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Zuoguang Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of mwcnts added by electrostatic flocking method on adhesion of carbon fiber prepreg nomex honeycomb sandwich composites
Materials & Design, 2017Co-Authors: Chao Chen, Yanxia Li, Yizhuo Gu, Min Li, Zuoguang ZhangAbstract:Abstract To improve the adhesion of face sheet and core in sandwich composites, multi-walled carbon nanotubes (MWCNTs) were added by the electrostatic flocking method to reinforce the adhesive fillet. MWCNTs on surface and sub-surface of face sheet were taken into account to analyze the effect of adding locations of MWCNTs. The sandwich composites with different weight contents of MWCNTs were prepared by Autoclave Process. The size of adhesive fillet confirmed that the electrostatic flocking method could ensure the forming quality of sandwich composites with self-adhesive prepreg skin. Climbing drum peel test and flexural test were adopted for mechanical assessment. The results showed that the Process of MWCNTs on sub-surface demonstrated a remarkable enhancement of both the peel properties and flexural properties for samples with 1.5 wt% MWCNTs in comparison to the samples of pure prepreg. The reinforcing mechanism was analyzed by the microstructures of adhesive fillet and it is found that the different enhancement effect was attributed to the distribution features of MWCNTs in the adhesive fillet.
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Radiation shielding property of structural polymer composite: Continuous basalt fiber reinforced epoxy matrix composite containing erbium oxide
Composites Science and Technology, 2017Co-Authors: Ran Li, Zhongjia Yang, Gaolong Zhang, Yizhuo Gu, Min Li, Zuoguang ZhangAbstract:For protecting human body and equipment against radiation in nuclear power industry, radiation medicine and aerospace exploration, advanced materials possessing good shielding capability, low density and high mechanical strength and modulus are in urgent demand. In this study, radiation protective basalt fiber (BF) reinforced epoxy matrix composite containing erbium oxide (Er 2 O 3 ) particles was fabricated by prepreg-Autoclave Process, in order to make a novel mechanical/radiation shielding composite. For prepared unidirectional and quasi-isotropic BF/Er 2 O 3 composite laminates, basalt fibers and Er 2 O 3 particles distributed uniformly, and no obvious agglomeration of particles and defects were found. NaI(Tl) detector was used to test mass attenuation coefficient for evaluating X and gamma rays shielding performance at different photon energies ranging from 31 keV to 662 keV. The experimental results indicate that BF/Er 2 O 3 composite shows good X and gamma rays shielding performance, and mass attenuation coefficient of BF/Er 2 O 3 composite is much larger than that of aluminum in relatively low energy from 31 keV to 80 keV. The effect of prepreg stacking consequence on shielding performance was also discussed. In addition, to verify the applicability of classic “mixture role” on mass attenuation coefficient of anisotropic composites, theoretical mass attenuation coefficient at different photon energies was calculated using XCOM software based on the weight fraction and mass attenuation coefficient of each constituent element among BF/Er 2 O 3 composite. It is found that there is maximum deviation of 10.3% between experimental and theoretical results. Thus, it is believed that the method is suitable for predicting shielding performance of continuous fiber reinforced composite materials. Considering the advantages in light weight and high mechanical property, the studied three-phase composite is promising for using in radiation shielding structure application.
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manufacture and characterization of carbon fiber composite stiffened skin by resin film infusion prepreg co curing Process
Journal of Reinforced Plastics and Composites, 2014Co-Authors: Zhongjia Yang, Dongmei Zhang, Lijie Jia, Zuoguang ZhangAbstract:I-shaped stiffened skin was manufactured by a new co-cured resin film infusion Process (co-RFI) with fiber preform stiffener and prepreg skin. One kind of epoxy resin film and four kinds of carbon fiber prepreg were used. Resin flow behavior, Processing quality, and mechanical performance were investigated for co-RFI stiffened skin. Sole prepreg/Autoclave Process and resin film infusion Process were also adopted for comparison. Resin flow front and resin pressure were detected by self-developed monitoring systems. Optical micrographs and thickness measurement were employed to evaluate Processing quality. Moreover, pull-off test was used to analyze the influences of core filler and prepreg systems in skin on the mechanical performance of stiffened skin. The results show that with reasonable Processing conditions, good Processing quality, and mechanical property at co-curing interface region can be achieved for co-RFI stiffened skin. Co-RFI Process is suitable to fabricate composite structure with high flex...
