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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: 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: 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: Reinforcement of syntactic foam with SiC nanoparticles.
Creator: Das, Debdutta., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In this investigation, polymer precursor of syntactic foam has been reinforced with SiC nanoparticles to enhance mechanical and fracture properties. Derakane 8084 vinyl ester resin was first dispersed with 1.0 wt% of SiC particles using a sonic cavitation technique. In the next step, 30.0 wt% of microspheres (3M hollow glass borosilicate, S-series) were mechanically mixed with the nanophased vinyl ester resin, and cast into rectangular molds. A small amount of styrene was used as dilutant to...
Show moreIn this investigation, polymer precursor of syntactic foam has been reinforced with SiC nanoparticles to enhance mechanical and fracture properties. Derakane 8084 vinyl ester resin was first dispersed with 1.0 wt% of SiC particles using a sonic cavitation technique. In the next step, 30.0 wt% of microspheres (3M hollow glass borosilicate, S-series) were mechanically mixed with the nanophased vinyl ester resin, and cast into rectangular molds. A small amount of styrene was used as dilutant to facilitate mixing of microspheres. The size of microspheres and SiC nanoparticles were 20-30 um and 30-50 nm, respectively. Tension, compression, and flexure tests were conducted following ASTM standards and a consistent improvement in strength and modulus within 20-35% range was observed. Fracture toughness parameters such as KIC and GIC were also determined using ASTM E-399. An improvement of about 11-15% was observed. Samples were also subjected to various environmental conditions and degradation in material properties is reported.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/359923
Subject Headings: Composite materials, Design, Polyurethanes, Mechanical properties, Epoxy resins, Nanostructured materials
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: 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)

Title: Mechanical characterization of woven fabric composite materials.
Creator: Alif, Nidal M., Florida Atlantic University, Carlsson, Leif A., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The mechanical behavior of woven fabric composites is presented in this study through modeling of the elastic properties and experimental studies on the failure behavior and fracture analysis. A two-dimensional laminate theory based elastic model for the prediction of the elastic constants of satin weave fabric composites is developed. The predicted elastic constants are compared with results from other models and correlated with the experimental data. An experimental study is presented on...
Show moreThe mechanical behavior of woven fabric composites is presented in this study through modeling of the elastic properties and experimental studies on the failure behavior and fracture analysis. A two-dimensional laminate theory based elastic model for the prediction of the elastic constants of satin weave fabric composites is developed. The predicted elastic constants are compared with results from other models and correlated with the experimental data. An experimental study is presented on mechanical response in tension, compression and shear and on damage development in tension of two woven fabric composite systems viz. carbon/epoxy and glass/epoxy. Damage inspection of the carbon/epoxy composite under tension revealed that the initial failure was cracking of pure matrix regions followed by transverse bundle cracking. Fill/warp debonding and longitudinal splits of the fill bundles occurred close to ultimate failure of the composite. The glass/epoxy composite displayed damage in the form of fill/warp debonding and longitudinal splits, but no transverse yarn cracking. Interlaminar fracture behavior of a five-harness satin orthogonal woven fabric carbon/epoxy composite laminate loaded in mode I, mode II and mixed mode has been investigated. Special emphasis was put on microscopic details of crack growth, and their relation to the fracture resistance. For all fracture mode combinations it was found that crack growth occurred in a nonplanar region of topology determined by the weave pattern and relative positioning of the plies adjacent to the crack plane. The woven fabric structure constrains fiber bridging, but partial debonding of transversely oriented fiber bundles led to occasional crack branching, stick-slip behavior leading to variations in the mode I fracture resistance. Slow stable crack growth occurred in the mode I and mode II fracture specimens prior to unstable fracture and resulted in nonlinear load-displacement response.
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Date Issued: 1996
PURL: http://purl.flvc.org/fcla/dt/12481
Subject Headings: Composite materials--Mechanical properties, Textile fabrics--Mechanical properties, Elastic fabrics
Format: Document (PDF)

