The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Kimiyoshi Naito - One of the best experts on this subject based on the ideXlab platform.
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Tensile Properties and Fracture Behavior of Different Carbon Nanotube-Grafted Polyacrylonitrile-Based Carbon Fibers
Journal of Materials Engineering and Performance, 2014Co-Authors: Kimiyoshi NaitoAbstract:The tensile properties and fracture behavior of different carbon nanotube (CNT)-grafted polyacrylonitrile-based (T1000GB) single carbon fibers were investigated. Grafting of CNTs was achieved via chemical vapor deposition (CVD). When Fe(C_5H_5)_2 (also applied via CVD) was used as the catalyst, the tensile strength and Weibull Modulus of the carbon fibers were improved, possibly due to the growth of dense CNT networks on the carbon fibers, which may have led to a reduction in the number of strength-limiting defects. Separately, at lower concentrations of an Fe(NO_3)_3·9H_2O catalyst in ethanol, which was applied via dipping, the tensile strength of CNT-grafted fibers was nearly identical to that of the as-received fibers, although the Weibull Modulus was higher. For higher concentrations of the Fe(NO_3)_3·9H_2O catalyst, however, the tensile strength and the Weibull Modulus were lower than those for the as-received material. Although the density of the CNT network increased with the concentration of the Fe(NO_3)_3·9H_2O catalyst in the ethanol solution, heating of the ethanolic Fe(NO_3)_3·9H_2O catalyst solution generated nitric acid (HNO_3) due to decomposition, which damaged the fiber surfaces, resulting in an increase in the number of flaws and consequently a reduction in the tensile strength. Therefore, the tensile strength and Weibull Modulus of CNT-grafted carbon fibers vary due to the combination of these effects and as a function of the catalyst concentration.
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Effect of Strain Rate on Tensile Properties of Carbon Fiber Epoxy-Impregnated Bundle Composite
Journal of Materials Engineering and Performance, 2014Co-Authors: Kimiyoshi NaitoAbstract:The tensile tests for high tensile strength polyacrylonitrile (PAN)-based (T1000GB) carbon fiber epoxy-impregnated bundle composite at various strain rates ranging from 3.33 × 10^−5 to 6.0 × 10^2 s^−1 (various crosshead speeds ranging from 8.33 × 10^−7 to 1.5 × 10^1 m/s) were investigated. The statistical distributions of the tensile strength were also evaluated. The results clearly demonstrated that the tensile strength of bundle composite slightly increased with an increase in the strain rate (crosshead speed) and the Weibull Modulus of tensile strength for the bundle composite decreased with an increase in the strain rate (crosshead speed), there is a linear relation between the Weibull Modulus and the average tensile strength on log-log scale.
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The effect of surface modification with carbon nanotubes upon the tensile strength and Weibull Modulus of carbon fibers
Journal of Materials Science, 2012Co-Authors: Kimiyoshi Naito, Jennming Yang, Yuta Inoue, Hiroshi FukudaAbstract:Carbon fibers are widely used as reinforcements in composite materials because of their high specific strength and Modulus. Today, a number of ultrahigh strength polyacrylonitrile (PAN)-based (more than 6 GPa), and ultrahigh Modulus pitch-based (more than 900 GPa) carbon fibers have been commercially available. In contrast, carbon nanotube (CNT) with the extremely high tensile strength have attracted attention as reinforcements. An interesting technique to modify the carbon fiber is CNT grafting on the carbon fiber surface. CNT-grafted carbon fibers offer the opportunity to add the potential benefits of nanoscale reinforcement to well-established fibrous composites to create micro-nano multiscale hybrid composites. In the present study, the tensile properties of CNT grown on T1000GB PAN- and K13D pitch-based carbon fibers have been investigated. Single filament tensile test at gauge lengths of 1, 5, and 25 mm were conducted. The effect of gauge length on tensile strength and Weibull Modulus of CNT-grafted PAN- and pitch-based carbon fibers were evaluated. It was found that grafting of CNT improves the tensile strength and Weibull Modulus of PAN- and pitch-based carbon fibers with longer gauge length (≥5 mm). The results also clearly show that for CNT-grafted and as-received PAN- and pitch-based carbon fibers, there is a linear relation between the Weibull Modulus and the average tensile strength on log–log scale.
