The Experts below are selected from a list of 5355 Experts worldwide ranked by ideXlab platform
Chun-gon Kim - One of the best experts on this subject based on the ideXlab platform.
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tensile response of Graphite Epoxy Composites at low temperatures
Composite Structures, 2007Co-Authors: Myunggon Kim, Chun-gon Kim, Sangguk Kang, Cheolwon KongAbstract:Abstract In this study, the tensile properties of a T700/Epoxy composite, which had been cycled with thermo-mechanical loads at low temperatures, were measured using an environmental test chamber. Thermo-mechanical tensile cyclic loading (up to 10 cycles) was applied to T700/Epoxy unidirectional laminates at room temperature (RT) to −50 °C, RT to −100 °C, and RT to −150 °C (CT), respectively. Results showed that tensile stiffness significantly increased as temperature decreased, while the thermo-mechanical cycling had little influence on it. Tensile strength, however, decreased as temperature decreased down to CT, while the decreasing rate of strength was reduced after CT cycling. For the analysis of the test results, the coefficients of thermal expansion (CTEs) of the laminate composite specimen, both at RT and CT, were measured, and the interface between fiber and matrix was observed using SEM images.
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low earth orbit space environment simulation and its effects on Graphite Epoxy Composites
Composite Structures, 2006Co-Authors: Joo-hyun Han, Chun-gon KimAbstract:In this study, a low Earth orbit (LEO) space environment simulation facility, capable of simulating major LEO space environment constituents such as high vacuum, ultraviolet (UV) radiation, thermal cycling and atomic oxygen (AO) atmosphere, is introduced. Under the simulated LEO space environment, Graphite/Epoxy Composites, which are widely applied to space structures, were tested to study the LEO space environment effects on the Composites. Tensile properties, as well as mass loss of the Graphite/Epoxy Composites, after being exposed to AO atmosphere and the synergistic LEO space environment, were investigated. The surface morphology of the Composites under LEO space environment effects was also observed by scanning electron microscope (SEM). Experimental results showed that LEO environment and its synergistic effects cause considerable damage to the surface of Composites.
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Low earth orbit space environment simulation and its effects on Graphite/Epoxy Composites
Composite Structures, 2006Co-Authors: Joo-hyun Han, Chun-gon KimAbstract:In this study, a low Earth orbit (LEO) space environment simulation facility, capable of simulating major LEO space environment constituents such as high vacuum, ultraviolet (UV) radiation, thermal cycling and atomic oxygen (AO) atmosphere, is introduced. Under the simulated LEO space environment, Graphite/Epoxy Composites, which are widely applied to space structures, were tested to study the LEO space environment effects on the Composites. Tensile properties, as well as mass loss of the Graphite/Epoxy Composites, after being exposed to AO atmosphere and the synergistic LEO space environment, were investigated. The surface morphology of the Composites under LEO space environment effects was also observed by scanning electron microscope (SEM). Experimental results showed that LEO environment and its synergistic effects cause considerable damage to the surface of Composites.
Sylvanus N. Wosu - One of the best experts on this subject based on the ideXlab platform.
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Effects of the loading direction on high strain rate behavior of woven Graphite/Epoxy Composites
Journal of Materials Science Research, 2012Co-Authors: Fatih Turan, Mohammad Reza Allazadeh, Sylvanus N. WosuAbstract:Effects of the loading direction on high strain rate behavior of cylindrical woven Graphite/Epoxy Composites are presented. Compressive split Hopkinson pressure bar (SHPB) was used for high strain rate experiments. Cylindrical specimens were loaded diametrically and transversely at the impact energies of 67 J, 163 J, and 263 J. Micro Laser Raman spectroscopy and scanning electron microscopy (SEM) were used for surface characterization. It is observed that diametrically loaded specimens show permanent plastic deformation with high ductility resulting in a catastrophic failure while transversely loaded specimens exhibit viscoplastic deformation with some recoverable damage. As a result of this, Raman peak shifted to higher values for the diametrically loaded fibers whereas almost no change was observed in the Raman shift of transversely loaded fibers.
