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Title: Development of Flexible Puncture Resistant Materials System Using Silica Nanoparticles.
Creator: Clements, Floria Eve, Mahfuz, Hassan, Florida Atlantic University
Abstract/Description: Nanoscale silica particles are functionalized and ultrasonically dispersed into a mixture of polyethylene glycol and ethanol, and then reinforced with Kevlar. The stab or puncture resistance of the flexible nanophased materials system supersedes recent advances made in this area. Through SEM scans, thermal and chemical analysis, it is evident that the functionalized nanoparticles offer multiple facets of resistance to penetration of a sharp impactor. The improvement in protection is traced to...
Show moreNanoscale silica particles are functionalized and ultrasonically dispersed into a mixture of polyethylene glycol and ethanol, and then reinforced with Kevlar. The stab or puncture resistance of the flexible nanophased materials system supersedes recent advances made in this area. Through SEM scans, thermal and chemical analysis, it is evident that the functionalized nanoparticles offer multiple facets of resistance to penetration of a sharp impactor. The improvement in protection is traced to the formation of siloxane bonds during functionalization. The framework for a theoretical model is established to estimate penetration depth under low velocity impact of a sharp object through the flexible composite. For comparison ofthese novel fabric composites, a method is also introduced to evaluate penetration resistance quantitatively. The method is capable of showing subtle changes that would otherwise be missed.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012513
Subject Headings: Nanostructured materials, Reinforced plastics, Fibrous composites, Nanotechnology
Format: Document (PDF)

Title: The effects of POSS surface treatment on the interlaminar property of marine composites.
Creator: Powell, Felicia M., Granata, Richard D., Hosur, Mahesh, Mahfuz, Hassan, Graduate College
Date Issued: 2011-04-08
PURL: http://purl.flvc.org/fcla/dt/3164682
Subject Headings: Composite materials --Delamination, Fibrous composites, Polymers --Effect of radiation on
Format: Document (PDF)

Title: Carbon fiber/vinylester composites in the marine environment: EIS as a means of determining an effective composite interface.
Creator: Vinci, Chris J., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In this research, the degradation of carbon fiber/vinylester composites in marine environments was experimentally investigated. Additionally, two types of carbon fiber surface treatments, namely Polyhedral Oligomeric Silsesquioxane (POSS) and the industrial surface treatment F0E, were evaluated to determine their effectiveness in creating a fiber/matrix (F/M) interface for use in the marine environment. Electrochemical Impedance Spectroscopy (EIS) was explored as a new application of an...
Show moreIn this research, the degradation of carbon fiber/vinylester composites in marine environments was experimentally investigated. Additionally, two types of carbon fiber surface treatments, namely Polyhedral Oligomeric Silsesquioxane (POSS) and the industrial surface treatment F0E, were evaluated to determine their effectiveness in creating a fiber/matrix (F/M) interface for use in the marine environment. Electrochemical Impedance Spectroscopy (EIS) was explored as a new application of an existing technique for use in measuring the amount of water at the F/M interface in carbon fiber/vinylester composites. EIS spectra were used to determine equivalent electric circuit models that allow for the prediction of water at the interface. The location of water within the composite was determined through Positron Annihilation Lifetime Spectroscopy (PALS). Interlaminar shear strength and transverse tensile tests were carried out for dry conditions and after hygrothermal exposure of the composites to study the influence of the integrity of the F/M interface on the macroscopic response of the composite.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/1930500
Subject Headings: Composite materials, Mechanical properties, Graphite fibers, Fibrous composites, Structural analysis
Format: Document (PDF)

Title: Degradation of mechanical properties of vinylester and carbon fiber/vinylester composites due to environmental exposure.
Creator: Figliolini, Alexander M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: An experimental investigation was undertaken to determine the effects of marine environmental exposure on the mechanical properties of vinylester resins (VE510A and VE8084) and carbon fiber/VE510A vinylester composites. The effect of carbon fiber sizing on the composite strengths was also examined. Neat resins were exposed to marine environments until moisture content reached a point of saturation after which they were tested in tension, compression and shear. Compared to the baseline dry...
Show moreAn experimental investigation was undertaken to determine the effects of marine environmental exposure on the mechanical properties of vinylester resins (VE510A and VE8084) and carbon fiber/VE510A vinylester composites. The effect of carbon fiber sizing on the composite strengths was also examined. Neat resins were exposed to marine environments until moisture content reached a point of saturation after which they were tested in tension, compression and shear. Compared to the baseline dry specimens, specimens subjected to moisture showed overall increased ductility and a reduction in strength. Dry and moisture saturated composite specimens were tested in tension and compression in different orientations. Longitudinal specimens were tested in in-plane shear and interlaminar shear. Composites with F-sized carbon fibers displayed overall higher strength than those with G-sized fibers at both dry and moisture saturated conditions. An analysis of moisture absorption of the composites was performed which vii shows that the moisture up-take is dominated by the fiber/matrix region which absorbs up to 90% of the moisture. The composites experienced reduced strength after moisture absorption. The results revealed that the fiber sizing has stronger effect on the fiber/matrix interface dominated strengths than moisture up-take.
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Date Issued: 2011
PURL: http://purl.flvc.org/FAU/3332182
Subject Headings: Composite materials, Mechanical properties, Polymers, Deterioration, FIbrous composites, Graphite fibers
Format: Document (PDF)

