The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Amar Patnaik - One of the best experts on this subject based on the ideXlab platform.
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viscoelastic interpretations of erosion performance of short aramid fibre reinforced vinyl ester resin composites
Journal of Materials Science, 2011Co-Authors: Sandeep Kumar, Bhabani K Satapathy, Amar PatnaikAbstract:Short aramid fibre reinforced vinyl ester resin based isotropic composites are fabricated with varying fibre weight fractions (20–50 wt%). The composites were evaluated for their erosion performance under a dynamic set of variables such as impingement angle (30°–90°), impact velocity (43–76 m/s), erodent size (250–600 μm) and stand-off distance (55–85 mm) following design of experiments (DOE) based on Taguchi analysis approach. The thermo-mechanical attributes such as storage modulus, loss modulus and damping properties as viscoelastic responses of the composites were investigated in the temperature range of 0–180 °C for their possible interpretations regarding Reinforcement Efficiency and energy dissipation aspects relevant to erosion process. An interrelation between the full-width half-maxima (FWHM) of loss modulus peak and erosion rate has emerged indicating the erosion to be mainly controlled by the fibre–matrix interfacial characteristics. The eroded surface morphology investigation by scanning electron microscopy (SEM) revealed the nature of wear-craters, material damage mode and other qualitative attributes responsible in facilitating erosion of the composites.
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thermo mechanical correlations to erosion performance of short carbon fibre reinforced vinyl ester resin composites
Materials & Design, 2011Co-Authors: Sandeep Kumar, Bhabani K Satapathy, Amar PatnaikAbstract:Abstract Thermo-mechanical properties and erosion performance of short carbon fibre reinforced vinyl ester resin based isotropic polymer composites with four different fibre weight fractions have been investigated. The storage, loss and damping characteristics were analysed to assess the energy absorption/viscous recoverable energy dissipation and Reinforcement Efficiency of the composites as a function of fibre content in the temperature range of 0–140 °C. The composite with 30 wt.% of short carbon fibres has been observed to exhibit superior thermo-mechanical response with highest energy dissipation/damping ability accompanied with a constant storage modulus without any substantial decay till 60 °C. The erosion rates (Er) of these composites are evaluated at different impingement angles (30–90°), fibre loadings (20–50 wt.%), impact velocities (43–76 m/s), stand-off distances (55–85 mm) and erodent sizes (250–600 μm) following the erosion test schedule in an air jet type test rig. An optimal parameter combination is determined and subsequently validated for erosion rate minimization following Taguchi method and by conducting confirmation experiments. A correlation between the loss-modulus inverse and the erosion rate has been observed which conceptually establishes a possible mechanistic equivalence between erosion and dynamic mechanical loading modes. The morphologies of eroded surface are examined by the scanning electron microscopy to investigate the nature of wear-craters, material damage mode and other qualitative attributes responsible for promoting erosion.
Sandeep Kumar - One of the best experts on this subject based on the ideXlab platform.
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viscoelastic interpretations of erosion performance of short aramid fibre reinforced vinyl ester resin composites
Journal of Materials Science, 2011Co-Authors: Sandeep Kumar, Bhabani K Satapathy, Amar PatnaikAbstract:Short aramid fibre reinforced vinyl ester resin based isotropic composites are fabricated with varying fibre weight fractions (20–50 wt%). The composites were evaluated for their erosion performance under a dynamic set of variables such as impingement angle (30°–90°), impact velocity (43–76 m/s), erodent size (250–600 μm) and stand-off distance (55–85 mm) following design of experiments (DOE) based on Taguchi analysis approach. The thermo-mechanical attributes such as storage modulus, loss modulus and damping properties as viscoelastic responses of the composites were investigated in the temperature range of 0–180 °C for their possible interpretations regarding Reinforcement Efficiency and energy dissipation aspects relevant to erosion process. An interrelation between the full-width half-maxima (FWHM) of loss modulus peak and erosion rate has emerged indicating the erosion to be mainly controlled by the fibre–matrix interfacial characteristics. The eroded surface morphology investigation by scanning electron microscopy (SEM) revealed the nature of wear-craters, material damage mode and other qualitative attributes responsible in facilitating erosion of the composites.
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thermo mechanical correlations to erosion performance of short carbon fibre reinforced vinyl ester resin composites
Materials & Design, 2011Co-Authors: Sandeep Kumar, Bhabani K Satapathy, Amar PatnaikAbstract:Abstract Thermo-mechanical properties and erosion performance of short carbon fibre reinforced vinyl ester resin based isotropic polymer composites with four different fibre weight fractions have been investigated. The storage, loss and damping characteristics were analysed to assess the energy absorption/viscous recoverable energy dissipation and Reinforcement Efficiency of the composites as a function of fibre content in the temperature range of 0–140 °C. The composite with 30 wt.% of short carbon fibres has been observed to exhibit superior thermo-mechanical response with highest energy dissipation/damping ability accompanied with a constant storage modulus without any substantial decay till 60 °C. The erosion rates (Er) of these composites are evaluated at different impingement angles (30–90°), fibre loadings (20–50 wt.%), impact velocities (43–76 m/s), stand-off distances (55–85 mm) and erodent sizes (250–600 μm) following the erosion test schedule in an air jet type test rig. An optimal parameter combination is determined and subsequently validated for erosion rate minimization following Taguchi method and by conducting confirmation experiments. A correlation between the loss-modulus inverse and the erosion rate has been observed which conceptually establishes a possible mechanistic equivalence between erosion and dynamic mechanical loading modes. The morphologies of eroded surface are examined by the scanning electron microscopy to investigate the nature of wear-craters, material damage mode and other qualitative attributes responsible for promoting erosion.
