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Title: Analytical studies of concrete double-tee bridge system prestressed with FRP materials.
Creator: Qiao, Pizhong., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The finite element analyses of the concrete bridge system and single double-tee beams are carried out using both orthotropic and isotropic modeling including linear and nonlinear behavior. The orthotropic concrete double-tee bridge system is modeled to predict the deformational behavior of bridge deck under the AASHTO service loading conditions in the static regimes. The nonlinear analyses of reinforced and prestressed concrete rectangular beams are also carried out to verify the validity of...
Show moreThe finite element analyses of the concrete bridge system and single double-tee beams are carried out using both orthotropic and isotropic modeling including linear and nonlinear behavior. The orthotropic concrete double-tee bridge system is modeled to predict the deformational behavior of bridge deck under the AASHTO service loading conditions in the static regimes. The nonlinear analyses of reinforced and prestressed concrete rectangular beams are also carried out to verify the validity of modeling. Both the linear and nonlinear finite element analyses for single double-tee beams prestressed with FRP materials are carried out in this study. In this research, the MARC finite element software on the VAX frame is used as a tool to carry out the analyses.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14936
Subject Headings: Finite element method, Fiber reinforced plastic, Bridges, Concrete--Floors, Prestressed concrete beams
Format: Document (PDF)

Title: Debond test of steel plate bonded with concrete exposed to harsh environment.
Creator: Tharitimanont, Pattanaphol., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This study presents the experimental and theoretical studies on debond of steel bonded to concrete, which aids in understanding the mechanics of the repaired damaged prestressed concrete girders with externally bonded steel plates. The bond strength of bonded steel plate specimen is determined experimentally by the debond test. The initial crack is introduced in the specimens at three different locations, which include the steel/adhesive interface, adhesive through-thickness, and adhesive...
Show moreThis study presents the experimental and theoretical studies on debond of steel bonded to concrete, which aids in understanding the mechanics of the repaired damaged prestressed concrete girders with externally bonded steel plates. The bond strength of bonded steel plate specimen is determined experimentally by the debond test. The initial crack is introduced in the specimens at three different locations, which include the steel/adhesive interface, adhesive through-thickness, and adhesive/concrete interface. Certain debond test specimens are exposed to freeze/thaw and tidal cycles to evaluate the degradation in bond strength resulting from the environmental conditions. The fracture toughness for debonding would be evaluated and expressed as the critical strain energy release rate. A finite element analysis was performed to evaluate the compliance and stress distribution in the debond test specimens. Also, stress distribution of repaired AASHTO prestressed concrete bridge girders with metal sleeve splice was also determined at the interface of steel and concrete.
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Date Issued: 1999
PURL: http://purl.flvc.org/fcla/dt/15681
Subject Headings: Bridges, Concrete--Testing, Prestressed concrete construction, Finite element method, Concrete--Environmental testing
Format: Document (PDF)

Title: Finite element modeling of dislocation multiplication in microelectronic and optoelectronic devices/circuits.
Creator: Wang, Xueming., Florida Atlantic University, Tsai, Chi-Tay, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Two-dimensional and three-dimensional methodologies are developed to determine the dislocation multiplication in microelectronic and optoelectronic devices/circuits. A two-dimensional finite element code is developed to simulate the dislocation multiplication in microelectronic and optoelectronic devices/circuits. Example two-dimensional analyses are performed and analysis results are presented. The three-dimensional methodology is successfully implemented using ANSYS APDL Language within the...
Show moreTwo-dimensional and three-dimensional methodologies are developed to determine the dislocation multiplication in microelectronic and optoelectronic devices/circuits. A two-dimensional finite element code is developed to simulate the dislocation multiplication in microelectronic and optoelectronic devices/circuits. Example two-dimensional analyses are performed and analysis results are presented. The three-dimensional methodology is successfully implemented using ANSYS APDL Language within the ANSYS program. A three dimensional heterojunction bipolar transistor model is generated. CFD-thermal and structural analyses are performed to determine temperature fields and dislocation densities, which are calculated as functions of time, thickness of the thermal shunt, and heat generation rates.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12182
Subject Headings: Finite element method, Computational grids, ANSYS (Computer systems), Semiconductors--Materials--Analysis
Format: Document (PDF)