Title: Degradation of the composite fiber/matrix interface in marine environment.
Creator: Farooq, Muhammad Umar., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Durability of the composite materials in marine environments has been investigated experimentally and with analytical and numerical methods. The main focus of this study is on the integrity of the fiber/matrix interface under seawater exposure. A single-fiber compression test specimen called the Outwater-Murphy (OM) test has been analyzed using mechanics of materials principles and linear elastic fracture mechanics. Sizing of the OM specimen was conducted so that debonding of the fiber from...
Show moreDurability of the composite materials in marine environments has been investigated experimentally and with analytical and numerical methods. The main focus of this study is on the integrity of the fiber/matrix interface under seawater exposure. A single-fiber compression test specimen called the Outwater-Murphy (OM) test has been analyzed using mechanics of materials principles and linear elastic fracture mechanics. Sizing of the OM specimen was conducted so that debonding of the fiber from the interface should be achieved prior to yielding of the matrix and global instability failure. Stress analysis of the OM specimen has been conducted from theory of elasticity and finite element analysis. A superelement technique was developed for detailed analysis of the stress state at the fiber/matrix interface. The interface stress state at the debond site in the OM specimen, i.e. at the hole edge, was identified as biaxial tension at the fiber/matrix interface. Characterization of cure and post-cure of 8084 and 510A vinlyester resins has been performed using cure shrinkage tests based on dynamic mechanical analysis and coated beam experiments. In addition, moisture absorption, swelling and the influence of moisture on the mechanical properties of the resins were determined. Testing of OM specimens consisting of a single carbon or glass fiber embedded in vinylester resin at dry conditions and after seawater exposure revealed that the debond toughness was substantially reduced after exposure of the OM specimen to seawater. C(F) did not debond. Macroscopic carbon/vinylester woven composites where the fibers were sized with F sizing were tested in shear at dry conditions and after four weeks of seawater exposure. The shear strength was very little affected after the short immersion time.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/228774
Subject Headings: Fibrous composites, Graphite fibers, Composite materials, Mechanical properties, Polymers, Deterioration
Format: Document (PDF)

Title: Mechanical properties of fiber-reinforced polymer (FRP) composites for concrete bridge deck reinforcement.
Creator: Manav, Mukbil Ozan., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description: Durability of concrete bridge decks reinforced with conventional structural steel is a major concern in aggressive environments. To address this problem, there have been efforts, in recent years, to develop and evaluate alternatives to conventional steel. One alternative is fiber reinforced polymer (FRP) composite reinforcement. FRP composites have been used successfully in many industrial applications. This thesis investigates short-term mechanical properties of FRP rebars as reinforcement...
Show moreDurability of concrete bridge decks reinforced with conventional structural steel is a major concern in aggressive environments. To address this problem, there have been efforts, in recent years, to develop and evaluate alternatives to conventional steel. One alternative is fiber reinforced polymer (FRP) composite reinforcement. FRP composites have been used successfully in many industrial applications. This thesis investigates short-term mechanical properties of FRP rebars as reinforcement for concrete bridge decks and discusses results of extensive laboratory tests. Four test methods (tension, flexure, shear and bond) are developed and test protocols are proposed for adoption by AASHTO.
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Date Issued: 2002
PURL: http://purl.flvc.org/fcla/dt/12988
Subject Headings: Fibrous composites--Mechanical properties, Polymeric composites, Reinforced concrete, Fiber
Format: Document (PDF)