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Tensile properties and Weibull Modulus of some high-performance polymeric fibers
Journal of Applied Polymer Science, 2012Co-Authors: Kimiyoshi NaitoAbstract:The tensile properties and fracture behavior of poly-(para-phenylene-2,6-benzobisoxazole), poly-(para-phenylene terephthalamide), co-poly-(para-phenylene-3,4′-oxydiphenylene terephthalamide), polyarylate, polyethylene, and poly(lactic acid) high-performance polymeric fibers have been investigated. The Weibull statistical distributions of the tensile strength were also characterized. The results clearly show that for various types of high-performance polymer fibers, the Weibull Modulus decreases with an increase in the tensile Modulus, the tensile strength, and inverse of the failure strain. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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tensile properties of high strength polyacrylonitrile pan based and high Modulus pitch based hybrid carbon fibers reinforced epoxy matrix composite
Journal of Materials Science, 2012Co-Authors: Kimiyoshi Naito, J Yang, Yutaka KagawaAbstract:The tensile properties of high strength polyacrylonitrile-based (IM600) and high Modulus pitch-based (K13D) hybrid carbon fibers-reinforced epoxy matrix composite (CFRP) were investigated. Fiber orientation of the hybrid CFRP specimen was set to [0(IM600)/0(K13D)]2S. The fiber volume fraction of the hybrid CFRP specimen was 55.7 vol% (IM600: 29.3 vol%, K13D: 26.4 vol%). The tensile stress–strain curve of the hybrid CFRP specimen shows a complicated shape (jagged trace). By the high Modulus K13D CFRP layers, the hybrid CFRP specimen shows the intermediate Modulus in the initial stage of loading. Subsequently, when the K13D CFRP layers begin to fail, the high strength IM600 CFRP layers would hold the load (strength) and the material continues to endure high load without instantaneous failure. Because higher strength fiber can help the load for a certain time after failure occur, the hybrid composite could be considered one example of a material possessing preventing instantaneous failure. The Weibull statistical distributions of the mono (IM600 and K13D) and the hybrid CFRP specimens were also examined. The Weibull Modulus for the mono CFRP specimens was calculated to be 22.9 for the IM600 CFRP specimen and 14.4 for the K13D CFRP specimen, respectively. The Weibull Modulus for the hybrid CFRP specimen was calculated to be 39.6 for the initial fracture strength and 20.6 for the tensile fracture strength, respectively. The Weibull Modulus for the initial fracture strength is higher than that for the K13D CFRP specimen and the Weibull Modulus for the tensile fracture strength is almost similar to that for the IM600 CFRP specimen.
Yutaka Kagawa - One of the best experts on this subject based on the ideXlab platform.
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tensile properties of high strength polyacrylonitrile pan based and high Modulus pitch based hybrid carbon fibers reinforced epoxy matrix composite
Journal of Materials Science, 2012Co-Authors: Kimiyoshi Naito, J Yang, Yutaka KagawaAbstract:The tensile properties of high strength polyacrylonitrile-based (IM600) and high Modulus pitch-based (K13D) hybrid carbon fibers-reinforced epoxy matrix composite (CFRP) were investigated. Fiber orientation of the hybrid CFRP specimen was set to [0(IM600)/0(K13D)]2S. The fiber volume fraction of the hybrid CFRP specimen was 55.7 vol% (IM600: 29.3 vol%, K13D: 26.4 vol%). The tensile stress–strain curve of the hybrid CFRP specimen shows a complicated shape (jagged trace). By the high Modulus K13D CFRP layers, the hybrid CFRP specimen shows the intermediate Modulus in the initial stage of loading. Subsequently, when the K13D CFRP layers begin to fail, the high strength IM600 CFRP layers would hold the load (strength) and the material continues to endure high load without instantaneous failure. Because higher strength fiber can help the load for a certain time after failure occur, the hybrid composite could be considered one example of a material possessing preventing instantaneous failure. The Weibull statistical distributions of the mono (IM600 and K13D) and the hybrid CFRP specimens were also examined. The Weibull Modulus for the mono CFRP specimens was calculated to be 22.9 for the IM600 CFRP specimen and 14.4 for the K13D CFRP specimen, respectively. The Weibull Modulus for the hybrid CFRP specimen was calculated to be 39.6 for the initial fracture strength and 20.6 for the tensile fracture strength, respectively. The Weibull Modulus for the initial fracture strength is higher than that for the K13D CFRP specimen and the Weibull Modulus for the tensile fracture strength is almost similar to that for the IM600 CFRP specimen.