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Effect of the contact geometry on high strain rate behavior of woven Graphite/Epoxy Composites
Journal of Materials Science Research, 2011Co-Authors: Fatih Turan, Mohammad Reza Allazadeh, Sylvanus N. WosuAbstract:Effects of the contact geometry on high strain rate failure behavior of woven Graphite/Epoxy Composites are presented. Compressive split Hopkinson pressure bar was used for high strain rate experiments. Woven Graphite/Epoxy Composites were loaded transversely using two different contact geometries at the impact energies of 67 J and 163 J. It is observed that smaller contact area gives higher damage, resulting in higher energy absorption, elastic modulus and strain rate and peak stress in the specimens.
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High Strain Rate Compressive Tests on Woven Graphite Epoxy Composites
Applied Composite Materials, 2011Co-Authors: Mohammad Reza Allazadeh, Sylvanus N. WosuAbstract:The behavior of composite materials may be different when they are subjected to high strain rate load. Penetrating split Hopkinson pressure bar (P-SHPB) is a method to impose high strain rate on specimen in the laboratory experiments. This research work studied the response of the thin circular shape specimens, made out of woven Graphite Epoxy Composites, to high strain rate impact load. The stress-strain relationships and behavior of the specimens were investigated during the compressive dynamic tests for strain rates as high as 3200 s^−1. One dimensional analysis was deployed for analytical calculations since the experiments fulfilled the ratio of diameter to length of bars condition in impact load experiments. The mechanics of dynamic failure was studied and the results showed the factors which govern the failure mode in high strain deformation via absorbed energy by the specimen. In this paper, the relation of particle velocity with perforation depth was discussed for woven Graphite Epoxy specimens.
A. Shalwan - One of the best experts on this subject based on the ideXlab platform.
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Correlation between Mechanical Properties with Specific Wear Rate and the Coefficient of Friction of Graphite/Epoxy Composites
Materials, 2015Co-Authors: S. Alajmi, A. ShalwanAbstract:The correlation between the mechanical properties of Fillers/Epoxy Composites and their tribological behavior was investigated. Tensile, hardness, wear, and friction tests were conducted for Neat Epoxy (NE), Graphite/Epoxy Composites (GE), and Data Palm Fiber/Epoxy with or without Graphite Composites (GFE and FE). The correlation was made between the tensile strength, the modulus of elasticity, elongation at the break, and the hardness, as an individual or a combined factor, with the specific wear rate (SWR) and coefficient of friction (COF) of Composites. In general, Graphite as an additive to polymeric composite has had an eclectic effect on mechanical properties, whereas it has led to a positive effect on tribological properties, whilst date palm fibers (DPFs), as reinforcement for polymeric composite, promoted a mechanical performance with a slight improvement to the tribological performance. Statistically, this study reveals that there is no strong confirmation of any marked correlation between the mechanical and the specific wear rate of filler/Epoxy Composites. There is, however, a remarkable correlation between the mechanical properties and the friction coefficient of filler/Epoxy Composites.
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correlation between mechanical properties with specific wear rate and the coefficient of friction of Graphite Epoxy Composites
Materials, 2015Co-Authors: Mahdi S Alajmi, A. ShalwanAbstract:The correlation between the mechanical properties of Fillers/Epoxy Composites and their tribological behavior was investigated. Tensile, hardness, wear, and friction tests were conducted for Neat Epoxy (NE), Graphite/Epoxy Composites (GE), and Data Palm Fiber/Epoxy with or without Graphite Composites (GFE and FE). The correlation was made between the tensile strength, the modulus of elasticity, elongation at the break, and the hardness, as an individual or a combined factor, with the specific wear rate (SWR) and coefficient of friction (COF) of Composites. In general, Graphite as an additive to polymeric composite has had an eclectic effect on mechanical properties, whereas it has led to a positive effect on tribological properties, whilst date palm fibers (DPFs), as reinforcement for polymeric composite, promoted a mechanical performance with a slight improvement to the tribological performance. Statistically, this study reveals that there is no strong confirmation of any marked correlation between the mechanical and the specific wear rate of filler/Epoxy Composites. There is, however, a remarkable correlation between the mechanical properties and the friction coefficient of filler/Epoxy Composites.
