Current Search:  Naval architecture (x)

View All Items

  • CSV Spreadsheet
(1 - 9 of 9)
Finite element simulation of composite ship structures under wave loads and slamming loads
Title
Finite element simulation of composite ship structures under wave loads and slamming loads.
Creator
Rahman, Md Hafizur, Mahfuz, Hassan, Graduate College
Date Issued
2013-04-12
PURL
http://purl.flvc.org/fcla/dt/3361345
Subject Headings
Hulls (Naval architecture), Hulls (Naval architecture)--Design and construction
Format
Document (PDF)
Evaluation of orientation and formulation effects on the impedance of naval special hull treatments
Title
Evaluation of orientation and formulation effects on the impedance of naval special hull treatments.
Creator
Mann, Kristina Marie., Florida Atlantic University, Granata, Richard D., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This research used Electrochemical Impedance Spectroscopy (EIS) as a non-destructive technique to evaluate coating performance and determine the electrochemical characteristics of Special Hull Treatments (SHT). The evaluation of the SHT system provided information on its corrosion resistance and cathodic protection-influencing characteristics. The coating's impedance was analyzed while exposed to ambient versus 4.5 MPa pressures and immersion times of 1 to 9 days in seawater. Eleven specimen...
Show moreThis research used Electrochemical Impedance Spectroscopy (EIS) as a non-destructive technique to evaluate coating performance and determine the electrochemical characteristics of Special Hull Treatments (SHT). The evaluation of the SHT system provided information on its corrosion resistance and cathodic protection-influencing characteristics. The coating's impedance was analyzed while exposed to ambient versus 4.5 MPa pressures and immersion times of 1 to 9 days in seawater. Eleven specimen types were evaluated based on coating seam orientation and composition. The data support the conclusion that there was no effect on impedance values and phase shifts due to orientation, formulation, pressure values or immersion time. However, temperature increase above 30° was shown to decrease the impedance values of the SHT specimens.
Show less
Date Issued
2001
PURL
http://purl.flvc.org/fcla/dt/12840
Subject Headings
Hulls (Naval architecture), Impedance spectroscopy
Format
Document (PDF)
Development and experimental testing of an amphibious vehicle
Title
Development and experimental testing of an amphibious vehicle.
Creator
Marquardt, Joseph G., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The development and experimental testing of the DUKW-Ling amphibious vehicle was performed during the first phase of an autonomous amphibious vehicle system development project. The DUKW-Ling is a 1/7th scale model of a cargo transport concept vehicle. The vehicle was tested in the three regions it is required to operate: land, sea and the surf zone region. Vehicle characteristics such as turning radii, yaw rate and velocities were found for different motor inputs on land and water. Also,...
Show moreThe development and experimental testing of the DUKW-Ling amphibious vehicle was performed during the first phase of an autonomous amphibious vehicle system development project. The DUKW-Ling is a 1/7th scale model of a cargo transport concept vehicle. The vehicle was tested in the three regions it is required to operate: land, sea and the surf zone region. Vehicle characteristics such as turning radii, yaw rate and velocities were found for different motor inputs on land and water. Also, because a vehicle navigating the surf zone is a new area of research that lacks experimental data the vehicle was tested in the breaking waves of the surf zone and its motion characteristics were found, as well as the drivetrain forces required to perform this transition. Maneuvering tests provided data that was used to estimate a model for future autonomous control efforts for both land and water navigation.
Show less
Date Issued
2012
PURL
http://purl.flvc.org/FAU/3342208
Subject Headings
Motor vehicles, Amphibious, Design and construction, Naval architecture
Format
Document (PDF)
Seakeeping response of a Surface Effect Ship in near-shore transforming seas
Title
Seakeeping response of a Surface Effect Ship in near-shore transforming seas.
Creator
Kindel, Michael., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Scale model tests are conducted of a Surface Effect Ship in a near-shore developing sea. A beach is built and installed in a wave tank, and a wavemaker is built and installed in the same wave tank. This arrangement is used to simulate developing sea conditions and a 1:30 scale model SES is used for a series of experiments. Pitch and heave measurements are used to investigate the seakeaping response of the vessel in developing seas. The air-cushion pressure and the vessel speed are varied, and...
Show moreScale model tests are conducted of a Surface Effect Ship in a near-shore developing sea. A beach is built and installed in a wave tank, and a wavemaker is built and installed in the same wave tank. This arrangement is used to simulate developing sea conditions and a 1:30 scale model SES is used for a series of experiments. Pitch and heave measurements are used to investigate the seakeaping response of the vessel in developing seas. The air-cushion pressure and the vessel speed are varied, and the seakeeping results are compared as functions of these two parameters. The experiment results show a distinct correlation between the air-cushion pressure and the response amplitude of both pitch and heave. The results of these experiments are compared against results of a computer model of a Surface Effect Ship (SES).