Title: Determination of the tensile strength of the fiber/matrix interface for glass/epoxy & carbon/vinylester.
Creator: Totten, Kyle, Carlsson, Leif A., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The tensile strength of the fiber/matrix interface was determined through the development of an innovativetest procedure.Aminiature tensile coupon with a through-thickness oriented, embedded single fiberwas designed. Tensile testing was conducted ina scanning electron microscope (SEM)while the failure process could be observed.Finite element stress analysis was conducted to determine the state of stressat the fiber/matrix interface in the tensile loaded specimen, and the strength of the...
Show moreThe tensile strength of the fiber/matrix interface was determined through the development of an innovativetest procedure.Aminiature tensile coupon with a through-thickness oriented, embedded single fiberwas designed. Tensile testing was conducted ina scanning electron microscope (SEM)while the failure process could be observed.Finite element stress analysis was conducted to determine the state of stressat the fiber/matrix interface in the tensile loaded specimen, and the strength of the interface.Test specimensconsistingof dry E-glass/epoxy and dry and seawater saturatedcarbon/vinylester510Awere preparedand tested.The load at the onset of debondingwascombined withthe radial stressdistributionnear thefree surface of the specimento reducethe interfacial tensile strength. For glass/epoxy, was 36.7±8.8MPa.For the dryand seawater saturated carbon/vinylester specimensthetensilestrengthsof the interface were 23.0±6.6 and 25.2±4.1MPa, respectively.The difference is not significant.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004415, http://purl.flvc.org/fau/fd/FA00004415
Subject Headings: Composite materials -- Mechanical properties, Composite materials -- Testing, Fibrous composites -- Mechanical properties, Polymeric composites -- Mechanical properties, Viscoelasticity
Format: Document (PDF)

Title: Effects of Carbon Nanotube (CNT) Dispersion and Interface Condition on Thermo-Mechanical Behavior of CNT-Reinforced Vinyl Ester.
Creator: Sabet, Seyed Morteza, Mahfuz, Hassan, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In fabrication of nanoparticle-reinforced polymers, two critical factors need to be taken into account to control properties of the final product; nanoparticle dispersion/distribution in the matrix; and interfacial interactions between nanoparticles and their surrounding matrix. The focus of this thesis was to examine the role of these two factors through experimental methodologies and molecular-level simulations. Carbon nanotubes (CNTs) and vinyl ester (VE) resin were used as nanoparticles...
Show moreIn fabrication of nanoparticle-reinforced polymers, two critical factors need to be taken into account to control properties of the final product; nanoparticle dispersion/distribution in the matrix; and interfacial interactions between nanoparticles and their surrounding matrix. The focus of this thesis was to examine the role of these two factors through experimental methodologies and molecular-level simulations. Carbon nanotubes (CNTs) and vinyl ester (VE) resin were used as nanoparticles and matrix, respectively. In a parametric study, a series of CNT/VE nanocomposites with different CNT dispersion conditions were fabricated using the ultrasonication mixing method. Thermomechanical properties of nanocomposites and quality of CNT dispersion were evaluated. By correlation between nanocomposite behavior and CNT dispersion, a thermomechanical model was suggested; at a certain threshold level of sonication energy, CNT dispersion would be optimal and result in maximum enhancement in properties. This threshold energy level is also related to particle concentration. Sonication above this threshold level, leads to destruction of nanotubes and renders a negative effect on the properties of nanocomposites. In an attempt to examine the interface condition, a novel process was developed to modify CNT surface with polyhedral oligomeric silsesquioxane (POSS). In this process, a chemical reaction was allowed to occur between CNTs and POSS in the presence of an effective catalyst. The functionalized CNTs were characterized using TEM, SEM-EDS, AFM, TGA, FTIR and Raman spectroscopy techniques. Formation of amide bonds between POSS and nanotubes was established and verified. Surface modification of CNTs with POSS resulted in significant improvement in nanotube dispersion. In-depth SEM analysis revealed formation of a 3D network of well-dispersed CNTs with POSS connections to the polymer. In parallel, molecular dynamics simulation of CNT-POSS/VE system showed an effective load transfer from polymer chains to the CNT due to POSS linkages at the interface. The rigid and flexible network of CNTs is found to be responsible for enhancement in elastic modulus, strength, fracture toughness and glass transition temperature (Tg) of the final nanocomposites.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004628, http://purl.flvc.org/fau/fd/FA00004628
Subject Headings: Carbon nanotubes., Carbon composites., Polymeric composites., Fibrous composites, Nanostructured materials., Composite materials--Mechanical properties.
Format: Document (PDF)

