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Electrochemical Impedance Spectroscopy To Monitor Degradation Of Carbon Fiber Reinforced Polymer Composites Subjected To Simulated Ocean Environment
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Book Synopsis Electrochemical Impedance Spectroscopy to Monitor Degradation of Carbon Fiber Reinforced Polymer Composites Subjected to Simulated Ocean Environment by : Mohammad M. Ahmed
Download or read book Electrochemical Impedance Spectroscopy to Monitor Degradation of Carbon Fiber Reinforced Polymer Composites Subjected to Simulated Ocean Environment written by Mohammad M. Ahmed and published by . This book was released on 1993 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effect of Carbon Fiber Type on the Electrochemical Degradation of Carbon Fiber Polymer Composites, Tri-Service Committee on Corrosion Proceedings by :
Download or read book The Effect of Carbon Fiber Type on the Electrochemical Degradation of Carbon Fiber Polymer Composites, Tri-Service Committee on Corrosion Proceedings written by and published by . This book was released on 1994 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The galvanic interaction between metals and carbon fiber/polymer matrix composite degrades not only the metals but the composite itself. The objective of this study was to investigate if the fiber type influenced either the mechanism or form of damage. Two different composites were examined. Both have same epoxy matrix, 3501-6 epoxy, but contain different carbon fibers, either AS4 or IM6. The surfaces of the composite materials were exposed to 0.5 N NaCl solution to simulate sea water at open circuit condition or cathodic potentials to simulate galvanic coupling of metals. Electrochemical impedance spectroscopy (EIS) was employed to monitor changes in the behavior of the composites. Modeling of experimental data indicated that the parameter, Rp, representing the polymer resistance decreased with increasing time of exposure for both open circuit conditions and applied cathodic potentials. The value of Rp also decreased with increasingly cathodic applied potentials. This suggested that a damage process for the polymer involving increased access of solution to the carbon fibers. SEM examination showed that cracks and polymer separations on the exposed but not on the unexposed surfaces. The fiber type did not appear to influence the damage mechanism in this study.
Book Synopsis Durability of Carbon Fiber/vinylester Composites Subjected to Marine Environments and Electrochemical Interactions by : Md Hasnine
Download or read book Durability of Carbon Fiber/vinylester Composites Subjected to Marine Environments and Electrochemical Interactions written by Md Hasnine and published by . This book was released on 2010 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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, 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.
Book Synopsis Masters Theses in the Pure and Applied Sciences by : Sade H Shafer
Download or read book Masters Theses in the Pure and Applied Sciences written by Sade H Shafer and published by Springer Science & Business Media. This book was released on 1995 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cited in Sheehy, Chen, and Hurt . Volume 38 (thesis year 1993) reports a total of 13,787 thesis titles from 22 Canadian and 164 US universities. As in previous volumes, thesis titles are arranged by discipline and by university within each discipline. Any accredited university or college with a grad
Book Synopsis Carbon Fiber/vinylester Composites in the Marine Environment by : Chris J. Vinci
Download or read book Carbon Fiber/vinylester Composites in the Marine Environment written by Chris J. Vinci and published by . This book was released on 2010 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 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.
Book Synopsis Masters Abstracts International by :
Download or read book Masters Abstracts International written by and published by . This book was released on 1994 with total page 1192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Master's Theses Directories written by and published by . This book was released on 1994 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Education, arts and social sciences, natural and technical sciences in the United States and Canada".
Book Synopsis The Simulation and Detection of Electrochemical Damage in BMI/Graphite Fiber Composites Using Electrochemical Impedance Spectroscopy by : FD. Wall
Download or read book The Simulation and Detection of Electrochemical Damage in BMI/Graphite Fiber Composites Using Electrochemical Impedance Spectroscopy written by FD. Wall and published by . This book was released on 1993 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electrochemical impedance spectroscopy (EIS) was used to monitor changes in the integrity of a bismalimide (BMI)/graphite fiber composite subjected to electrochemical and chemical stresses. Experiments included cathodic and anodic potentiostatic polarizations, exposure to caustic solutions, and galvanic coupling with various metals: aluminum, steel, copper, and titanium. EIS was found to provide a rapid and sensitive assessment of changes in the composite. EIS spectra of composite samples cathodically polarized greater than 200 mV from the composite open circuit (OC) indicated a transition from planar to porous electrode behavior. This response was attributed to the breakdown of the fiber/matrix interface possibly caused by hydroxyl ions produced at the fiber surfaces. Cathodic polarization below 200 mV versus OC yielded EIS data which suggested a decrease in the area of exposed fibers. This phenomenon is not well understood. Anodically polarized samples maintained a planar electrode response indicating uniform ablation which may have been caused by fiber and matrix oxidation. Samples exposed to caustic solutions also exhibited planar behavior attributed to general degradation of the BMI matrix. Galvanic couples with active metals yielded data with attributes of porous electrode behavior as well as characteristics associated with the anodic response. Couples with titanium caused changes in the response similar to those for low cathodic overpotentials. It is not known if these changes are harmful or benign.
