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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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a novel technique to accurately measure the fibre failure strain in composite laminates under a combined in plane tension and shear stress state
21st International Conference on Composite Materials ICCM 2017, 2017Co-Authors: Meisam Jalalvand, Mohammad Fotouhi, Mun Choong Leong, Michael R WisnomAbstract:A simple and accurate test method is presented to investigate the influence of shear stresses on tensile failure of unidirectional carbon fibre/Epoxy. Glass/carbon hybrid laminates are used to eliminate stress concentrations and avoid premature failure at the end-tabs. Free-edge delamination is suppressed using thin-plies. Angle-ply carbon/Epoxy laminates have been designed to achieve combinations of tensile and shear stresses. It is shown that in-plane shear does not significantly affect the fibre failure strains.
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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.
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design and characterisation of advanced pseudo ductile unidirectional thin ply carbon Epoxy Glass Epoxy hybrid composites
Composite Structures, 2016Co-Authors: Gergely Czel, Meisam Jalalvand, Michael R WisnomAbstract:Abstract A comprehensive set of thin-ply pseudo-ductile unidirectional interlayer hybrid composite materials comprising S-Glass and a variety of thin carbon prepregs was designed and characterised. Unique elastic–yielding–hardening type stress–strain responses similar to those of ductile metals were achieved through fragmentation and stable pull-out of the carbon layers, generating a range of initial moduli, pseudo-yield strains, plateau stresses and pseudo ductile strains for the various configurations. The typical failure modes of thin-ply hybrid composites were highlighted in four series of stress–strain graphs obtained for the same materials with different carbon layer thicknesses. The predicted failure modes agreed well with the experimental results and demonstrated the merit of our two step design framework based on (i) simple analytical criteria and (ii) novel damage mode maps.
De-yi Wang - One of the best experts on this subject based on the ideXlab platform.
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combined effects of ammonium polyphosphate and talc on the fire and mechanical properties of Epoxy Glass fabric composites
Composites Part B-engineering, 2017Co-Authors: Mohammad Rajaei, De-yi Wang, Debes BhattacharyyaAbstract:Abstract The combined effects of ammonium polyphosphate and talc on the fire and mechanical behaviour of Epoxy/Glass fabric composite systems and neat Epoxy resin were investigated. Recorded data from cone calorimeter and UL-94 vertical burning experiments reveal that the incorporation of additives can enhance the flame retardancy of both Epoxy resin and Glass fabric reinforced composites. TGA results demonstrate that the introduction of additives improve the thermal stability of Epoxy resin at high temperatures. Moreover, the addition of flame retardants to Epoxy resin increases the tensile and flexural moduli. However, due to the incompatibility of the additives with Epoxy, the strengths are compromised. Then again, the Epoxy/Glass fabric composites with flame retardant additives have improved the fire properties without significantly affecting the mechanical performance.
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Influence of phenylphosphonate based flame retardant on Epoxy/Glass fiber reinforced composites (GRE): Flammability, mechanical and thermal stability properties
'Elsevier BV', 2017Co-Authors: Zhao Xiaomin, Yang Lingwei, Hueto Martín Francisco, Zhang Xiu-qin, Wang Rui, De-yi WangAbstract:In this work, flame-retardant Glass fiber reinforced Epoxy composites (FGRE) were successfully prepared via adding a novel phenylphosphonate-based flame retardant, N, N'-diamyl-p-phenylphosphonicdiamide (P-MA) into GRE. FGRE12 showed high LOI value of 33%. Meanwhile, FGRE12 passed V-0 rating in UL 94 test and the peak of heating release rate (pHRR) decreased by 54% in comparison with that of GRE. The flame-retardant efficiency of P-MA in GRE was compared with that in Epoxy matrix (EP). Moreover, the influences of P-MA on mechanical and thermal stability properties of GRE were studied systemically. Dynamic mechanical analysis (DMA) studied the influence of P-MA on viscoelasticity of GRE. Fiber push-in test and three-point-bending test were used to evaluate the influence of P-MA on the EP matrix/fiber interface strength and interlamilnar shear strength, respectively. In addition, nanoindentation test was used to study the hardness and Young's modulus of EP matrix. The above results showed that the addition of P-MA did not affect the hardness of Epoxy matrix and interfacial strength (Epoxy matrix/Glass fiber). The influence of P-MA on thermal stability of GRE was studied by thermalgravimetric analysis (TGA). These results would be very important in designing new generation multifunctional Epoxy-based composite materials
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influence of phenylphosphonate based flame retardant on Epoxy Glass fiber reinforced composites gre flammability mechanical and thermal stability properties
Composites Part B-engineering, 2017Co-Authors: Xiaomin Zhao, L W Yang, Francisco Hueto Martin, Xiuqin Zhang, Rui Wang, De-yi WangAbstract:In this work, flame-retardant Glass fiber reinforced Epoxy composites (FGRE) were successfully prepared via adding a novel phenylphosphonate-based flame retardant, N, N'-diamyl-p-phenylphosphonicdiamide (P-MA) into GRE. FGRE12 showed high LOI value of 33%. Meanwhile, FGRE12 passed V-0 rating in UL 94 test and the peak of heating release rate (pHRR) decreased by 54% in comparison with that of GRE. The flame-retardant efficiency of P-MA in GRE was compared with that in Epoxy matrix (EP). Moreover, the influences of P-MA on mechanical and thermal stability properties of GRE were studied systemically. Dynamic mechanical analysis (DMA) studied the influence of P-MA on viscoelasticity of GRE. Fiber push-in test and three-point-bending test were used to evaluate the influence of P-MA on the EP matrix/fiber interface strength and interlamilnar shear strength, respectively. In addition, nanoindentation test was used to study the hardness and Young's modulus of EP matrix. The above results showed that the addition of P-MA did not affect the hardness of Epoxy matrix and interfacial strength (Epoxy matrix/Glass fiber). The influence of P-MA on thermal stability of GRE was studied by thermalgravimetric analysis (TGA). These results would be very important in designing new generation multifunctional Epoxy-based composite materials.