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co curing Process combining resin film infusion with prepreg and co cured interlaminar properties of carbon fiber composites
Journal of Composite Materials, 2014Co-Authors: Dongmei Zhang, Zuoguang ZhangAbstract:In this article, the carbon fiber/epoxy resin matrix composite laminates were fabricated using a co-curing Process combining resin film infusion (RFI) Process with prepreg-Autoclave Process, called co-resin film infusion. A kind of unidirectional prepreg and its corresponding resin film were adopted. The compaction and defects of laminates cured by different Processing were studied. Mode I and mode II interlaminar fracture toughness were adopted to evaluate the co-cured interlaminar properties of the co-curing laminates and were compared with those of laminates Processed by the prepreg-Autoclave Process and the resin film infusion Process. Moreover, the effects of lay-up type of prepreg part and resin film infusion part, isothermal dwell and epoxy tackifier of fiber preform were also studied. The results show that these factors have important effects on the Processing qualities of the laminates cured by co-curing Process, including resin-rich regions and voids, resulting in different interlaminar fracture...
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role of tool part interaction in consolidation of l shaped laminates during Autoclave Process
Applied Composite Materials, 2012Co-Authors: Jing Sun, Zuoguang ZhangAbstract:The role of tool-part interaction in the consolidation Process of the L-shaped laminate was studied using a finite element model. The tool-part shear actions during Processing were modeled by introducing shear layers. The predicted data demonstrate the necessity of considering the slippage between the tools and the laminate in simulations. A parametric study examining the effects of the shear layer properties on the compacting behavior was performed and the results show that improving the slippage ability of the male mold upon the composite part is of advantage to apply the pressure on the corner section of the L-shaped laminate. Moreover, the mechanical properties and the thickness of the shear layer have a significant influence on the modeling of the consolidation Process.
C.m. Manjunatha - One of the best experts on this subject based on the ideXlab platform.
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effect of hygrothermal aging on the interlaminar shear strength of a carbon fibre composite
Procedia structural integrity, 2019Co-Authors: Kishora Shetty, C.m. Manjunatha, Shylaja SrihariAbstract:Abstract Carbon Fibre Reinforced Plastic (CFRP) composites are used many applications in aerospace structures due to their high specific strength and stiffness. Composite aircraft structures are usually exposed to a range of environmental conditions such as hygrothermal, UV radiation, chemical environments, biological condition etc., in their service life and may degrade. Moisture absorption at different hygrothermal conditions and its effects on properties of CFRP composites is a useful parameter to designers and application engineers. In this study, UD carbon fiber/epoxy composite laminates were fabricated (HexPly® M21E/34%/UD/194/IMA) from prepreg using standard Autoclave Process. Inter Laminar Shear Strength (ILSS) test specimens were cut and prepared from theses laminates. Hot-wet specimens were aged at two different conditions; 75 0C/ 85% RH, 55 0C/ 100% RH until attaining moisture absorption saturation. Three-point bend tests were conducted as per ASTM test standard specifications using a 25 KN servo-hydraulic test machine to determine ILSS properties for aged and unaged material. Respective hot-wet conditions were maintained even during the mechanical tests. Tests results show that moisture absorption rate increases gradually and attains saturation at about 1 wt. % under both conditions. Inter laminar shear strength reduced significantly by about 33% due to presence of moisture. Microscopic observation of failed samples also investigated to study the fracture behavior and reported in this paper.
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Prediction of Mode II Delamination Onset Life Under Spectrum Fatigue Loads Using Equivalent Strain Energy Release Rate Concept
Advances in Structural Integrity, 2017Co-Authors: A R Anilchandra, M. Seshagirachari, Ramesh Bojja, Narasimhan Jagannathan, C.m. ManjunathaAbstract:End notched flexure (ENF) test specimens of unidirectional IMA/M21 carbon fiber composite (CFC) were fabricated using standard Autoclave Process. A Teflon insert was used to simulate a delamination at the midplane. Three-point bend setup tests were conducted at an average frequency of 2 Hz using a 25 kN servo-hydraulic test machine in room temperature conditions. Constant amplitude fatigue tests were done at three different stress ratios, viz. R = 0.0, 0.5, and −1.0 to construct the standard G-N onset diagram, similar to S–N curve in its usefulness. N onset was identified as 5% change in initial compliance value. Using an equivalent energy release rate parameter, G eq, all the curves were collapsed into a single curve in the form of Basquin’s equation. The equation was subsequently used in predicting the delamination onset-of-growth life under a standard mini-FALSTAFF spectrum load sequence. A fairly good correlation was found between the predicted and experimental mode II onset-of-growth behavior.
