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Michael R Wisnom - One of the best experts on this subject based on the ideXlab platform.
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fatigue behaviour of pseudo ductile unidirectional Thin Ply carbon epoxy glass epoxy hybrid composites
Composite Structures, 2019Co-Authors: Putu Suwarta, Marco L Longana, Gergely Czel, Mohamad Fotouhi, Michael R WisnomAbstract:Abstract This paper is the first detailed investigation of the fatigue behavior of pseudo-ductile unidirectional (UD) Thin-Ply interlayer hybrids made of Thin-Ply carbon/epoxy plies sandwiched between standard thickness glass/epoxy plies under two scenarios: without any initial damage (pristine hybrids) and after the introduction of damage in the laminates by loading past the pseudo-yield point (overloaded hybrids). The laminates were subjected to different percentages of the critical stress level at which multiple fragmentation of the carbon plies was established (knee-point stress). The stress levels for fatigue delamination initiation and growth were evaluated experimentally. Based on the experimental work, it was observed that (1) when pristine hybrid composites were fatigued well below the carbon failure strain, at a stress level of 80% of the knee-point stress, there is no stiffness reduction after a significant number of cycles (105 cycles) (2) gradual stiffness reduction and very slow delamination growth was observed for pristine hybrid composites when fatigued at 90% of the knee-point stress, (3) when overloaded hybrid composites were fatigued at 90%, 80% and 70% of the knee-point stress, they did not fail immediately but delaminated slowly (4) the slow growth was due to the low energy release rate of the Thin-Ply hybrid composites (5) the strain energy release rate approach related to delamination rates provides a good way to characterize the fatigue damage accumulation of overloaded hybrid composites and as a basis to predict the fatigue life.
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Post-Impact Behaviour of Pseudo-Ductile Thin-Ply Angle-Ply Hybrid Composites
Materials, 2019Co-Authors: Alessia Prato, Marco L Longana, Ambreen Hussain, Michael R WisnomAbstract:This work experimentally explores the post-impact behaviour of Thin-Ply angle-Ply pseudo-ductile carbon fibre laminates subjected to tensile load. Indentation and low-speed impact tests were performed on standard tensile test specimens. Non-destructive tests were used to investigate the damage propagation. Digital Image Correlation (DIC) was adopted to detect the strain distribution during tensile tests. Post-damage pseudo-ductile behaviour was retained in angle-Ply hybrid composites subjected to tensile loading conditions.
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Compact tension test behaviour of Pseudo-ductile Thin-Ply carbon/ glass hybrids
2018Co-Authors: Mohamad Fotouhi, Meisam Jalalvand, Michael R WisnomAbstract:The aim of this work was to investigate the notched behaviour of Thin Ply pseudo-ductile carbon/glass hybrid laminates with in-plane Over-height Compact Tension (OCT) specimens. Therefore, a series of tests were performed on two different Thin-Ply carbon/glass hybrid configurations fabricated from Quasi Isotropic (QI) hybrid constituents and architectures. The first consisted of Thin Ply carbon M46JB/Thin Ply glass (X-strand) and the second Thin-Ply carbon TC35/standard thickness S-glass prepregs. For comparison, all glass and all carbon laminates were investigated as well. A detailed assessment of the damage evolution was carried out using X-ray Computed Tomography (CT). Results show that the hybrid configurations have a higher stiffness compared to the all glass samples. A progressive and gradual failure of the hybrids resulted in gradual load-pin opening displacement (POD) curves, where there was no significant sudden load-drop that happened for the all carbon laminates due to the catastrophic failure mechanisms. The damage in the hybrid configurations was visually detectable and agreed well with the CT-scan results, whereas it was not feasible to see the damage easily for the all glass and all carbon configurations.