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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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.
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design and characterisation of advanced pseudo ductile unidirectional thin ply carbon Epoxy Glass Epoxy hybrid composites
Composite Structures, 2016Co-Authors: Gergely Czel, Meisam Jalalvand, Michael R WisnomAbstract:Abstract A comprehensive set of thin-ply pseudo-ductile unidirectional interlayer hybrid composite materials comprising S-Glass and a variety of thin carbon prepregs was designed and characterised. Unique elastic–yielding–hardening type stress–strain responses similar to those of ductile metals were achieved through fragmentation and stable pull-out of the carbon layers, generating a range of initial moduli, pseudo-yield strains, plateau stresses and pseudo ductile strains for the various configurations. The typical failure modes of thin-ply hybrid composites were highlighted in four series of stress–strain graphs obtained for the same materials with different carbon layer thicknesses. The predicted failure modes agreed well with the experimental results and demonstrated the merit of our two step design framework based on (i) simple analytical criteria and (ii) novel damage mode maps.
Meisam Jalalvand - One of the best experts on this subject based on the ideXlab platform.
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a novel technique to accurately measure the fibre failure strain in composite laminates under a combined in plane tension and shear stress state
21st International Conference on Composite Materials ICCM 2017, 2017Co-Authors: Meisam Jalalvand, Mohammad Fotouhi, Mun Choong Leong, Michael R WisnomAbstract:A simple and accurate test method is presented to investigate the influence of shear stresses on tensile failure of unidirectional carbon fibre/Epoxy. Glass/carbon hybrid laminates are used to eliminate stress concentrations and avoid premature failure at the end-tabs. Free-edge delamination is suppressed using thin-plies. Angle-ply carbon/Epoxy laminates have been designed to achieve combinations of tensile and shear stresses. It is shown that in-plane shear does not significantly affect the fibre failure strains.
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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.
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design and characterisation of advanced pseudo ductile unidirectional thin ply carbon Epoxy Glass Epoxy hybrid composites
Composite Structures, 2016Co-Authors: Gergely Czel, Meisam Jalalvand, Michael R WisnomAbstract:Abstract A comprehensive set of thin-ply pseudo-ductile unidirectional interlayer hybrid composite materials comprising S-Glass and a variety of thin carbon prepregs was designed and characterised. Unique elastic–yielding–hardening type stress–strain responses similar to those of ductile metals were achieved through fragmentation and stable pull-out of the carbon layers, generating a range of initial moduli, pseudo-yield strains, plateau stresses and pseudo ductile strains for the various configurations. The typical failure modes of thin-ply hybrid composites were highlighted in four series of stress–strain graphs obtained for the same materials with different carbon layer thicknesses. The predicted failure modes agreed well with the experimental results and demonstrated the merit of our two step design framework based on (i) simple analytical criteria and (ii) novel damage mode maps.
Xiaomin Zhao - One of the best experts on this subject based on the ideXlab platform.
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influence of phenylphosphonate based flame retardant on Epoxy Glass fiber reinforced composites gre flammability mechanical and thermal stability properties
Composites Part B-engineering, 2017Co-Authors: Xiaomin Zhao, L W Yang, Francisco Hueto Martin, Xiuqin Zhang, Rui Wang, De-yi WangAbstract:In this work, flame-retardant Glass fiber reinforced Epoxy composites (FGRE) were successfully prepared via adding a novel phenylphosphonate-based flame retardant, N, N'-diamyl-p-phenylphosphonicdiamide (P-MA) into GRE. FGRE12 showed high LOI value of 33%. Meanwhile, FGRE12 passed V-0 rating in UL 94 test and the peak of heating release rate (pHRR) decreased by 54% in comparison with that of GRE. The flame-retardant efficiency of P-MA in GRE was compared with that in Epoxy matrix (EP). Moreover, the influences of P-MA on mechanical and thermal stability properties of GRE were studied systemically. Dynamic mechanical analysis (DMA) studied the influence of P-MA on viscoelasticity of GRE. Fiber push-in test and three-point-bending test were used to evaluate the influence of P-MA on the EP matrix/fiber interface strength and interlamilnar shear strength, respectively. In addition, nanoindentation test was used to study the hardness and Young's modulus of EP matrix. The above results showed that the addition of P-MA did not affect the hardness of Epoxy matrix and interfacial strength (Epoxy matrix/Glass fiber). The influence of P-MA on thermal stability of GRE was studied by thermalgravimetric analysis (TGA). These results would be very important in designing new generation multifunctional Epoxy-based composite materials.