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fatigue life prediction of a unidirectional carbon fiber composite under off axis spectrum loads using 3d constant life diagram
Materials Performance and Characterization, 2016Co-Authors: M S Hussain, Narasimhan Jagannathan, A R Anilchandra, C.m. ManjunathaAbstract:In this study, a novel concept of 3D constant life diagram (CLD) for fatigue life prediction of a unidirectional (UD) polymer composite under spectrum load is proposed. Further, it is constructed and used to predict the fatigue life of a UD carbon fiber composite (CFC) subjected to a standard spectrum load sequence at an arbitrary off-axis angle. First, UD IMA/M21 CFC laminates were fabricated by an Autoclave Process. Static mechanical tests were conducted to determine the tensile and compressive strength at various off-axis angles ranging from 0° to 90°. Then the constant amplitude (CA) fatigue tests at three different stress ratios, R = σmin/σmax of 0.1 (tension-tension), −1.0 (tension-compression), and 10.0 (compression-compression) and at various off-axis angles between 0° and 90° at each of these stress ratios were performed to determine stress-life curves. Using the static and CA fatigue data generated, 3D CLD for UD CFC was constructed. Further, fatigue life of UD CFC subjected to a standard mini-FALSTAFF spectrum load sequence at an arbitrary off-axis angle of 20° was predicted following an empirical method using 3D CLD. Fatigue tests under the mini-FALSTAFF spectrum load sequence at an off-axis angle of 20° were also conducted at various reference stresses and compared with the predictions. A reasonably good correlation was observed between the predicted and experimental fatigue lives under off-axis spectrum loads.
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Onset-of-growth behavior of mode II delamination in a carbon fiber composite under spectrum fatigue loads
Composite Structures, 2015Co-Authors: Narasimhan Jagannathan, A.r. Anil Chandra, C.m. ManjunathaAbstract:End notched flexure (ENF) test specimens of unidirectional IMA/M21 carbon fiber composite were fabricated using standard Autoclave Process. A teflon insert was used to simulate a delamination at the mid plane. Three point bend tests were conducted under a modified mini-FALSTAFF spectrum load sequence with various reference strain energy release rate, Gref to determine the onset-of-growth of mode II delamination. The onset life was identified as 5% increase in compliance during the fatigue test. Onset fatigue life was observed to increase with decreasing, Gref. Further, the onset-of-growth was predicted using empirical models. For this purpose, the mode II fracture toughness, GIIc and the constant amplitude fatigue data, Gmax–Nonset curves at two different stress ratios were determined and used to construct a constant onset life diagram (COLD). Following the general procedure of damage estimation, the onset-of-growth was predicted using the COLD and compared with experimental results.
S V Hoa - One of the best experts on this subject based on the ideXlab platform.
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mechanical properties of carbon fiber reinforced epoxy clay nanocomposites
Composites Science and Technology, 2008Co-Authors: S V HoaAbstract:Epoxy/clay nanocomposites (ENCs) were fabricated from TGDDM epoxy and montmorillonite nanoclay. Carbon fiber reinforced epoxy/clay nanocomposites (CFRENCs) were manufactured through hot melt lay-up plus Autoclave Process. The CFRENCs have uniform fiber volume fraction, very few dry spots, and very few resin rich areas. The interlaminar fracture toughness of CFRENCs was increased by 85% with the introduction of 4 phr nanoclay in epoxy. Small amount of nanoclay (2 phr) added into the epoxy of carbon/epoxy composites can enhance the flexural strength by 38%.
Daining Fang - One of the best experts on this subject based on the ideXlab platform.
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effect of manufacturing defect on mechanical performance of plain weave carbon epoxy composite based on 3d geometrical reconstruction
Composite Structures, 2018Co-Authors: Panding Wang, Haosen Chen, C. S. Wang, Daining FangAbstract:Abstract The investigation on the effect of manufacturing defect on the mechanical performance of composite is essential for the design and application in practice. In this study, the plain weave carbon fiber reinforced polymer (CFRP) laminates are fabricated by the Autoclave Process and vacuum bag Process (VBP), respectively. Uniaxial tensile testes are conducted with a digital image correlation (DIC) system to obtain the macroscopic mechanical performance and local strain distribution. The internal microdefects of composite laminates are captured by micron-resolution computed tomography (μCT) detection technique, including the size and distribution of void, total volume fraction and geometrical parameters of yarns. Based on the Texgen software and Monte-Carlo algorithm, virtual samples with various void contents are constructed to evaluate the impact of defect using finite element solver ABAQUS/Standard. To substantiate this work, we present a comparative study considering both Autoclave and VBP. The effect of void defect on the mechanical performances of CFRP laminate is analyzed through finite element method (FEM). The results reveal that the effect of void defect on the surface strain distribution of laminate is significant, especially the value of maximum strain, which will increase obviously with the void defect content. In addition, the overall stiffness predicted by numerical simulation, taking the effect of void defect into account, is lower than that of theoretical.