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Bearing and bearing-bypass of pseudo-ductile Thin-Ply carbon/ glass hybrids
2018Co-Authors: Mohammad Fotouhi, Meisam Jalalvand, Michael R WisnomAbstract:The aim of this work was to investigate the bearing and bearing-bypass behaviour of Thin Ply pseudo-ductile carbon/glass hybrid laminates in tension. Therefore, a series of tests were performed based on ASTM D7248/D7248M–12 on a Quasi Isotropic (QI) Thin-Ply carbon/glass hybrid laminate consisting of Thin-Ply carbon TC35/standard thickness S-glass prepregs. For comparison, all S-glass and all TC35-carbon laminates were investigated as well. The results for the bearing tests showed that all the investigated configurations have a similar load-displacement manner with slight improvement in stiffness of the hybrid laminate compared with the all glass laminate. In the bearing tests, the hybrid and all-glass laminates experienced a mixed of shear out and bearing failure modes, whereas the all-carbon laminate experienced a mixture of shear out, bearing and cleavage failure modes. For the bearing-bypass tests, the hybrid laminate and all-glass laminates experienced higher displacement with a gradual failure compared with the all-carbon laminate that failed catastrophically with a sudden load drop. The hybrid configuration had the highest maximum load in the bypass loading and experienced a higher stiffness compared to the all-glass samples. The hybrid and all-glass laminates showed progressive and gradual failure modes in the bypass tests, with a mixture of shear out, bearing and net section failure modes, whereas the all-carbon laminate showed a mixture of bearing and net-section failure modes. Overall, the hybrid configuration showed similar mechanical properties to the baselines for the bearing tests. On the other hand, they behaved better than the all-carbon (higher displacement and more gradual failure) and better than the-all glass laminate (higher initial stiffness and maximum load).
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notch insensitive orientation dispersed pseudo ductile Thin Ply carbon glass hybrid laminates
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Mohamad Fotouhi, Meisam Jalalvand, Michael R WisnomAbstract:Notch sensitivity, free edge delamination and brittle failure are limiting factors for the wider use of conventional composite laminates. In our previous study, a hybrid layup concept with the different materials blocked together but with dispersed orientations was successfully used to design pseudo-ductile hybrid composites with no free-edge delamination. This study introduces a comprehensive set of designed and characterised orientation-dispersed pseudo-ductile Thin-Ply hybrid composites to address notch sensitivity, another important limiting factor in conventional composite laminates. Un-notched, open-hole and sharp notched tension tests were performed on three different Thin-Ply carbon/glass hybrid configurations. The investigated laminates showed a successful pseudo-ductile un-notched behaviour with improved notch-insensitivity and suppression of free-edge delamination that was an undesirable damage mode in previously investigated hybrids with plies of the same orientation blocked together. This notch insensitivity results from subcritical damage in the laminates due to the pseudo-ductile damage mechanisms, i.e. dispersed delamination and fragmentation. These damage mechanisms can eliminate stress concentrations near the notch and suppress the conventional damage mechanisms that govern the notched response of the laminates.
Meisam Jalalvand - One of the best experts on this subject based on the ideXlab platform.
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Fatigue behaviour of un-notched and open-hole quasi-isotropic pseudo-ductile Thin-Ply carbon/glass hybrid laminates
2019Co-Authors: Mohammad Fotouhi, Meisam Jalalvand, Putu Suwarta, Ross Jenkin, Micheal WisnomAbstract:This paper investigates fatigue behaviour of a QI composite made from Thin carbon plies and standard thickness glass plies. As illustrated in Fig. 2, this orientation-dispersed QI Thin-Ply carbon/glass hybrid laminate showed a successful pseudo-ductile un-notched behaviour with improved notch-insensitivity and suppression of free-edge delamination. In this study an experimental program has been carried out to investigate the damage development throughout the life of un-notched and open-hole Thin-Ply carbon/glass hybrid configurations consisting of Thin Ply T300 carbon/epoxy and S-glass/epoxy prepregs, before having any pseudo-ductile damage and at two different stress levels. The fatigued samples are illustrated in Figs. 3 and 4. The knee point is determined at the intersection of the lines fitted through the initial linear and the plateau parts of the individual stress-strain curves. It was observed that, for the un-notched samples, there is no stiffness reduction, after 100,000 cycles, for a stress level of 80% of the knee-point stress at which significant damage starts. By increasing the stress level to 90% of the knee point stress, there is a gradual stiffness reduction due to the appearance of matrix cracking and delamination.