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The effect of gauge length on tensile strength and Weibull Modulus of polyacrylonitrile (PAN)- and pitch-based carbon fibers
Journal of Materials Science, 2012Co-Authors: Kimiyoshi Naito, Jennming Yang, Yoshihisa Tanaka, Yutaka KagawaAbstract:Carbon fibers are widely used as a reinforcement in composite materials because of their high specific strength and Modulus. Current trends toward the development of carbon fibers have been driven in two directions; ultrahigh tensile strength fiber with a fairly high strain to failure (~2%), and ultrahigh Modulus fiber with high thermal conductivity. Today, a number of ultrahigh strength polyacrylonitrile (PAN)-based (more than 6 GPa), and ultrahigh Modulus pitch-based (more than 900 GPa) carbon fibers have been commercially available. In this study, the tensile strengths of PAN- and pitch-based carbon fibers have been investigated using a single filament tensile test at various gauge lengths ranging from 1 to 250 mm. Carbon fibers used in this study were ultrahigh strength PAN-based (T1000GB, IM600), a high strength PAN-based (T300), a high Modulus PAN-based (M60JB), an ultrahigh Modulus pitch-based (K13D), and a high ductility pitch-based (XN-05) carbon fibers. The statistical distributions of the tensile strength were characterized. It was found that the Weibull Modulus and the average tensile strength increased with decreasing gauge length, a linear relation between the Weibull Modulus, the average tensile strength and the gauge length was established on log–log scale. The results also clearly show that for PAN- and pitch-based carbon fibers, there is a linear relation between the Weibull Modulus and the average tensile strength on log–log scale.
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the effect of a compliant polyimide nanocoating on the tensile properties of a high strength pan based carbon fiber
Composites Science and Technology, 2009Co-Authors: Tamaki Naganuma, Kimiyoshi Naito, Junro Kyono, Daisuke Sasakura, Yutaka Kagawa, Jennming YangAbstract:Abstract The effect of a compliant polyimide nanocoating on the tensile strength of a polyacrylonitrile-based high tensile strength (T1000GB) carbon fiber was investigated. The pyromellitic dianhydride/4-4′-oxydianiline polyimide nanocoating was deposited by high-temperature vapor deposition polymerization. The thickness of the polyimide coating was about 100 nm. The tensile strength and Weibull Modulus of nanocoated and uncoated fiber bundles were evaluated using a polyimide-impregnated bundle-composite. The results clearly demonstrated that the compliant polyimide nanocoating is effective in improving the tensile strength and Weibull Modulus of T1000GB carbon fiber.
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tensile properties of ultrahigh strength pan based ultrahigh Modulus pitch based and high ductility pitch based carbon fibers
Carbon, 2008Co-Authors: Kimiyoshi Naito, Yoshihisa Tanaka, J Yang, Yutaka KagawaAbstract:The tensile properties and fracture behavior of ultrahigh tensile strength PAN-based (T1000GB), ultrahigh Modulus pitch-based (K13D) and high ductility pitch-based (XN-05) carbon fibers have been investigated. The statistical distributions of the tensile strength were characterized. The Weibull Modulus for the T1000GB, K13D and XN-05 fibers were calculated to be 5.9, 4.2 and 7.9, respectively. The results clearly show that for PAN- and pitch-based carbon fibers, the Weibull Modulus decreases with an increase in the tensile Modulus and the mean tensile strength.
