior and the response of external tendons during service and ultimate load levels. The analytical nonlinear behavior of the bridge upto the ultimate load level has been predicted using a finite element software PCFRAME developed at University of California, Berkeley. Creep and shrinkage strains were predicted using computer program CRACK developed at University of Calgary, Canada. Creep and shrinkage coefficients evaluated from short term tests, were used in predicting the long term behavior. A method for reliability analysis of post-tensioned segmental bridges has also been presented for serviceability and ultimate limit state conditions.
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Date Issued: 1991
PURL: http://purl.flvc.org/fcla/dt/14709
Subject Headings: Precast concrete construction--Testing, Post-tensioned prestressed concrete construction--Testing, Bridges, Concrete--Models
Format: Document (PDF)

Title: Acoustic Tonal and Vector Properties of Red Hind Grouper Vocalizationd.
Creator: Matthews, Cameron Anthony, Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Vertebrates are the most prodigious vocalizing animals in existence, and the most diverse methods of acoustic communication among vertebrates can be found in the ocean. Relatively many teleost fish are gifted with the ability to communicate acoustically, and the family of serranidae often performs this as a function of the swim bladder. Epinephelus Guttatus (E. guttatus), or more commonly the red hind grouper, is equipped with a drum shaped swim bladder acting as a monopole under typical...
Show moreVertebrates are the most prodigious vocalizing animals in existence, and the most diverse methods of acoustic communication among vertebrates can be found in the ocean. Relatively many teleost fish are gifted with the ability to communicate acoustically, and the family of serranidae often performs this as a function of the swim bladder. Epinephelus Guttatus (E. guttatus), or more commonly the red hind grouper, is equipped with a drum shaped swim bladder acting as a monopole under typical ocean conditions. This configuration allows for what is understood to be omnidirectional projection of tones approximately centered between 40 and 440 Hz and spanning anywhere from 40 to 200 Hz of bandwidth and modulation effects based on observed data provided by researchers. Prior studies on many other fish show correlation in acoustic communication profile with length, size and sexual identity. In the red hind, sexual dimorphism leads to an inherent female identity in all juvenile fish which converts to male according to environmental factors, recommending at least consistent organs across both sexes be assumed even if not in use. Much research has been performed on male fish vocalization in terms of spectral content. Communication in fish is a complex multi-modal process, with acoustic communication being important for many of the species, particularly those in the littoral regions of the worlds’ oceans. If identifying characteristics of the red hind vocalization can be isolated based on detection, classification, tracking and localizing methodologies, then these identifying characteristics may indeed lead to passive feature identification that allows for estimation of individual fish mass. Hypotheses based on vector, cyclostationary and classical tonal mechanics are presented for consideration. A battery of test data collection events, applying pre-recorded fish vocalizations to a geolocated undersea sound source were conducted. The results are supplied with the intent of validating hypothesis in a non-expert system manner that shows how a series of biological metrics may be assessed for detection, classification, localization and mass estimation for an individual vocalizing red hind grouper
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004826, http://purl.flvc.org/fau/fd/FA00004826
Subject Headings: Wave-motion, Theory of., Sound production by animals., Fishes--Vocalization., Bioacoustics., Animal communication., Underwater acoustics., Acoustic surface waves.
Format: Document (PDF)

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