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Compact tension test behaviour of Pseudo-ductile Thin-Ply carbon/ glass hybrids
2018Co-Authors: Mohamad Fotouhi, Meisam Jalalvand, Michael R WisnomAbstract:The aim of this work was to investigate the notched behaviour of Thin Ply pseudo-ductile carbon/glass hybrid laminates with in-plane Over-height Compact Tension (OCT) specimens. Therefore, a series of tests were performed on two different Thin-Ply carbon/glass hybrid configurations fabricated from Quasi Isotropic (QI) hybrid constituents and architectures. The first consisted of Thin Ply carbon M46JB/Thin Ply glass (X-strand) and the second Thin-Ply carbon TC35/standard thickness S-glass prepregs. For comparison, all glass and all carbon laminates were investigated as well. A detailed assessment of the damage evolution was carried out using X-ray Computed Tomography (CT). Results show that the hybrid configurations have a higher stiffness compared to the all glass samples. A progressive and gradual failure of the hybrids resulted in gradual load-pin opening displacement (POD) curves, where there was no significant sudden load-drop that happened for the all carbon laminates due to the catastrophic failure mechanisms. The damage in the hybrid configurations was visually detectable and agreed well with the CT-scan results, whereas it was not feasible to see the damage easily for the all glass and all carbon configurations.
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Bearing and bearing-bypass of pseudo-ductile Thin-Ply carbon/ glass hybrids
2018Co-Authors: Mohammad Fotouhi, Meisam Jalalvand, Michael R WisnomAbstract:The aim of this work was to investigate the bearing and bearing-bypass behaviour of Thin Ply pseudo-ductile carbon/glass hybrid laminates in tension. Therefore, a series of tests were performed based on ASTM D7248/D7248M–12 on a Quasi Isotropic (QI) Thin-Ply carbon/glass hybrid laminate consisting of Thin-Ply carbon TC35/standard thickness S-glass prepregs. For comparison, all S-glass and all TC35-carbon laminates were investigated as well. The results for the bearing tests showed that all the investigated configurations have a similar load-displacement manner with slight improvement in stiffness of the hybrid laminate compared with the all glass laminate. In the bearing tests, the hybrid and all-glass laminates experienced a mixed of shear out and bearing failure modes, whereas the all-carbon laminate experienced a mixture of shear out, bearing and cleavage failure modes. For the bearing-bypass tests, the hybrid laminate and all-glass laminates experienced higher displacement with a gradual failure compared with the all-carbon laminate that failed catastrophically with a sudden load drop. The hybrid configuration had the highest maximum load in the bypass loading and experienced a higher stiffness compared to the all-glass samples. The hybrid and all-glass laminates showed progressive and gradual failure modes in the bypass tests, with a mixture of shear out, bearing and net section failure modes, whereas the all-carbon laminate showed a mixture of bearing and net-section failure modes. Overall, the hybrid configuration showed similar mechanical properties to the baselines for the bearing tests. On the other hand, they behaved better than the all-carbon (higher displacement and more gradual failure) and better than the-all glass laminate (higher initial stiffness and maximum load).
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notch insensitive orientation dispersed pseudo ductile Thin Ply carbon glass hybrid laminates
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Mohamad Fotouhi, Meisam Jalalvand, Michael R WisnomAbstract:Notch sensitivity, free edge delamination and brittle failure are limiting factors for the wider use of conventional composite laminates. In our previous study, a hybrid layup concept with the different materials blocked together but with dispersed orientations was successfully used to design pseudo-ductile hybrid composites with no free-edge delamination. This study introduces a comprehensive set of designed and characterised orientation-dispersed pseudo-ductile Thin-Ply hybrid composites to address notch sensitivity, another important limiting factor in conventional composite laminates. Un-notched, open-hole and sharp notched tension tests were performed on three different Thin-Ply carbon/glass hybrid configurations. The investigated laminates showed a successful pseudo-ductile un-notched behaviour with improved notch-insensitivity and suppression of free-edge delamination that was an undesirable damage mode in previously investigated hybrids with plies of the same orientation blocked together. This notch insensitivity results from subcritical damage in the laminates due to the pseudo-ductile damage mechanisms, i.e. dispersed delamination and fragmentation. These damage mechanisms can eliminate stress concentrations near the notch and suppress the conventional damage mechanisms that govern the notched response of the laminates.