Show less
Date Issued
2012
PURL
http://purl.flvc.org/FAU/3355563
Subject Headings
Naval architecture, Fluid dynamics, Wave motion, Theory of, Ships, Hydrodynamics
Format
Document (PDF)
Thrust Response of a Vectored-Thruster Unmanned Underwater Vehicle
Title
Thrust Response of a Vectored-Thruster Unmanned Underwater Vehicle.
Creator
Ackermann, Lloyd E. J., von Ellenrieder, Karl, Florida Atlantic University
Abstract/Description
Towing tank/water flume experiments are conducted to characterize the dynamics of a Remotely-Piloted Unmanned Underwater Vehicle (RPUUV) propelled by a vectored-thruster system. Force and torque measurements are used to determine the coefficients of drag, lift, yaw-moment and thrust of the vehicle as a function of the vehicle yaw angle and the vectored-thruster rudder angle. Simultaneously, particle Image Velocimetry (PIV) measurements of the propeller inlet flow are also performed to examine...
Show moreTowing tank/water flume experiments are conducted to characterize the dynamics of a Remotely-Piloted Unmanned Underwater Vehicle (RPUUV) propelled by a vectored-thruster system. Force and torque measurements are used to determine the coefficients of drag, lift, yaw-moment and thrust of the vehicle as a function of the vehicle yaw angle and the vectored-thruster rudder angle. Simultaneously, particle Image Velocimetry (PIV) measurements of the propeller inlet flow are also performed to examine the variation of flow conditions at the propeller inlet with rudder angle. The tests are conducted at 0.150 rnls, 0.300 rnls, 0.515 rnls and 0.773 rnls. While the measured drag coefficient is slightly higher than predicted by theory at low Reynolds number (1.44 x10^5 and 2.88 x10^5), the hydrodynamic coefficients data are expected to be useful in predicting the response of vehicles in the field. Additionally, the magnitude of the thrust vector varies nonlinearly with rudder angle and for nonzero rudder angles the thrust vector does not point in the same direction as the thruster axis.
Show less
Date Issued
2007
PURL
http://purl.flvc.org/fau/fd/FA00012500
Subject Headings
Naval architecture, Oceanographic submersibles--Hydrodynamics, Vibration (Marine engineering)
Format
Document (PDF)
caHydrodynamic analysis of flapping foils for the propulsion of near surface under water vehicles using the panel method
Title
caHydrodynamic analysis of flapping foils for the propulsion of near surface under water vehicles using the panel method.
Creator
Bustos, Julia, Ananthakrishnan, Palaniswamy, Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This thesis presents two-dimensional hydrodynamic analysis of flapping foils for the propulsion of underwater vehicles using a source-vortex panel. Using a simulation program developed in MatLab, the hydrodynamic forces (such as the lift and the drag) as well as the propulsion thrust and efficiency are computed with this method. The assumptions made in the analysis are that the flow around a hydrofoil is two-dimensional, incompressible and inviscid. The analysis is first considered for the...
Show moreThis thesis presents two-dimensional hydrodynamic analysis of flapping foils for the propulsion of underwater vehicles using a source-vortex panel. Using a simulation program developed in MatLab, the hydrodynamic forces (such as the lift and the drag) as well as the propulsion thrust and efficiency are computed with this method. The assumptions made in the analysis are that the flow around a hydrofoil is two-dimensional, incompressible and inviscid. The analysis is first considered for the case of a deeply submerged hydrofoil followed by the case where it is located in shallow water depth or near the free surface. In the second case, the presence of the free surface and wave effects are taken into account, specifically at high and low frequencies and small and large amplitudes of flapping. The objective is to determine the thrust and efficiency of the flapping –foils under the influence of added effects of the free surface. Results show that the free-surface can significantly affect the foil performance by increasing the efficiency particularly at high Frequencies.
Show less
Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FA00004351, http://purl.flvc.org/fau/fd/FA00004351
Subject Headings
Aerodynamics -- Mathematical models, Fluid mechanics, Naval architecture, Ships -- Aerodynamics, Steering gear
Format
Document (PDF)
Studies of composite multihull ship structures using fluid structure interaction
Title
Studies of composite multihull ship structures using fluid structure interaction.
Creator
Ma, Siyuan, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Studies of composite multihull structure under wave loads, extreme loads, and blast loads have been conducted using finite element and computational fluid dynamics (CPF) tools. A comprehensive finite element tool for structural analysis of composite multi-hull structures is developed. Two-way fluid structure interaction (FSI) is implemented by coupling finite element analysis (FEA) and CFD. FEA models have been developed using sandwich construction having composite face sheets and a foam core...