Title: Durability of carbon fiber/vinylester composites subjected to marine environments and electrochemical interactions.
Creator: Hasnine, Md., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Degradation of the Carbon Fiber/Vinylester (CF/VE) polymer matrix composites due to different electrochemical interactions when exposed to seawater or at high temperature had been experimentally investigated. Water uptake behavior of composite specimen was examined based on weight gain measurement. Three point bending test was performed to quantify the mechanical degradation of composite immersed in seawater with different environmental and electrochemical interactions. Finally,...
Show moreDegradation of the Carbon Fiber/Vinylester (CF/VE) polymer matrix composites due to different electrochemical interactions when exposed to seawater or at high temperature had been experimentally investigated. Water uptake behavior of composite specimen was examined based on weight gain measurement. Three point bending test was performed to quantify the mechanical degradation of composite immersed in seawater with different environmental and electrochemical interactions. Finally, Electrochemical Impedance Spectroscopy (EIS) was used to better understanding of the degradation process in CF/VE composite produced by interactions between electrochemical and different environmental conditions. A detailed equivalent circuit analysis by using EIS spectra is also presented in an attempt to elucidate the degradation phenomenon in composites.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/2683124
Subject Headings: Composite materials, Mechanical properties, Fibrous composites, Structural analysis, Polymeric composites, Spectrum analysis
Format: Document (PDF)

Title: Evaluation of Water Degradation ofPolymer Matrix Composites by Micromechanical and Macromechanical Tests.
Creator: Ramirez, Felipe A., Carlsson, Leif A., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Degradation of the critical components of polymer matrix composites in marine environments had been experimentally investigated. Water absorption behavior of neat resin and composite specimens was examined. The tensile strength of fibers was monitored using the single filament test. The mechanical properties of the resins were monitored by tensile, flexure, and dynamic-mechanical tests. In addition, matrix shrinkage during cure and matrix swelling after immersion in water were monitored. The...
Show moreDegradation of the critical components of polymer matrix composites in marine environments had been experimentally investigated. Water absorption behavior of neat resin and composite specimens was examined. The tensile strength of fibers was monitored using the single filament test. The mechanical properties of the resins were monitored by tensile, flexure, and dynamic-mechanical tests. In addition, matrix shrinkage during cure and matrix swelling after immersion in water were monitored. The integrity of the fiber/matrix (F/M) interface of the composite systems was studied using the single fiber fragmentation test (SFFT). Macroscopic composites were examined using transverse tensile and transverse flexure tests to study the influence of the integrity of the matrix and F/M interface on the macroscopic response. In addition, for characterization of F/M debonding in the SFFT, a fracture mechanics model and modified test procedure were developed.
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Date Issued: 2008
PURL: http://purl.flvc.org/fau/fd/FA00012543
Subject Headings: Composite materials--Mechanical properties, Polymeric composites--Testing, Fibrous composites--Testing, Polymers--Deterioration
Format: Document (PDF)

$Fatigue and fracture of foam cores used in sandwich composites$

Title: Fatigue and fracture of foam cores used in sandwich composites.
Creator: Saenz, Elio., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This study focused on the fracture and fatigue crack growth behavior in polyvinylchloride (PVC) and polyethersulfone (PES) foams. A new sandwich double cantilever beam (DCB) test specimen was implemented. Elastic foundation and finite element analysis and experimental testing confirmed that the DCB specimen is appropriate for static and cyclic crack propagation testing of soft polymer foams. A comprehensive experimental mechanical analysis was conducted on PVC foams of densities ranging from...
Show moreThis study focused on the fracture and fatigue crack growth behavior in polyvinylchloride (PVC) and polyethersulfone (PES) foams. A new sandwich double cantilever beam (DCB) test specimen was implemented. Elastic foundation and finite element analysis and experimental testing confirmed that the DCB specimen is appropriate for static and cyclic crack propagation testing of soft polymer foams. A comprehensive experimental mechanical analysis was conducted on PVC foams of densities ranging from 45 to 100 kg/m3 and PES foams of densities ranging from 60 to 130 kg/m3. An in-situ scanning electron microscope study on miniature foam fracture specimens showed that crack propagation in the PVC foam was inter-cellular and in the PES foam, failure occurred predominately by extensional failure of vertical cell edges. Sandwich DCB specimens were loaded cyclically as well. For the PVC foams, the crack growth rates were substantially influenced by the density. For the PES foams, there was no clear indication about the influence of foam density on the crack growth rate.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3352829
Subject Headings: Sandwich construction, Composite materials, Fibrous composites, Strains and stresses, Management, Laminated materials, Plastics, Fatigue
Format: Document (PDF)