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Reduced tensile notch-sensitivity in pseudo-ductile Thin Ply composites
2018Co-Authors: Michael R Wisnom, Jonathan D Fuller, Mohammad Fotouhi, Gergely Czel, Meisam Jalalvand, Tamas RevAbstract:Pseudo-ductile Thin-Ply composites loaded in tension exhibit a non-linear stress-strain response with a plateau, analogous to yielding in a metal. This provides an alternative means for load redistribution at stress concentrations, giving reduced notch-sensitivity. The notched tensile response of both Thin-Ply hybrid and angle-Ply laminates is presented, and the failure mechanisms described and compared with those of conventional composites to explain the reduced notch sensitivity.
Gergely Czel - One of the best experts on this subject based on the ideXlab platform.
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fatigue behaviour of pseudo ductile unidirectional Thin Ply carbon epoxy glass epoxy hybrid composites
Composite Structures, 2019Co-Authors: Putu Suwarta, Marco L Longana, Gergely Czel, Mohamad Fotouhi, Michael R WisnomAbstract:Abstract This paper is the first detailed investigation of the fatigue behavior of pseudo-ductile unidirectional (UD) Thin-Ply interlayer hybrids made of Thin-Ply carbon/epoxy plies sandwiched between standard thickness glass/epoxy plies under two scenarios: without any initial damage (pristine hybrids) and after the introduction of damage in the laminates by loading past the pseudo-yield point (overloaded hybrids). The laminates were subjected to different percentages of the critical stress level at which multiple fragmentation of the carbon plies was established (knee-point stress). The stress levels for fatigue delamination initiation and growth were evaluated experimentally. Based on the experimental work, it was observed that (1) when pristine hybrid composites were fatigued well below the carbon failure strain, at a stress level of 80% of the knee-point stress, there is no stiffness reduction after a significant number of cycles (105 cycles) (2) gradual stiffness reduction and very slow delamination growth was observed for pristine hybrid composites when fatigued at 90% of the knee-point stress, (3) when overloaded hybrid composites were fatigued at 90%, 80% and 70% of the knee-point stress, they did not fail immediately but delaminated slowly (4) the slow growth was due to the low energy release rate of the Thin-Ply hybrid composites (5) the strain energy release rate approach related to delamination rates provides a good way to characterize the fatigue damage accumulation of overloaded hybrid composites and as a basis to predict the fatigue life.
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Reduced tensile notch-sensitivity in pseudo-ductile Thin Ply composites
2018Co-Authors: Michael R Wisnom, Jonathan D Fuller, Mohammad Fotouhi, Gergely Czel, Meisam Jalalvand, Tamas RevAbstract:Pseudo-ductile Thin-Ply composites loaded in tension exhibit a non-linear stress-strain response with a plateau, analogous to yielding in a metal. This provides an alternative means for load redistribution at stress concentrations, giving reduced notch-sensitivity. The notched tensile response of both Thin-Ply hybrid and angle-Ply laminates is presented, and the failure mechanisms described and compared with those of conventional composites to explain the reduced notch sensitivity.