Title: Nanoparticle Reinforced Core Materials for Sandwich Construction: Investigation of Mechanical and Fracture Behavior.
Creator: Stewart, Justin Keith, Mahfuz, Hassan, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Sandwich composites provide excellent structural integrity for a variety of applications. In this study pristine and functionalized 30 nrn Silicon Carbide nanoparticles are infused into a low density polyurethane foam used for the inner core of the sandwich structure. The mechanical properties are characterized using compressive, tensile, and flexural tests. A plane-strain fracture test and a TSD (Tilted Sandwich Debond) test characterize the fracture properties of the foam and the coreskin...
Show moreSandwich composites provide excellent structural integrity for a variety of applications. In this study pristine and functionalized 30 nrn Silicon Carbide nanoparticles are infused into a low density polyurethane foam used for the inner core of the sandwich structure. The mechanical properties are characterized using compressive, tensile, and flexural tests. A plane-strain fracture test and a TSD (Tilted Sandwich Debond) test characterize the fracture properties of the foam and the coreskin interface. Thermal characterization is carried out using Dynamic Mechanical Analysis (DMA) and Thermo-Gravimetric Analysis (TGA). FTIR spectral analysis reveals changes in molecular bonding due to pristine and functionalized nanoparticle infusion. The fracture resistance of the foam is improved and the delamination strength of the sandwich construction with nanophased cores is dramatically improved. The TSD testing indicated that the G1c value rose from 0.14 kJ/m^2 in the neat foam to 0.56 kJ/m^2 with just 0.1 wt% of SiC nanoparticle inclusion reflecting an enhancement of almost 300%.
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Date Issued: 2008
PURL: http://purl.flvc.org/fau/fd/FA00012558
Subject Headings: Composite materials--Mechanical properties, Nanostructured materials--Testing, Fracture mechanics
Format: Document (PDF)

Composite materials (6)	+ -
Mechanical properties (6)	+ -
Fibrous composites (5)	+ -
Composite materials--Mechanical properties (3)	+ -
Graphite fibers (3)	+ -

Deterioration (2)	+ -
Nanostructured materials (2)	+ -
Polymers (2)	+ -
Structural analysis (2)	+ -
Carbon composites. (1)	+ -
Carbon compounds (1)	+ -
Carbon nanotubes. (1)	+ -
Composite materials -- Mechanical properties (1)	+ -
Composite materials -- Testing (1)	+ -
Composite materials--Mechanical properties. (1)	+ -
Design (1)	+ -
Elastic fabrics (1)	+ -
Epoxy resins (1)	+ -
FIbrous composites (1)	+ -
Fibrous composites -- Mechanical properties (1)	+ -
Fibrous composites--Testing (1)	+ -
Fracture mechanics (1)	+ -
Nanostructured materials--Testing (1)	+ -
Nanostructured materials. (1)	+ -
Polymeric composites (1)	+ -
Polymeric composites -- Mechanical properties (1)	+ -
Polymeric composites--Testing (1)	+ -
Polymeric composites. (1)	+ -
Polymers--Deterioration (1)	+ -
Polyurethanes (1)	+ -

College of Engineering and Computer Science (11)	+ -
Department of Ocean and Mechanical Engineering (11)	+ -
Florida Atlantic University (5)	+ -
Carlsson, Leif A. (3)	+ -
Mahfuz, Hassan (2)	+ -

Alif, Nidal M. (1)	+ -
Das, Debdutta. (1)	+ -
Farooq, Muhammad Umar. (1)	+ -
Figliolini, Alexander M. (1)	+ -
Hasnine, Md. (1)	+ -
Powell, Felicia M. (1)	+ -
Ramirez, Felipe A. (1)	+ -
Sabet, Seyed Morteza (1)	+ -
Stewart, Justin Keith (1)	+ -
Totten, Kyle (1)	+ -
Vinci, Chris J. (1)	+ -

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