Title: A study of the effects of nanoparticle modification on the thermal, mechanical and hygrothermal performance of carbon/vinyl ester compounds.
Creator: Powell, Felicia M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Enhancement of mechanical, thermal and hygrothermal properties of carbon fiber/vinyl ester (CFVE) composites through nanoparticle reinforcement has been investigated. CFVE composites are becoming more and more attractive for marine applications due to two reasons : high specific strength and modulus of carbon fiber and low vulnerability of vinyl ester resin to sea water. However, the problem with this composite system is that the fiber matrix (F/M) interface is inherently weak. This leads to...
Show moreEnhancement of mechanical, thermal and hygrothermal properties of carbon fiber/vinyl ester (CFVE) composites through nanoparticle reinforcement has been investigated. CFVE composites are becoming more and more attractive for marine applications due to two reasons : high specific strength and modulus of carbon fiber and low vulnerability of vinyl ester resin to sea water. However, the problem with this composite system is that the fiber matrix (F/M) interface is inherently weak. This leads to poor mechanical properties and fast ingress of water at the interface further deteriorating the properties. This investigation attempts to address these deficiencies by inclusion of nanoparticles in CFVE composites. Three routes of nanoparticle reinforcement have been considered : nanoparticle coating of the carbon fiber, dispersion of nanoparticles in the vinyl ester matrix, and nanoparticle modification of both the fiber and the matrix. Flexural, short beam shear and tensile testing was conducted after exposure to dry and wet environments. Differential scanning calorimetry and dynamic mechanical analysis were conducted as well. Mechanical and thermal tests show that single inclusion of nanoparticles on the fiber or in the matrix increases carbon/vinyl ester composite properties by 11-35%. However, when both fiber and matrix were modified with nanoparticles, there was a loss of properties.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3352286
Subject Headings: Composite materials, Mechanical properties, Nanostructured materials, Testing, Carbon compounds, Testing, Fibrous composites, Testing, Surface chemistry
Format: Document (PDF)

Title: Strength and toughness of HDPE fiber reinforced aggregate concrete as a sustainable construction material.
Creator: Numa, Roody., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description: An experimental study was conducted on the strength and toughness characteristics of concrete made from recycled aggregate, cement and fly ash reinforced with reclaimed high density polyethylene plastic (HDPE) fibers. The objectives of the investigation were: (1) to evaluate the performance of a sustainable concrete containing up to 90% recycled materials; (2) to determine the variation of strength and toughness with a Fiber Factor incorporating length, width and amount of HDPE fibers; (3) to...
Show moreAn experimental study was conducted on the strength and toughness characteristics of concrete made from recycled aggregate, cement and fly ash reinforced with reclaimed high density polyethylene plastic (HDPE) fibers. The objectives of the investigation were: (1) to evaluate the performance of a sustainable concrete containing up to 90% recycled materials; (2) to determine the variation of strength and toughness with a Fiber Factor incorporating length, width and amount of HDPE fibers; (3) to identify the best performing mix design based on tensile strength and toughness and (4) to provide some guidelines for the use of this sustainable composite in Civil Engineering construction. The results showed that the HDPE fiber reinforcements did not improve the compressive strength of the mixture. However, HDPE fibers improved the ductility and toughness which may be beneficial for structural and pavement applications.
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Date Issued: 2011
PURL: http://purl.flvc.org/FAU/3172430
Subject Headings: Fibrous composites, Cement composites, Reinforced concrete, Fiber, Conposite-reinforced concrete
Format: Document (PDF)

Title: Behavior of repaired concrete structures with advanced composites in cold environment.
Creator: Thayer, Chad C., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This report presents the experimental and theoretical studies on the feasibility of using CFRP laminates for strengthening damaged reinforced concrete beams in cold environment. Experimental work includes investigation on fatigue strength, ultimate capacity and failure modes of repaired reinforced concrete beams in cold environment and room temperature. The repaired concrete beams subjected to fatigue in cold environment exhibit fewer number of cracks than those observed in beams at room...
Show moreThis report presents the experimental and theoretical studies on the feasibility of using CFRP laminates for strengthening damaged reinforced concrete beams in cold environment. Experimental work includes investigation on fatigue strength, ultimate capacity and failure modes of repaired reinforced concrete beams in cold environment and room temperature. The repaired concrete beams subjected to fatigue in cold environment exhibit fewer number of cracks than those observed in beams at room temperature. The crack propagation and resulting damage were faster in beams tested in room temperature than those at cold temperatures. The study also includes investigation of thermal response of repaired plain concrete beams with CFRP laminates subjected to thermal cycles. Analytical studies on the distributed shear forces and peeling forces of repaired reinforced concrete beams were carried out to analyze the interaction between the laminate and the concrete interface. The temperature distribution and strains developed by the temperature differential are determined in the repaired plain concrete beams subjected to thermal cycles and the analytical results compared with the measured values.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15517
Subject Headings: Reinforced concrete--Cracking, Fiber reinforced plastics, Composite materials--Effect of environment on, Fibrous composites--Fatigue
Format: Document (PDF)