Bhabani K Satapathy - One of the best experts on this subject based on the ideXlab platform.
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viscoelastic interpretations of erosion performance of short aramid fibre reinforced vinyl ester resin composites
Journal of Materials Science, 2011Co-Authors: Sandeep Kumar, Bhabani K Satapathy, Amar PatnaikAbstract:Short aramid fibre reinforced vinyl ester resin based isotropic composites are fabricated with varying fibre weight fractions (20–50 wt%). The composites were evaluated for their erosion performance under a dynamic set of variables such as impingement angle (30°–90°), impact velocity (43–76 m/s), erodent size (250–600 μm) and stand-off distance (55–85 mm) following design of experiments (DOE) based on Taguchi analysis approach. The thermo-mechanical attributes such as storage modulus, loss modulus and damping properties as viscoelastic responses of the composites were investigated in the temperature range of 0–180 °C for their possible interpretations regarding Reinforcement Efficiency and energy dissipation aspects relevant to erosion process. An interrelation between the full-width half-maxima (FWHM) of loss modulus peak and erosion rate has emerged indicating the erosion to be mainly controlled by the fibre–matrix interfacial characteristics. The eroded surface morphology investigation by scanning electron microscopy (SEM) revealed the nature of wear-craters, material damage mode and other qualitative attributes responsible in facilitating erosion of the composites.
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thermo mechanical correlations to erosion performance of short carbon fibre reinforced vinyl ester resin composites
Materials & Design, 2011Co-Authors: Sandeep Kumar, Bhabani K Satapathy, Amar PatnaikAbstract:Abstract Thermo-mechanical properties and erosion performance of short carbon fibre reinforced vinyl ester resin based isotropic polymer composites with four different fibre weight fractions have been investigated. The storage, loss and damping characteristics were analysed to assess the energy absorption/viscous recoverable energy dissipation and Reinforcement Efficiency of the composites as a function of fibre content in the temperature range of 0–140 °C. The composite with 30 wt.% of short carbon fibres has been observed to exhibit superior thermo-mechanical response with highest energy dissipation/damping ability accompanied with a constant storage modulus without any substantial decay till 60 °C. The erosion rates (Er) of these composites are evaluated at different impingement angles (30–90°), fibre loadings (20–50 wt.%), impact velocities (43–76 m/s), stand-off distances (55–85 mm) and erodent sizes (250–600 μm) following the erosion test schedule in an air jet type test rig. An optimal parameter combination is determined and subsequently validated for erosion rate minimization following Taguchi method and by conducting confirmation experiments. A correlation between the loss-modulus inverse and the erosion rate has been observed which conceptually establishes a possible mechanistic equivalence between erosion and dynamic mechanical loading modes. The morphologies of eroded surface are examined by the scanning electron microscopy to investigate the nature of wear-craters, material damage mode and other qualitative attributes responsible for promoting erosion.
Lars Berglund - One of the best experts on this subject based on the ideXlab platform.
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strong surface treatment effects on Reinforcement Efficiency in biocomposites based on cellulose nanocrystals in poly vinyl acetate matrix
Biomacromolecules, 2015Co-Authors: Farhan Ansari, Michaela Salajkova, Qi Zhou, Lars BerglundAbstract:In this work, the problem to disperse cellulose nanocrystals (CNC) in hydrophobic polymer matrices has been addressed through application of an environmentally friendly chemical modification approach inspired by clay chemistry. The objective is to compare the effects of unmodified CNC and modified CNC (modCNC) Reinforcement, where degree of CNC dispersion is of interest. Hydrophobic functionalization made it possible to disperse wood-based modCNC in organic solvent and cast well-dispersed nanocomposite films of poly(vinyl acetate) (PVAc) with 1-20 wt % CNC. Composite films were studied by infrared spectroscopy (FT-IR), UV-vis spectroscopy, dynamic mechanical thermal analysis (DMTA), tensile testing, and field-emission scanning electron microscopy (FE-SEM). Strongly increased mechanical properties were observed for modCNC nanocomposites. The Reinforcement Efficiency was much lower in unmodified CNC composites, and specific mechanisms causing the differences are discussed.
Satish Kumar - One of the best experts on this subject based on the ideXlab platform.