Book Synopsis Environmental Durability of Graphite/epoxy Composites by : Christopher C. Pauly
Download or read book Environmental Durability of Graphite/epoxy Composites written by Christopher C. Pauly and published by . This book was released on 2002 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing acceptance and incorporation of fiber-reinforced polymer matrix composites (PMCs) as engineering construction materials have led many to look to the infrastructure as an application for these versatile materials. One such system is pultruded graphite fiber-reinforced epoxy (graphite/epoxy). Some PMC systems degrade when subjected to environmental conditions (e.g., moisture, stress, UV light, electrochemical polarization). These variables are typically studied either singularly or in series, but in real applications (e.g., aerospace, marine, infrastructure), these materials are subjected to many of these conditions simultaneously. To simulate field conditions, this study investigated the combined effects of an aqueous environment, electrochemical polarization, and applied bending stress on the durability of a pultruded graphite/epoxy composite. The findings indicate that graphite/epoxy composites cannot be assumed to be insensitive to degradation by environmental variables. Further, electrochemical polarization, as might occur with contact with a metal such as a fastener, can accelerate degradation. This damage requires the presence of moisture. Chloride and sulfate concentrations in rain are sufficient to establish an electrolyte within creviced regions, but deicing salts would overtake these as a contributor to conductivity. Further findings may be summarized as follows: 1.) Application of polarization in an aerated 0.6M NaCl environment led to breakdown of the fiber/matrix interface. The high pH environment created during the oxygen reduction reaction was necessary but not sufficient to create this breakdown, as the unpolarized specimen exposed to a pH 13 environment did not degrade. Cathodic polarization as would occur by coupling to steel or aluminum is required. 2.)Application of cathodic polarization did not significantly alter strength. Average measurements of shear strength, however, did decrease with the application of cathodic polarization for 70 and 90 days.
Book Synopsis Application of Electrochemical Impedance Spectroscopy as a Non-destructive Technique to Characterize and Detect Degradation of Carbon/nylon, 6 Composites in Aqueous Environments by : Ravishankar Haniyur
Download or read book Application of Electrochemical Impedance Spectroscopy as a Non-destructive Technique to Characterize and Detect Degradation of Carbon/nylon, 6 Composites in Aqueous Environments written by Ravishankar Haniyur and published by . This book was released on 1993 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis 3 ทศวรรษแห่งการสถาปนาคณะวิทยาศาสตร์ มหาวิทยาลัยเกษตรศาสตร์ 9 มีนาคม 2539 by :
Download or read book 3 ทศวรรษแห่งการสถาปนาคณะวิทยาศาสตร์ มหาวิทยาลัยเกษตรศาสตร์ 9 มีนาคม 2539 written by and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Moisture Absorption and Stiffness Degradation of Carbon Fiber Reinforced Polymer Composite Specimens Exposed to Accelerated Environmental Aging Conditions by : Kyle J. Eyre
Download or read book Moisture Absorption and Stiffness Degradation of Carbon Fiber Reinforced Polymer Composite Specimens Exposed to Accelerated Environmental Aging Conditions written by Kyle J. Eyre and published by . This book was released on 2007 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the moisture absorption and stiffness degradation studies, both fabric and plate CFRP were evaluated utilizing different epoxy resin systems. Specimens were exposed to: dry control (DC) conditions, and immersed in water at: 30°C (86°F), 50°C (122°F), and 60°C (140°F). Exposure times for the specimens ranged from 7 days to 50 days. The results of the two studies show that varying amounts of moisture absorption and stiffness degradation of the specimens (minor to significant) occurred over time. Comparisons of the performances of the different CFRP composite types were made.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modeling and Analysis of Performance Degradation in Unidirectional Carbon Fiber Reinforced Polymer Circuit Analog Absorbers from Environmental Damage by : Joseph O'Donnell
Download or read book Modeling and Analysis of Performance Degradation in Unidirectional Carbon Fiber Reinforced Polymer Circuit Analog Absorbers from Environmental Damage written by Joseph O'Donnell and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation explores the effects of various sources of damage or degradation on the microwave absorption properties of unidirectional carbon-fiber reinforced polymer (CFRP) circuit analog absorbers (CAA). Specifically, the effects of normal, blunt impact damage and extended exposure to salt water fog were studied. Multiple single-layer CFRP CAA samples were fabricated using a wet-layup technique and are then subjected to controlled degradation scenarios. The unidirectional CFRP was characterized by its complex relative permittivity and surface impedance properties using a free-space measurement system. Any changes to these properties were tracked and measured throughout the degradation process. Transmission-line and full-wave models provide further insight to electromagnetic and physical changes occurring to the CAA samples. Related topics are explored to acknowledge these designs and to lay a foundation for CAA operation. A brute-force sensitivity analysis is performed for CFRP CAAs. A descriptive method to characterize and quantify deterioration in CFRP CAAs is introduced. In summary, the research focuses on analyzing and modeling the effects of these performance degrading events by applying relevant electromagnetic models, comparing simulation results to experimental data, and quantifying the degradation using appropriate metrics.