Title: The finite element method as a parametric tool in the design and analysis of a pressure vessel having a threaded closure.
Creator: Merkl, Garrett Andrew., Florida Atlantic University, Case, Robert O., Tsai, Chi-Tay, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The finite element method is a very powerful tool used to analyze a variety of problems in engineering. This thesis looks at the finite element method as a tool and several important modeling features of concern. A well known finite element software package, ANSYS, will be used to demonstrate a diverse number of its capabilities, and several procedures followed in solving a specific engineering problem. The subject matter involves a nonlinear contact analysis of a pressure vessel having a...
Show moreThe finite element method is a very powerful tool used to analyze a variety of problems in engineering. This thesis looks at the finite element method as a tool and several important modeling features of concern. A well known finite element software package, ANSYS, will be used to demonstrate a diverse number of its capabilities, and several procedures followed in solving a specific engineering problem. The subject matter involves a nonlinear contact analysis of a pressure vessel having a threaded closure. The choice of this application is prompted by an interest in better understanding how the finite element method is implemented in the design and analysis of different pressure vessel parameters. A parametric finite element analysis was performed. Load and stress distributions along the threaded region of the vessel were examined for parameters including number of threads, thread pitch, diameter ratio, closure plug length, and thread profile.
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Date Issued: 1996
PURL: http://purl.flvc.org/fcla/dt/15243
Subject Headings: Finite element method, Pressure vessels--Design and construction, Strains and stresses--Mathematical models
Format: Document (PDF)

$combined FEM-fracture mechanics analysis approach for I.C. packages$

Title: A combined FEM-fracture mechanics analysis approach for I.C. packages.
Creator: Renavikar, Ajit Anand., Florida Atlantic University, Stevens, Karl K., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A study of the stress distribution in and fracture behavior of the hermetic glass seal in a typical Integrated Circuit package is presented herein. Finite Element Analysis and Fracture Mechanics approaches were found effective for this investigation. A prescribed load or displacement applied at the tip of the lead protruding from the package causes high stresses at the lead-glass interface, which can lead to cracking and fracture of the seal. An approach for finding the value of the allowable...
Show moreA study of the stress distribution in and fracture behavior of the hermetic glass seal in a typical Integrated Circuit package is presented herein. Finite Element Analysis and Fracture Mechanics approaches were found effective for this investigation. A prescribed load or displacement applied at the tip of the lead protruding from the package causes high stresses at the lead-glass interface, which can lead to cracking and fracture of the seal. An approach for finding the value of the allowable load or displacement applicable at the lead tip is discussed. A correlation with a standard crack shape is presented for the 3-D model of the package. An extension of the problem revealing the effects of crack propagation on the stress intensity factor for the glass material is presented in later chapters. The J-integral method from Fracture Mechanics is found to be extremely useful for this investigation. A decline in the stress intensity factor with crack growth was observed from this study.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14511
Subject Headings: Integrated circuits--Fracture, Fracture mechanics, Finite element method, Electronics--Materials--Fatigue
Format: Document (PDF)