Show moreStudies of composite multihull structure under wave loads, extreme loads, and blast loads have been conducted using finite element and computational fluid dynamics (CPF) tools. A comprehensive finite element tool for structural analysis of composite multi-hull structures is developed. Two-way fluid structure interaction (FSI) is implemented by coupling finite element analysis (FEA) and CFD. FEA models have been developed using sandwich construction having composite face sheets and a foam core. Fluid domain was modeled using the CFD code, CFX and a wave motion was simulated based on Sea State 5... In addition to hydrodynamic loads, the simulation of composite ship under extreme loads is performed. Stress analysis was performed and dynamic response of the hull was determined in time domain. In the final analysis, an underwater explosion model was developed to study the composite hull resistance to blast load.
Show less
Date Issued
2012
PURL
http://purl.flvc.org/FAU/3355625
Subject Headings
Computational fluid dynamics, Numerical analysis, Engineering mathematics, Naval architecture, Structural analysis (Engineering)
Format
Document (PDF)
Analysis of ship hull and plate vibrations caused by wave forces
Title
Analysis of ship hull and plate vibrations caused by wave forces.
Creator
Lakitosh, Fnu, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
In the present dissertation, the hydrodynamic and hydro-elastic characteristics of ship hull and plate vibrations are analyzed using theoretical and numerical methods. The wave forces are determined using a suite of methods which include the Froude-Krylov method for incident wave forces, Wagner's method and ABS rules for the slamming wave force, and numerical methods for nonlinear wave radiation forces. Finite difference methods are developed to determine the wave forced vibrations of ship...
Show moreIn the present dissertation, the hydrodynamic and hydro-elastic characteristics of ship hull and plate vibrations are analyzed using theoretical and numerical methods. The wave forces are determined using a suite of methods which include the Froude-Krylov method for incident wave forces, Wagner's method and ABS rules for the slamming wave force, and numerical methods for nonlinear wave radiation forces. Finite difference methods are developed to determine the wave forced vibrations of ship hull plates which are modeled using a range of plate theories including nonlinear plate theory with and without material damping and orthotropic plate theory for stiffened hull plates. For small amplitude deformation of thin plates, a semi-theoretical superposition method is used to determine the free and forced vibrations. The transient ship hull vibration due to whipping is also analyzed using the finite difference method. Results, in the form of deformations and stress distributions, are obtained for a range of scantling and wave parameters to identify key parameters to consider in ship structural design.
Show less
Date Issued
2012
PURL
http://purl.flvc.org/FAU/3342196
Subject Headings
Vibration (Marine engineering), Hulls (Naval architecture), Ships, Hydraulic impact, Ocean waves, Mathematical models, Fluid dynamics, Mathematical models
Format
Document (PDF)
Design and analysis of hybrid titanium-composite hull structures under extreme wave and slamming loads
Title
Design and analysis of hybrid titanium-composite hull structures under extreme wave and slamming loads.
Creator
Rahman, Md Hafizur, Mahfuz, Hassan, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
A finite element tool has been developed to design and investigate a multi-hull composite ship structure, and a hybrid hull of identical length and beam. Hybrid hull structure is assembled by Titanium alloy (Ti-6Al-4V) frame and sandwich composite panels. Wave loads and slamming loads acting on both hull structures have been calculated according to ABS rules at sea state 5 with a ship velocity of 40 knots. Comparisons of deformations and stresses between two sets of loadings demonstrate that...
Show moreA finite element tool has been developed to design and investigate a multi-hull composite ship structure, and a hybrid hull of identical length and beam. Hybrid hull structure is assembled by Titanium alloy (Ti-6Al-4V) frame and sandwich composite panels. Wave loads and slamming loads acting on both hull structures have been calculated according to ABS rules at sea state 5 with a ship velocity of 40 knots. Comparisons of deformations and stresses between two sets of loadings demonstrate that slamming loads have more detrimental effects on ship structure. Deformation under slamming is almost one order higher than that caused by wave loads. Also, Titanium frame in hybrid hull significantly reduces both deformation and stresses when compared to composite hull due to enhancement of in plane strength and stiffness of the hull. A 73m long hybrid hull has also been investigated under wave and slamming loads in time domain for dynamic analysis.
Show less
Date Issued
2013
PURL
http://purl.flvc.org/fau/fd/FA0004048
Subject Headings
Hulls (Naval architecture) -- Design and construction, Ships -- United States -- Design and construction, Structural dynamics, Water waves -- Mathematical models
Format
Document (PDF)