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Reinforcement Efficiency of carbon nanotubes and their effect on crystal crystal slip in poly ether ketone carbon nanotube composite fibers
Composites Science and Technology, 2017Co-Authors: Bradley A Newcomb, Han Gi Chae, Lindsey Thomson, Jeffrey Luo, Jongbeom Baek, Satish KumarAbstract:Abstract Poly(ether ketone) (PEK)/carbon nanotube (CNT) composite fibers have been produced using dry-jet wet spinning. Carbon nanofibers (CNF), few-walled carbon nanotubes (FWNT), and multi-walled nanotubes (MWNT) have been utilized as nanofillers, with few-walled carbon nanotube loadings as high as 28 wt%. The interfacial strength of the PEK/FWNT and PEK/MWNT fibers were evaluated through the monitoring of the G-mode Raman peak shift as a function of fiber strain. Interfacial shear strengths as high as 14.2 MPa were measured for the PEK/FWNT fiber with 28 wt% CNT loading, a 1320% increase as compared to the PEK/MWNT fiber with 5 wt% loading (1.0 MPa). Tg of the PEK/FWNT fibers increased by 19 °C as the FWNT loading was increased from 5 wt% to 28 wt%. A second peak in the tan δ behavior of all PEK/CNT fibers was also observed. This second tan δ peak (T ∼ 240 °C–250 °C) is attributed to the α*-transition (crystal-crystal slip) in the PEK crystalline regions, and its presence is more pronounced (higher magnitude of tan δ) in all PEK/FWNT fibers as compared to PEK/MWNT and PEK/CNF fibers. FWNTs are restricting the mobility of the amorphous PEK as evidenced by the increasing Tg. Enhanced PEK crystal-crystal slip corresponds to increasing large scale chain mobility in the crystalline regions of the PEK at Tα*. We propose a model which correlates the increase in PEK-FWNT interfacial shear strength to an increase in large scale chain mobility where crystal-crystal slip precedes failure of PEK/CNT interface at Tα* for the PEK/FWNT fibers.
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a comparison of Reinforcement Efficiency of various types of carbon nanotubes in polyacrylonitrile fiber
Polymer, 2005Co-Authors: Han Gi Chae, T V Sreekumar, Tetsuya Uchida, Satish KumarAbstract:Abstract Polyacrylonitrile (PAN)/carbon nanotubes (CNTs) composite fibers were spun from solutions in dimethyl acetamide (DMAc), using single wall (SWNTs), double wall (DWNTs), multi wall (MWNTs) carbon nanotubes, and vapor grown carbon nanofibers (VGCNFs). In each case, CNT content was 5 wt% with respect to the polymer. Structure, morphology, and properties of the composite fibers have been characterized using X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, tensile tests, dynamic mechanical tests, as well as thermal shrinkage. While all nanotubes contributed to property improvements, maximum increase in modulus (75%) and reduction in thermal shrinkage (up to 50%) was observed in the SWNT containing composites, and the maximum improvement in tensile strength (70%), strain to failure (110%), and work of rupture (230%) was observed in the MWNTs containing composites. PAN orientation is higher in the composite fiber (orientation factor up to 0.62) than in the control PAN fiber (orientation factor 0.52), and the PAN crystallite size in the composite fiber is up to 35% larger than in the control PAN (3.7 nm), while the overall PAN crystallinity diminished slightly. Nanotube orientation in the composite fibers is significantly higher (0.98 for SWNTs, 0.88 for DWNTs, and 0.91 for MWNTs and VGCNFs) than the PAN orientation (0.52–0.62). Improvement in low strain properties (modulus and shrinkage) was attributed to PAN interaction with the nanotube, while the improvement in high strain properties (tensile strength, elongation to break, and work of rupture) at least in part is attributed to the nanotube length. Property improvements have been analyzed in terms of nanotube surface area and orientation.
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processing and properties of poly methyl methacrylate carbon nano fiber composites
Composites Part B-engineering, 2004Co-Authors: Jijun Zeng, Bethany Saltysiak, W S Johnson, David A Schiraldi, Satish KumarAbstract:Single wall carbon nanotubes, multi-wall carbon nanotubes, as well as carbon nano fibers (CNF) are being used for reinforcing polymer matrices. In this study, poly(methyl methacrylate) (PMMA) nanocomposites have been processed by melt blending, containing two different grades (PR-21-PS and PR-24-PS) of CNF manufactured by Applied Sciences Inc. The amount of nano fibers used was 5 and 10 wt%, respectively. The PMMA/CNF composites were processed into 4 mm diameter rods and 60 μm diameter fibers using small-scale melt spinning equipment. At 5 wt% CNF, composite rods as well as fibers show over 50% improvement in axial tensile modulus as compared to the control PMMA rod and fibers, respectively. The Reinforcement Efficiency decreased at 10 wt% CNF. The PMMA/CNF nanocomposite fibers also show enhanced thermal stability, significantly reduced shrinkage and enhanced modulus retention with temperature, as well as improved compressive strength. The CNF Reinforcement Efficiency has been analyzed using the modified Cox model.