Title: Modal analysis of plates with uncertain properties: Theory and applications.
Creator: Wu, Jingshu., Florida Atlantic University, Stevens, Karl K., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This dissertation is concerned with modal analysis of plates with properties which vary over the structures. The uncertain geometric and material parameters are treated as random fields which are discretized over individual regions by using a local averaging technique. These discretized properties are then combined with a random perturbation procedure based upon traditional finite element methods. The result is a stochastic finite element method (SFEM) program for modal analysis of plates....
Show moreThis dissertation is concerned with modal analysis of plates with properties which vary over the structures. The uncertain geometric and material parameters are treated as random fields which are discretized over individual regions by using a local averaging technique. These discretized properties are then combined with a random perturbation procedure based upon traditional finite element methods. The result is a stochastic finite element method (SFEM) program for modal analysis of plates. This SFEM method is applied to two problems areas. The first application is to provide a new approach for modal analysis of printed circuit boards wherein the circuit board is modeled as an elastic plate with random spatial variation of its properties. The SFEM program is used to predict the effect of this variation on the natural frequencies and mode shapes of the board. Predicted results are compared with those obtained from modal testing of a circuit board. It is shown that variations between the measured and predicted modal parameters can be accounted for by small random variations in the board properties. This approach offers a simple, realistic, and cost-effective way for prediction of board modal properties. The second application is on vibration control of plates by application of surface viscoelastic damping treatments. Existing works generally treat the geometric and material properties of the damping layer as deterministic parameters, although uncertainties in the values of these parameters are commonplace. No work has been done regarding surface damping treatments with uncertain properties. In this thesis, the modal properties of plates with random spatial variation of the damping layer properties are investigated. The effects of this variation on the system natural frequencies, modal loss factors, and mode shapes are calculated by the SFEM program developed. Results are presented for a cantilever aluminum plate with complete PVC surface damping treatment with uncertain properties. In the SFEM modeling of both PC boards and plates with surface damping treatments, the effects on the system eigenvalues/eigenvectors of the correlation distance of the random property field, the correlation constant between the random fluctuations, and the magnitude of the random property variations, are investigated.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/12335
Subject Headings: Modal analysis, Stochastic processes, Finite element method, Plates (Engineering)--Testing
Format: Document (PDF)

Title: A three-dimensional finite element model for the biomechanical analysis of total ankle replacement.
Creator: Vo, Ha Van., Florida Atlantic University, Han, Chingping (Jim), College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The artificial ankle joint implant has been developed since 1970 after the relatively successful total hip and knee arthroplasty. The main goal of ankle replacement is to eliminate pain and preserve joint motion. Unfortunately, total ankle replacement (TAR) has not been effective as implant of other joints. Recently, published studies of early series showed that the newer second-generation ankle prosthesis have been improved with time. However, only one of the three current ankle designs is...
Show moreThe artificial ankle joint implant has been developed since 1970 after the relatively successful total hip and knee arthroplasty. The main goal of ankle replacement is to eliminate pain and preserve joint motion. Unfortunately, total ankle replacement (TAR) has not been effective as implant of other joints. Recently, published studies of early series showed that the newer second-generation ankle prosthesis have been improved with time. However, only one of the three current ankle designs is allowed by FDA to be used widely in the U.S. This study provides a new ankle design with an advanced approach in designs, biomechanical rationale, and implantation using finite element method (FEM). The new ankle prosthesis in designed to be optimal in terms of ultimate stress, implant parameter that correlating with minimal bone removal using finite element model created from CT scan. In addition, its implantation is less invasive and traumatic compared to the current TAR with longer expecting service life time. Case study showed that the thickness meniscus of the new ankle design obtained from FEM is well within the recommendation ranges by the expert in the ankle joint implantation field.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/12052
Subject Headings: Ankle--Effect of implants on, Artificial joints, Ankle--Mechanical properties, Finite element method
Format: Document (PDF)

Title: Stress intensity factors and weight functions for surface cracks using boundary/finite element alternating methods.
Creator: Mu, Ruijia., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In the present investigation, the boundary/finite element alternating methods are used to evaluate the stress intensity factors and weight functions for surface crack problems. For two dimensional problems, Westergaard stress functions are used to find the analytical solutions for an infinite plate with an embedded crack, subjected to crack face tractions, and the boundary element method for the numerical solution. The stress intensity factors and weight functions for an arbitrary plate with...
Show moreIn the present investigation, the boundary/finite element alternating methods are used to evaluate the stress intensity factors and weight functions for surface crack problems. For two dimensional problems, Westergaard stress functions are used to find the analytical solutions for an infinite plate with an embedded crack, subjected to crack face tractions, and the boundary element method for the numerical solution. The stress intensity factors and weight functions for an arbitrary plate with an edge crack subjected to mixed mode loads are obtained by the alternating technique. For three dimensional problems, an elliptical coordinate system and the gravity potential functions are used to derive the three dimensional analytical solutions for an infinite solid with an embedded crack. The analytical solutions are derived for the cases of shear tractions and normal tractions, separately, by assuming that the tractions are symmetric about both the major and minor axes. Superposition gives the general solutions. The analytical solutions and the finite element method, in conjunction with alternating technique, are used to evaluate the stress intensity factors for a solid with a semi-elliptical surface crack, subjected to arbitrary loads. A general approach to evaluate the weight functions for a two dimensional plate with a three dimensional semi-elliptical surface crack is formulated. Numerical examples are evaluated using the formulation developed in the present investigation. The results show good agreement with those from classical solutions. The convergence characteristics of the alternating methods are also discussed. Finally, the formulation is applied to welded plate T-joints with edge/semi-elliptical surface cracks, subjected to three point bending, to obtain stress intensity factors.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/12319
Subject Headings: Fracture mechanics, Finite element method--Data processing, Materials--Fatigue, Strains and stresses
Format: Document (PDF)