Jun Wang - One of the best experts on this subject based on the ideXlab platform.
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a study of delamination on Graphite Epoxy Composites in abrasive waterjet machining
Composites Part A-applied Science and Manufacturing, 2008Co-Authors: D K Shanmugam, Thai Nguyen, Jun WangAbstract:Abstract Delamination is a major component defect when machining Composites or layered materials. This study aims to explore the mechanism of delamination in Graphite/Epoxy Composites under abrasive waterjet (AWJ) machining. It is found that crack tips are generated by the shock wave impact of the waterjet at the initial cutting stage, while delamination is a result of water penetration into the crack tips that promotes water-wedging and abrasive embedment. Based on an energy conservation approach, a semi-analytical model is developed to predict the maximum delamination length generated by an AWJ. The model prediction is found in good agreement with the experimental data and can be used as a practical guide for process planning to minimise or eliminate the delamination defects on the components in AWJ machining of Graphite/Epoxy Composites.
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A study of delamination on Graphite/Epoxy Composites in abrasive waterjet machining
Composites Part A-applied Science and Manufacturing, 2008Co-Authors: D K Shanmugam, Thai Nguyen, Jun WangAbstract:Abstract Delamination is a major component defect when machining Composites or layered materials. This study aims to explore the mechanism of delamination in Graphite/Epoxy Composites under abrasive waterjet (AWJ) machining. It is found that crack tips are generated by the shock wave impact of the waterjet at the initial cutting stage, while delamination is a result of water penetration into the crack tips that promotes water-wedging and abrasive embedment. Based on an energy conservation approach, a semi-analytical model is developed to predict the maximum delamination length generated by an AWJ. The model prediction is found in good agreement with the experimental data and can be used as a practical guide for process planning to minimise or eliminate the delamination defects on the components in AWJ machining of Graphite/Epoxy Composites.
Joo-hyun Han - One of the best experts on this subject based on the ideXlab platform.
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low earth orbit space environment simulation and its effects on Graphite Epoxy Composites
Composite Structures, 2006Co-Authors: Joo-hyun Han, Chun-gon KimAbstract:In this study, a low Earth orbit (LEO) space environment simulation facility, capable of simulating major LEO space environment constituents such as high vacuum, ultraviolet (UV) radiation, thermal cycling and atomic oxygen (AO) atmosphere, is introduced. Under the simulated LEO space environment, Graphite/Epoxy Composites, which are widely applied to space structures, were tested to study the LEO space environment effects on the Composites. Tensile properties, as well as mass loss of the Graphite/Epoxy Composites, after being exposed to AO atmosphere and the synergistic LEO space environment, were investigated. The surface morphology of the Composites under LEO space environment effects was also observed by scanning electron microscope (SEM). Experimental results showed that LEO environment and its synergistic effects cause considerable damage to the surface of Composites.
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Low earth orbit space environment simulation and its effects on Graphite/Epoxy Composites
Composite Structures, 2006Co-Authors: Joo-hyun Han, Chun-gon KimAbstract:In this study, a low Earth orbit (LEO) space environment simulation facility, capable of simulating major LEO space environment constituents such as high vacuum, ultraviolet (UV) radiation, thermal cycling and atomic oxygen (AO) atmosphere, is introduced. Under the simulated LEO space environment, Graphite/Epoxy Composites, which are widely applied to space structures, were tested to study the LEO space environment effects on the Composites. Tensile properties, as well as mass loss of the Graphite/Epoxy Composites, after being exposed to AO atmosphere and the synergistic LEO space environment, were investigated. The surface morphology of the Composites under LEO space environment effects was also observed by scanning electron microscope (SEM). Experimental results showed that LEO environment and its synergistic effects cause considerable damage to the surface of Composites.