Narasimhan Jagannathan - One of the best experts on this subject based on the ideXlab platform.
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Prediction of Mode II Delamination Onset Life Under Spectrum Fatigue Loads Using Equivalent Strain Energy Release Rate Concept
Advances in Structural Integrity, 2017Co-Authors: A R Anilchandra, M. Seshagirachari, Ramesh Bojja, Narasimhan Jagannathan, C.m. ManjunathaAbstract:End notched flexure (ENF) test specimens of unidirectional IMA/M21 carbon fiber composite (CFC) were fabricated using standard Autoclave Process. A Teflon insert was used to simulate a delamination at the midplane. Three-point bend setup tests were conducted at an average frequency of 2 Hz using a 25 kN servo-hydraulic test machine in room temperature conditions. Constant amplitude fatigue tests were done at three different stress ratios, viz. R = 0.0, 0.5, and −1.0 to construct the standard G-N onset diagram, similar to S–N curve in its usefulness. N onset was identified as 5% change in initial compliance value. Using an equivalent energy release rate parameter, G eq, all the curves were collapsed into a single curve in the form of Basquin’s equation. The equation was subsequently used in predicting the delamination onset-of-growth life under a standard mini-FALSTAFF spectrum load sequence. A fairly good correlation was found between the predicted and experimental mode II onset-of-growth behavior.
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fatigue life prediction of a unidirectional carbon fiber composite under off axis spectrum loads using 3d constant life diagram
Materials Performance and Characterization, 2016Co-Authors: M S Hussain, Narasimhan Jagannathan, A R Anilchandra, C.m. ManjunathaAbstract:In this study, a novel concept of 3D constant life diagram (CLD) for fatigue life prediction of a unidirectional (UD) polymer composite under spectrum load is proposed. Further, it is constructed and used to predict the fatigue life of a UD carbon fiber composite (CFC) subjected to a standard spectrum load sequence at an arbitrary off-axis angle. First, UD IMA/M21 CFC laminates were fabricated by an Autoclave Process. Static mechanical tests were conducted to determine the tensile and compressive strength at various off-axis angles ranging from 0° to 90°. Then the constant amplitude (CA) fatigue tests at three different stress ratios, R = σmin/σmax of 0.1 (tension-tension), −1.0 (tension-compression), and 10.0 (compression-compression) and at various off-axis angles between 0° and 90° at each of these stress ratios were performed to determine stress-life curves. Using the static and CA fatigue data generated, 3D CLD for UD CFC was constructed. Further, fatigue life of UD CFC subjected to a standard mini-FALSTAFF spectrum load sequence at an arbitrary off-axis angle of 20° was predicted following an empirical method using 3D CLD. Fatigue tests under the mini-FALSTAFF spectrum load sequence at an off-axis angle of 20° were also conducted at various reference stresses and compared with the predictions. A reasonably good correlation was observed between the predicted and experimental fatigue lives under off-axis spectrum loads.
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Onset-of-growth behavior of mode II delamination in a carbon fiber composite under spectrum fatigue loads
Composite Structures, 2015Co-Authors: Narasimhan Jagannathan, A.r. Anil Chandra, C.m. ManjunathaAbstract:End notched flexure (ENF) test specimens of unidirectional IMA/M21 carbon fiber composite were fabricated using standard Autoclave Process. A teflon insert was used to simulate a delamination at the mid plane. Three point bend tests were conducted under a modified mini-FALSTAFF spectrum load sequence with various reference strain energy release rate, Gref to determine the onset-of-growth of mode II delamination. The onset life was identified as 5% increase in compliance during the fatigue test. Onset fatigue life was observed to increase with decreasing, Gref. Further, the onset-of-growth was predicted using empirical models. For this purpose, the mode II fracture toughness, GIIc and the constant amplitude fatigue data, Gmax–Nonset curves at two different stress ratios were determined and used to construct a constant onset life diagram (COLD). Following the general procedure of damage estimation, the onset-of-growth was predicted using the COLD and compared with experimental results.