Title: Finite Element Modeling and Fatigue Analysis of Composite Turbine Blades under Random Ocean Current and Turbulence.
Creator: Canino, Marco M., Mahfuz, Hassan, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Several modifications have been implemented to numerical simulation codes based on blade element momentum theory (BEMT), for application to the design of ocean current turbine (OCT) blades. The modifications were applied in terms of section modulus and include adjustments due to core inclusion, buoyancy, and added mass. Hydrodynamic loads and mode shapes were calculated using the modified BEMT based analysis tools. A 3D model of the blade was developed using SolidWorks. The model was...
Show moreSeveral modifications have been implemented to numerical simulation codes based on blade element momentum theory (BEMT), for application to the design of ocean current turbine (OCT) blades. The modifications were applied in terms of section modulus and include adjustments due to core inclusion, buoyancy, and added mass. Hydrodynamic loads and mode shapes were calculated using the modified BEMT based analysis tools. A 3D model of the blade was developed using SolidWorks. The model was integrated with ANSYS and several loading scenarios, calculated from the modified simulation tools, were applied. A complete stress and failure analysis was then performed. Additionally, the rainflow counting method was used on ocean current velocity data to determine the loading histogram for fatigue analysis. A constant life diagram and cumulative fatigue damage model were used to predict the OCT blade life. Due to a critical area of fatigue failure being found in the blade adhesive joint, a statistical analysis was performed on experimental adhesive joint data.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004727, http://purl.flvc.org/fau/fd/FA00004727
Subject Headings: Composite materials -- Fatigue, Finite element method, Fluid dynamics, Marine turbines -- Mathematical models, Ocean wave power, Structural dynamics
Format: Document (PDF)

Title: Finite Element Modeling of Dislocation Multiplication in Silicon Carbide Crystals Grown by Physical Vapor Transport Method.
Creator: Chen, Qingde, Tsai, Chi-Tay, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Silicon carbide as a representative wide band-gap semiconductor has recently received wide attention due to its excellent physical, thermal and especially electrical properties. It becomes a promising material for electronic and optoelectronic device under high-temperature, high-power and high-frequency and intense radiation conditions. During the Silicon Carbide crystal grown by the physical vapor transport process, the temperature gradients induce thermal stresses which is a major cause of...
Show moreSilicon carbide as a representative wide band-gap semiconductor has recently received wide attention due to its excellent physical, thermal and especially electrical properties. It becomes a promising material for electronic and optoelectronic device under high-temperature, high-power and high-frequency and intense radiation conditions. During the Silicon Carbide crystal grown by the physical vapor transport process, the temperature gradients induce thermal stresses which is a major cause of the dislocations multiplication. Although large dimension crystal with low dislocation density is required for satisfying the fast development of electronic and optoelectronic device, high dislocation densities always appear in large dimension crystal. Therefore, reducing dislocation density is one of the primary tasks of process optimization. This dissertation aims at developing a transient finite element model based on the Alexander-Haasen model for computing the dislocation densities in a crystal during its growing process. Different key growth parameters such as temperature gradient, crystal size will be used to investigate their influence on dislocation multiplications. The acceptable and optimal crystal diameter and temperature gradient to produce the lowest dislocation density in SiC crystal can be obtained through a thorough numerical investigation using this developed finite element model. The results reveal that the dislocation density multiplication in SiC crystal are easily affected by the crystal diameter and the temperature gradient. Generally, during the iterative calculation for SiC growth, the dislocation density multiples very rapidly in the early growth phase and then turns to a relatively slow multiplication or no multiplication at all. The results also show that larger size and higher temperature gradient causes the dislocation density enters rapid multiplication phase sooner and the final dislocation density in the crystal is higher.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004489, http://purl.flvc.org/fau/fd/FA00004489
Subject Headings: Computational grids, Crystals -- Mathematical models, Differential equations -- Data processing, Dislocations in crystals, Engineering mathematics, Finite element method
Format: Document (PDF)