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pseudo ductility of unidirectional Thin Ply hybrid composites in longitudinal compression
Proceedings of the American Society for Composites — Thirty-third Technical Conference, 2018Co-Authors: Putu Suwarta, Gergely Czel, Mohamad Fotouhi, Jakub Rycerz, Mchael R WisnomAbstract:The compression response of unidirectional Thin-Ply carbon (C) standard thickness S-glass (SG) hybrid composites is presented. Gradual failure up to high strain has been demonstrated for [SG1/(C1/SG1)17] and [SG1/(C2/SG1)17] hybrid configurations. The favourable pseudo-ductile behaviour is due to progressive fragmentation and dispersed delamination of the Thin Ply carbon/epoxy layers. For the [SG1/(C3/SG1)17] configuration, sudden failure occurs at a lower strain, but still higher than the compression failure strain of the carbon fibres calculated from the manufacturer’s data sheet. The energy release rate concept can be used to qualitatively explain the behaviour of the different thickness hybrid laminates under compression.
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pseudo ductility and reduced notch sensitivity in multi directional all carbon epoxy Thin Ply hybrid composites
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Gergely Czel, Marco L Longana, Mohammad Fotouhi, Meisam Jalalvand, Tamas Rev, Oliver J Nixonpearson, Michael R WisnomAbstract:Un-notched and notched tensile response and damage accumulation of quasi-isotropic carbon/epoxy hybrid laminates made of ultra-high modulus and intermediate modulus carbon fibre/epoxy Thin-Ply prepregs were studied. It was confirmed that the Ply fragmentation demonstrated previously in unidirectional hybrids as a successful pseudo-ductility mechanism can be transferred to multi-directional laminates. Furthermore, reduced notch sensitivity was demonstrated in quasi-isotropic specimens for both open holes and sharp notches as a result of local Ply fragmentation around the notch.
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Hybrid effects in Thin Ply carbon/glass unidirectional laminates: Accurate experimental determination and prediction
Composites Part A-applied Science and Manufacturing, 2016Co-Authors: Michael R Wisnom, Gergely Czel, Yentl Swolfs, Meisam Jalalvand, Larissa Gorbatikh, Ignace VerpoestAbstract:Experimental results are presented which allow the hybrid effect to be evaluated accurately for Thin Ply carbon/epoxy–glass/epoxy interlayer hybrid composites. It is shown that there is an enhancement in strain at failure of up to 20% for very Thin plies, but no significant effect for thicker plies. Hybrid specimens with thick carbon plies can therefore be used to measure the reference carbon/epoxy failure strain. The latter is significantly higher than the strain from all-carbon specimens in which there is an effect due to stress concentrations at the load introduction. Models are presented which illustrate the mechanisms responsible for the hybrid effect due to the constraint on failure at both the fibre and Ply level. These results give a good understanding of how variability in the carbon fibre strengths can translate into hybrid effects in composite laminates.
Tomohiro Yokozeki - One of the best experts on this subject based on the ideXlab platform.
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gas permeability of cfrp cross Ply laminates with Thin Ply barrier layers under cryogenic and biaxial loading conditions
Composite Structures, 2020Co-Authors: Hitoshi Hamori, Ryo Higuchi, Hisashi Kumazawa, Tomohiro YokozekiAbstract:Abstract Utilization of carbon fiber reinforced plastic (CFRP) composite materials in propellant tanks is expected to drastically reduce the structural weight of space vehicles. However, fuel leakage through the chain of matrix cracks caused by serious thermal residual stress is a considerable problem. To avoid fuel leakage, this study proposes leak barrier layers consisting of Thin-Ply prepregs. Biaxial tensile tests are performed for specimens with or without Thin-Ply barrier layers at cryogenic temperature, and the gas leakage properties of damaged CFRP cross-Ply laminates are investigated. In addition, the formation of leakage paths at cryogenic temperature is simulated by the finite element method based on the experimental data. Finally, the experimental and numerical results demonstrate that Thin-Ply barrier layers increase the tolerance against damage and leakage.