D. M Wilson - One of the best experts on this subject based on the ideXlab platform.
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Statistical tensile strength of Nextel^TM 610 and Nextel^TM 720 fibres
Journal of Materials Science, 1997Co-Authors: D. M WilsonAbstract:The properties of fibre-reinforced composites are dependent not only on the strength of the reinforcement fibre but also the distribution of fibre strength. In this study, the single filament strength of several lots of Nextel^TM 610 and Nextel^TM 720 ceramic fibres was measured. Fracture statistics were correlated with the effects of gauge length and diameter variation, and the Weibull Modulus was calculated using several different techniques. It was found that the measured Weibull Modulus at a single gauge length did not accurately predict either the gauge length or diameter dependence of tensile strength.
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Statistical tensile strength of Nextel TM 610 and Nextel TM 720 fibres
Journal of Materials Science, 1997Co-Authors: D. M WilsonAbstract:The properties of fibre-reinforced composites are dependent not only on the strength of the reinforcement fibre but also the distribution of fibre strength. In this study, the single filament strength of several lots of NextelTM 610 and NextelTM 720 ceramic fibres was measured. Fracture statistics were correlated with the effects of gauge length and diameter variation, and the Weibull Modulus was calculated using several different techniques. It was found that the measured Weibull Modulus at a single gauge length did not accurately predict either the gauge length or diameter dependence of tensile strength.
Ian Davies - One of the best experts on this subject based on the ideXlab platform.
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Unbiased estimation of Weibull Modulus using linear least squares analysis—A systematic approach
Journal of the European Ceramic Society, 2017Co-Authors: Ian DaviesAbstract:Abstract The wide applicability of the Weibull distribution to fields such as hydrology and materials science has led to a large number of probability estimators being proposed, in particular for the widely used technique of obtaining the Weibull Modulus, m, using unweighted linear least squares (LLS) analysis. In this work a systematic approach using the Monte Carlo method has been taken to determining the optimal probability estimators for unbiased estimation of m (mean, median and mode) using the general equation F = ( i − a ) / ( N + b ) whilst simultaneously minimising the coefficient of variation for each of the average values. A wide range of a and b values were investigated within the region 0 ≤ a ≤ 1 and 1 ≤ b ≤ 1000 with the form of F = ( i − a ) / ( N + 1 ) being chosen as the recommend probability estimator equation due to its simplicity and relatively small coefficient of variation. Values of a as a function of N were presented for the mean, median and mode m values.
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unbiased estimation of Weibull Modulus using linear least squares analysis a systematic approach
Journal of The European Ceramic Society, 2017Co-Authors: Ian DaviesAbstract:Abstract The wide applicability of the Weibull distribution to fields such as hydrology and materials science has led to a large number of probability estimators being proposed, in particular for the widely used technique of obtaining the Weibull Modulus, m, using unweighted linear least squares (LLS) analysis. In this work a systematic approach using the Monte Carlo method has been taken to determining the optimal probability estimators for unbiased estimation of m (mean, median and mode) using the general equation F = ( i − a ) / ( N + b ) whilst simultaneously minimising the coefficient of variation for each of the average values. A wide range of a and b values were investigated within the region 0 ≤ a ≤ 1 and 1 ≤ b ≤ 1000 with the form of F = ( i − a ) / ( N + 1 ) being chosen as the recommend probability estimator equation due to its simplicity and relatively small coefficient of variation. Values of a as a function of N were presented for the mean, median and mode m values.
Jennming Yang - One of the best experts on this subject based on the ideXlab platform.