Title: Effects of POSS Fiber Sizing on the Mechanical and Thermal Properties of CarbonNinyl Ester Composites.
Creator: Powell, Felicia M., Mahfuz, Hassan, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The degradation of polymer composites in moist environments is a limiting factor in the advancement of composite technology. The key to mitigate this degradation is to maintain the integrity of the fiber/matrix (F/M) interface. In this study, the F/M interface of carbon/vinyl ester composites has been modified by treating the carbon fiber with polyhedral oligomeric silsesquioxane (POSS). Two POSS systems, namely octaisobutyl and trisilanolphenyl, have been investigated. A set of chemical and...
Show moreThe degradation of polymer composites in moist environments is a limiting factor in the advancement of composite technology. The key to mitigate this degradation is to maintain the integrity of the fiber/matrix (F/M) interface. In this study, the F/M interface of carbon/vinyl ester composites has been modified by treating the carbon fiber with polyhedral oligomeric silsesquioxane (POSS). Two POSS systems, namely octaisobutyl and trisilanolphenyl, have been investigated. A set of chemical and mechanical procedures has been developed to coat carbon fibers with POSS, and fabricate layered composites using vinyl ester resin. lnterlaminar shear, transverse tension, and low velocity impact tests on composites have indicated around 10-38% improvement in mechanical properties with respect to control samples. Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) tests have also shown significant improvement in glass transition temperature (T9). Hygrothermal tests, under various environments, have demonstrated that POSS reduces water absorption by 20-30%.
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Date Issued: 2009
PURL: http://purl.flvc.org/fau/fd/FA00012540
Subject Headings: Surface chemistry, Composite materials--Biodegradation, Carbon compounds--Testing, Thermodynamics, Fibrous compounds--Testing
Format: Document (PDF)

Title: Experimental Evaluation of the Structural Integrity of the Repairs for Corrosion-Damaged Marine Piles.
Creator: Bolivar, Juan Carlos, Reddy, Dronnadula V., Florida Atlantic University
Abstract/Description: Corrosion damage is the mam cause of deterioration for reinforced concrete marine structures. Given the current economic downturn, it has become increasingly important to repair existing structures with techniques that prolong their life-cycle. The process to identify suitable repairs is affected by the lack of a consistent methodology to predict the outcome of the repairs. This investigation intends to compare the performance of seven different repairs, in terms of corrosion resistance,...
Show moreCorrosion damage is the mam cause of deterioration for reinforced concrete marine structures. Given the current economic downturn, it has become increasingly important to repair existing structures with techniques that prolong their life-cycle. The process to identify suitable repairs is affected by the lack of a consistent methodology to predict the outcome of the repairs. This investigation intends to compare the performance of seven different repairs, in terms of corrosion resistance, structural integrity, and cost-effectiveness. Following initial exposure to corrosion, the specimens were repaired using the proposed techniques. They were then tested for durability under simulated tidal conditions with periodic corrosion monitoring. The structural integrity was evaluated by crack scoring and ultimate load testing, and a comprehensive evaluation matrix was prepared, to determine which repairs were most adequate for corrosion damage. The results of this investigation substantiate that the repairs including carbon wrapping, HDPE jacketing, and MMFX steel, outperformed the rest of the repairs.
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Date Issued: 2008
PURL: http://purl.flvc.org/fau/fd/FA00012506
Subject Headings: Reinforced concrete--Corrosion, Underwater concrete construction--Maintenance and repair, Materials--Deterioration--Prevention, Fibrous composites--Evaluation
Format: Document (PDF)

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Deterioration (2)	+ -

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Polymeric composites (2)	+ -
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Reinforced concrete, Fiber (2)	+ -
Structural analysis (2)	+ -
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