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Damage characterization in Thin-Ply composite laminates under out-of-plane transverse loadings
Composite Structures, 2010Co-Authors: Tomohiro Yokozeki, Akiko Kuroda, Akinori Yoshimura, Toshio Ogasawara, Takahira AokiAbstract:Composite laminates with Thin-Ply layers are expected to exhibit superior damage resistance to the standard composite laminates. This study investigated the damage characteristics of carbon fiber/toughened epoxy Thin-Ply laminates subjected to transverse loadings. Quasi-isotropic laminates were prepared using both standard prepregs and Thin-Ply prepregs in order to examine the effect of Ply thickness on the damage accumulation processes. Clear difference on damage accumulation process between standard laminates and Thin-Ply laminates was identified; fiber fractures were susceptible to formation in Thin-Ply laminates. Finally, the reason of the difference on damage process was investigated using finite element analyses, and it was clarified that the accumulated delamination position has a significant effect on the fiber fractures during the indentation.
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experimental characterization of strength and damage resistance properties of Thin Ply carbon fiber toughened epoxy laminates
Composite Structures, 2008Co-Authors: Tomohiro Yokozeki, Yuichiro Aoki, Toshio OgasawaraAbstract:Composite laminates manufactured from Thin-Ply prepregs are expected to have superior damage resistance properties compared to those from standard prepregs. Although the use of Thin-Ply prepregs leads to increase in manufacturing cost, the damage resistance properties against matrix cracking and delamination increase. This study investigates several strength properties as well as the damage resistance properties of carbon fiber/toughened epoxy composite laminates for the applicability of Thin-Ply prepregs to aircraft structures. Specifically, compressive strengths of open hole laminates (OHC strength) and laminates after impact loadings (CAI strength) are investigated by the comparison of results between laminates manufactured from the Thin-Ply prepregs and the standard prepregs. It is shown that laminates using Thin-Ply prepregs have superior strength compared to those using standard prepregs. It is expected that the design limit of composite aircraft structures increase by using Thin-Ply prepregs.
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Experimental characterization of strength and damage resistance properties of Thin-Ply carbon fiber/toughened epoxy laminates
Composite Structures, 2008Co-Authors: Tomohiro Yokozeki, Yuichiro Aoki, Toshio OgasawaraAbstract:Composite laminates manufactured from Thin-Ply prepregs are expected to have superior damage resistance properties compared to those from standard prepregs. Although the use of Thin-Ply prepregs leads to increase in manufacturing cost, the damage resistance properties against matrix cracking and delamination increase. This study investigates several strength properties as well as the damage resistance properties of carbon fiber/toughened epoxy composite laminates for the applicability of Thin-Ply prepregs to aircraft structures. Specifically, compressive strengths of open hole laminates (OHC strength) and laminates after impact loadings (CAI strength) are investigated by the comparison of results between laminates manufactured from the Thin-Ply prepregs and the standard prepregs. It is shown that laminates using Thin-Ply prepregs have superior strength compared to those using standard prepregs. It is expected that the design limit of composite aircraft structures increase by using Thin-Ply prepregs.
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Experimental and numerical studies of the open-hole compressive strength of Thin-Ply CFRP laminates
Composites Part A: Applied Science and Manufacturing, 1Co-Authors: Kota Takamoto, Toshio Ogasawara, Hiroki Kodama, Tomoisa Mikami, Sota Oshima, Kazuyuki Aoki, Ryo Higuchi, Tomohiro YokozekiAbstract:Abstract Thin prepregs with thickness of less than 0.06 mm support flexible lamination design because it is possible to apPly various stacking sequences. The objective of this study is to elucidate the effects of the layer thickness and stacking sequence on the open-hole compressive (OHC) strength for Thin-Ply carbon fiber reinforced plastic composite (CFRP) laminates. Details of layer thickness and stacking sequence effects on the OHC strength for the Thin-Ply CFRP laminates were evaluated experimentally. Furthermore, finite element analyses incorporating Hashin’s 2-D failure criteria and a cohesive zone model were conducted to evaluate the damage progression behavior. Results demonstrated that the numerical model was useful for predicting the OHC strength of Thin-Ply CFRP laminates with various stacking sequences.
Toshio Ogasawara - One of the best experts on this subject based on the ideXlab platform.