Download or read book Engineered Materials Abstracts written by and published by . This book was released on 1995-07 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Carbon Fiber Content Measurement in Composite by : Qiushi Wang
Download or read book Carbon Fiber Content Measurement in Composite written by Qiushi Wang and published by . This book was released on 2015 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon fiber reinforced polymers (CFRPs) have been widely used in various structural applications in industries such as aerospace and automotive because of their high specific stiffness and specific strength. Their mechanical properties are strongly influenced by the carbon fiber content in the composites. Measurement of the carbon fiber content in CFRPs is essential for product quality control and process optimization. In this work, a novel carbonization-in-nitrogen method (CIN) is developed to characterize the fiber content in carbon fiber reinforced thermoset and thermoplastic composites. In this method, a carbon fiber composite sample is carbonized in a nitrogen environment at elevated temperatures, alongside a neat resin sample. The carbon fibers are protected from oxidization while the resin (the neat resin and the resin matrix in the composite sample) is carbonized under the nitrogen environment. The residue of the carbonized neat resin sample is used to calibrate the resin carbonization rate and calculate the amount of the resin matrix in the composite sample. The new method has been validated on several thermoset and thermoplastic resin systems and found to yield an accurate measurement of fiber content in carbon fiber polymer composites. In order to further understand the thermal degradation behavior of the high temperature thermoplastic polymer during the carbonization process, the mechanism and the kinetic model of thermal degradation behavior of carbon fiber reinforced poly (phenylene sulfide) (CPPS) are studied using thermogravimetry analysis (TGA). The CPPS is subjected to TGA in an air and nitrogen atmosphere at heating rates from 5 to 40°C min-1. The TGA curves obtained in air are different from those in nitrogen. This demonstrates that weight loss occurs in a single stage in nitrogen but in two stages in air. To elucidate this difference, thermal decomposition kinetics is analyzed by applying the Kissinger, Flynn-Wall-Ozawa, Coat-Redfern and Malek methods. The activation energy ( Ea) of the solid-state process is determined to be 202 kJ mol-1in an oxidative atmosphere using Kissinger's method, which is 10-15 kJ mol-1more than the results calculated in a nitrogen atmosphere. The value of the activation energy obtained using Ozawa-Flynn methods is in agreement with that using the Kissinger method. Different degradation mechanisms are used to compare with this value. Based on the analytical result, the actual thermal degradation mechanism of the CPPS is a Dn deceleration type. The carbonization temperature range of the CPPS is the same as pure PPS resin.
Book Synopsis Assessment of Durability of Carbon/epoxy Composite Materials After Exposure to Elevated Temperatures and Immersion in Seawater for Navy Vessel Applications by : SoonKook Hong
Download or read book Assessment of Durability of Carbon/epoxy Composite Materials After Exposure to Elevated Temperatures and Immersion in Seawater for Navy Vessel Applications written by SoonKook Hong and published by . This book was released on 2010 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon Fiber-Reinforced Polymer (CFRP) composites with epoxy matrices offer many advantages over conventional materials in terms of high strength-to-weight and high stiffness-to-weight ratios, design flexibility, corrosion resistance, and electromagnetic shielding for naval vessels in marine environments. However, the risk of fire and related structural degradation represent a challenge to the structural assessment of high performance composite structures. The accurate assessment of the deterioration and degradation of a composite structure subjected to elevated temperatures is vital in the planning for maintenance of mission critical components. In this research, carbon/epoxy composite materials have been thermally aged at nine (9) different temperatures for up to 72 hours of ageing time. In order to determine the residual mechanical properties of the specimens exposed to elevated temperatures, tensile, flexure, off-axis shear, and short beam shear tests were conducted in accordance with ASTM test procedures. In addition, the viscoelastic behavior and dynamic properties of these composites at varying ageing times and temperatures were found using Dynamic Mechanical Thermal Analysis (DMTA) and Differential Scanning Calorimetry (DSC). ThermoGravimetric Analysis (TGA) was performed to analyze the characteristics of thermal decomposition and Scanning Electron Microscopy (SEM) images were taken to investigate failure mechanisms such as interfacial debonding, delamination, and fiber fracture. Since polymer composite used in marine environments can easily be exposed to moisture related to high relative humidity and immersion, degradation mechanisms related to moisture were investigated on specimens immersed in seawater and deionized water for 72 weeks after exposure to selected regimes of elevated temperature using gravimetric analysis, SEM and short beam shear test. Finally, well-established prediction models such as Arrhenius rate model, Time-Temperature Superposition model and Weibull statistical strength model were used with experimental data to estimate characteristic associated with long-term service life.