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The effect of surface modification with carbon nanotubes upon the tensile strength and Weibull Modulus of carbon fibers
Journal of Materials Science, 2012Co-Authors: Kimiyoshi Naito, Jennming Yang, Yuta Inoue, Hiroshi FukudaAbstract:Carbon fibers are widely used as reinforcements in composite materials because of their high specific strength and Modulus. Today, a number of ultrahigh strength polyacrylonitrile (PAN)-based (more than 6 GPa), and ultrahigh Modulus pitch-based (more than 900 GPa) carbon fibers have been commercially available. In contrast, carbon nanotube (CNT) with the extremely high tensile strength have attracted attention as reinforcements. An interesting technique to modify the carbon fiber is CNT grafting on the carbon fiber surface. CNT-grafted carbon fibers offer the opportunity to add the potential benefits of nanoscale reinforcement to well-established fibrous composites to create micro-nano multiscale hybrid composites. In the present study, the tensile properties of CNT grown on T1000GB PAN- and K13D pitch-based carbon fibers have been investigated. Single filament tensile test at gauge lengths of 1, 5, and 25 mm were conducted. The effect of gauge length on tensile strength and Weibull Modulus of CNT-grafted PAN- and pitch-based carbon fibers were evaluated. It was found that grafting of CNT improves the tensile strength and Weibull Modulus of PAN- and pitch-based carbon fibers with longer gauge length (≥5 mm). The results also clearly show that for CNT-grafted and as-received PAN- and pitch-based carbon fibers, there is a linear relation between the Weibull Modulus and the average tensile strength on log–log scale.
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The effect of gauge length on tensile strength and Weibull Modulus of polyacrylonitrile (PAN)- and pitch-based carbon fibers
Journal of Materials Science, 2012Co-Authors: Kimiyoshi Naito, Jennming Yang, Yoshihisa Tanaka, Yutaka KagawaAbstract:Carbon fibers are widely used as a reinforcement in composite materials because of their high specific strength and Modulus. Current trends toward the development of carbon fibers have been driven in two directions; ultrahigh tensile strength fiber with a fairly high strain to failure (~2%), and ultrahigh Modulus fiber with high thermal conductivity. Today, a number of ultrahigh strength polyacrylonitrile (PAN)-based (more than 6 GPa), and ultrahigh Modulus pitch-based (more than 900 GPa) carbon fibers have been commercially available. In this study, the tensile strengths of PAN- and pitch-based carbon fibers have been investigated using a single filament tensile test at various gauge lengths ranging from 1 to 250 mm. Carbon fibers used in this study were ultrahigh strength PAN-based (T1000GB, IM600), a high strength PAN-based (T300), a high Modulus PAN-based (M60JB), an ultrahigh Modulus pitch-based (K13D), and a high ductility pitch-based (XN-05) carbon fibers. The statistical distributions of the tensile strength were characterized. It was found that the Weibull Modulus and the average tensile strength increased with decreasing gauge length, a linear relation between the Weibull Modulus, the average tensile strength and the gauge length was established on log–log scale. The results also clearly show that for PAN- and pitch-based carbon fibers, there is a linear relation between the Weibull Modulus and the average tensile strength on log–log scale.
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the effect of a compliant polyimide nanocoating on the tensile properties of a high strength pan based carbon fiber
Composites Science and Technology, 2009Co-Authors: Tamaki Naganuma, Kimiyoshi Naito, Junro Kyono, Daisuke Sasakura, Yutaka Kagawa, Jennming YangAbstract:Abstract The effect of a compliant polyimide nanocoating on the tensile strength of a polyacrylonitrile-based high tensile strength (T1000GB) carbon fiber was investigated. The pyromellitic dianhydride/4-4′-oxydianiline polyimide nanocoating was deposited by high-temperature vapor deposition polymerization. The thickness of the polyimide coating was about 100 nm. The tensile strength and Weibull Modulus of nanocoated and uncoated fiber bundles were evaluated using a polyimide-impregnated bundle-composite. The results clearly demonstrated that the compliant polyimide nanocoating is effective in improving the tensile strength and Weibull Modulus of T1000GB carbon fiber.