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Damage characterization in Thin-Ply composite laminates under out-of-plane transverse loadings
Composite Structures, 2010Co-Authors: Tomohiro Yokozeki, Akiko Kuroda, Akinori Yoshimura, Toshio Ogasawara, Takahira AokiAbstract:Composite laminates with Thin-Ply layers are expected to exhibit superior damage resistance to the standard composite laminates. This study investigated the damage characteristics of carbon fiber/toughened epoxy Thin-Ply laminates subjected to transverse loadings. Quasi-isotropic laminates were prepared using both standard prepregs and Thin-Ply prepregs in order to examine the effect of Ply thickness on the damage accumulation processes. Clear difference on damage accumulation process between standard laminates and Thin-Ply laminates was identified; fiber fractures were susceptible to formation in Thin-Ply laminates. Finally, the reason of the difference on damage process was investigated using finite element analyses, and it was clarified that the accumulated delamination position has a significant effect on the fiber fractures during the indentation.
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experimental characterization of strength and damage resistance properties of Thin Ply carbon fiber toughened epoxy laminates
Composite Structures, 2008Co-Authors: Tomohiro Yokozeki, Yuichiro Aoki, Toshio OgasawaraAbstract:Composite laminates manufactured from Thin-Ply prepregs are expected to have superior damage resistance properties compared to those from standard prepregs. Although the use of Thin-Ply prepregs leads to increase in manufacturing cost, the damage resistance properties against matrix cracking and delamination increase. This study investigates several strength properties as well as the damage resistance properties of carbon fiber/toughened epoxy composite laminates for the applicability of Thin-Ply prepregs to aircraft structures. Specifically, compressive strengths of open hole laminates (OHC strength) and laminates after impact loadings (CAI strength) are investigated by the comparison of results between laminates manufactured from the Thin-Ply prepregs and the standard prepregs. It is shown that laminates using Thin-Ply prepregs have superior strength compared to those using standard prepregs. It is expected that the design limit of composite aircraft structures increase by using Thin-Ply prepregs.
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Experimental characterization of strength and damage resistance properties of Thin-Ply carbon fiber/toughened epoxy laminates
Composite Structures, 2008Co-Authors: Tomohiro Yokozeki, Yuichiro Aoki, Toshio OgasawaraAbstract:Composite laminates manufactured from Thin-Ply prepregs are expected to have superior damage resistance properties compared to those from standard prepregs. Although the use of Thin-Ply prepregs leads to increase in manufacturing cost, the damage resistance properties against matrix cracking and delamination increase. This study investigates several strength properties as well as the damage resistance properties of carbon fiber/toughened epoxy composite laminates for the applicability of Thin-Ply prepregs to aircraft structures. Specifically, compressive strengths of open hole laminates (OHC strength) and laminates after impact loadings (CAI strength) are investigated by the comparison of results between laminates manufactured from the Thin-Ply prepregs and the standard prepregs. It is shown that laminates using Thin-Ply prepregs have superior strength compared to those using standard prepregs. It is expected that the design limit of composite aircraft structures increase by using Thin-Ply prepregs.
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Experimental and numerical studies of the open-hole compressive strength of Thin-Ply CFRP laminates
Composites Part A: Applied Science and Manufacturing, 1Co-Authors: Kota Takamoto, Toshio Ogasawara, Hiroki Kodama, Tomoisa Mikami, Sota Oshima, Kazuyuki Aoki, Ryo Higuchi, Tomohiro YokozekiAbstract:Abstract Thin prepregs with thickness of less than 0.06 mm support flexible lamination design because it is possible to apPly various stacking sequences. The objective of this study is to elucidate the effects of the layer thickness and stacking sequence on the open-hole compressive (OHC) strength for Thin-Ply carbon fiber reinforced plastic composite (CFRP) laminates. Details of layer thickness and stacking sequence effects on the OHC strength for the Thin-Ply CFRP laminates were evaluated experimentally. Furthermore, finite element analyses incorporating Hashin’s 2-D failure criteria and a cohesive zone model were conducted to evaluate the damage progression behavior. Results demonstrated that the numerical model was useful for predicting the OHC strength of Thin-Ply CFRP laminates with various stacking sequences.