Title: Development of a graphical user interface for a Stewart platform.
Creator: Subramanian, Chenthilvel Muthukumaran., Florida Atlantic University, Masory, Oren, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A user friendly graphical interface was developed to control a Stewart platform which is a six degree-of-freedom in-parallel mechanism. The interface allows the user to define the platform motion relative to various coordinate systems: base, platform and joint. The velocity/position reference to the platform's controller can be provided by the following ways: preprogrammed data file, serial communication RS-232, 6 degrees of freedom joystick and soft teach pendant. The platform was designed...
Show moreA user friendly graphical interface was developed to control a Stewart platform which is a six degree-of-freedom in-parallel mechanism. The interface allows the user to define the platform motion relative to various coordinate systems: base, platform and joint. The velocity/position reference to the platform's controller can be provided by the following ways: preprogrammed data file, serial communication RS-232, 6 degrees of freedom joystick and soft teach pendant. The platform was designed to be used as "Space Emulator" and therefore a 6 degrees of freedom force/torque sensor was needed. Two different models of such sensors were designed and analyzed using finite element analysis techniques. Based on the results one particular model was selected, fabricated, instrumented with strain gages and calibrated in order to obtain its stiffness matrix. The effect of drifting of the sensor output due to self heating of the strain gages and the electronic components of the strain gage amplifiers was also studied.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14941
Subject Headings: Robots--Control systems, Robotics--Calibration, Manipulators (Mechanism), Finite element method, Graphical user interfaces (Computer systems)
Format: Document (PDF)

FAU Theses and Dissertations (29)	+ -
HBOI Faculty Contributions (1)	+ -
Honors Student Theses (1)	+ -

Finite element method (29)	+ -
Fracture mechanics (3)	+ -
Computational grids (2)	+ -
Fluid dynamics (2)	+ -
Piezoelectric transducers (2)	+ -

Prevention (2)	+ -
Stochastic processes (2)	+ -
ANSYS (Computer systems) (1)	+ -
Acoustic emission (1)	+ -
Aerodynamics (1)	+ -
Algorithms (1)	+ -
Ankle--Effect of implants on (1)	+ -
Ankle--Mechanical properties (1)	+ -
Artificial joints (1)	+ -
Bridges, Concrete--Floors (1)	+ -
Bridges, Concrete--Testing (1)	+ -
Cables (1)	+ -
Cables, Submarine--Mathematical models (1)	+ -
Cathodic protection (1)	+ -
Composite materials -- Fatigue (1)	+ -
Concrete beams--Vibration (1)	+ -
Concrete--Environmental testing (1)	+ -
Corrosion and anti-corrosives (1)	+ -
Crosstalk (1)	+ -
Crystals -- Mathematical models (1)	+ -
Differential equations -- Data processing (1)	+ -
Diffusion bonding (Metals) (1)	+ -
Dislocations in crystals (1)	+ -
Elastic analysis (Engineering) (1)	+ -
Electronics--Materials--Fatigue (1)	+ -

Electronic Thesis or Dissertation (29)	+ -
article (1)	+ -
thesis (1)	+ -

Florida Atlantic University (27)	+ -
College of Engineering and Computer Science (24)	+ -
Department of Ocean and Mechanical Engineering (22)	+ -
Tsai, Chi-Tay (6)	+ -
Case, Robert O. (3)	+ -

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