The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Sheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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effects of gradual Matrix Crack closure on the constitutive behavior of sic sic composites upon unloading
Ceramics International, 2017Co-Authors: Sheng Zhang, Xiguang Gao, Hongnian Dong, Yingdong Song, Shengyang PangAbstract:Abstract Gradual Matrix closure and its effects on the constitutive behavior of SiC/SiC composites are examined in the present study. Real-time Matrix Crack detection and a macroscopic loading–unloading tensile test are performed on SiC/SiC minicomposites. To verify the effects of Matrix Crack closure, stress-strain responses under loading and unloading with and without Crack closure are discussed. The experimental and numerical results show that Matrix Cracks close gradually upon unloading, and gradual Matrix closure greatly reduces the unloading stiffness.
Yanan Yuan - One of the best experts on this subject based on the ideXlab platform.
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caustic investigation of dynamic interactions between propagating Matrix Crack and modified fibre bundles
Polymer Testing, 2018Co-Authors: Yanan Yuan, Xuefeng Yao, Bin LiuAbstract:Abstract The dynamic interactions between a propagating Crack in a Matrix and fibre bundles coated with multi-wall carbon nanotubes (MWCNTs) are investigated. First, the dynamic stress intensity factor at the propagating Crack tip in front of the fibre bundles was derived. Second, dynamic caustic experiments were performed to characterise the dynamic interactions for three different modified fibre/epoxy specimens with MWCNTs. Finally, important fracture parameters of these specimens are evaluated. The modified MWCNT fibre bundles perform better than untreated fibre/epoxy specimens in reducing the dynamic stress intensity factor and the Crack propagation velocity at the propagating Crack tip in front of the fibre bundles. The modified MWCNT-coated fibre bundles can also realise equilibrium partitioning of the fibre fracture energy and interfacial bonding energy, thus preventing massive interfacial debonding and Matrix failure. These results can be used to evaluate the toughening effect of carbon nanotubes on polymer composites.
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photoelastic investigation of interaction between Matrix Crack and different shapes of inclusions
Journal of Testing and Evaluation, 2016Co-Authors: Wenfeng Hao, Can Tang, Yanan YuanAbstract:The interaction between different shapes of inclusions and the mode I Matrix Crack was studied experimentally using the photoelasticity method. First, the stress intensity factor (SIF) at the Matrix Crack tip in the neighborhood of the inclusions was derived based on transformation toughening theory and the Eshelby equivalent inclusion method. Then, photoelastic experiments were conducted using specimens with different shapes of inclusions, and the typical isochromatic fringe patterns around the Crack tip near the inclusions were obtained. Finally, a numerical simulation was conducted for the same problem using ABAQUS, and the stress intensity factors computed from the finite-element method were compared with the experimental results. The results show that the stress intensity factors extracted from isochromatic fringe patterns agree well with the numerical and theoretical results.
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investigation of dynamic mode i Matrix Crack fiber bundle interaction in composites using caustics
Composites Part B-engineering, 2016Co-Authors: Can Tang, Wenfeng Hao, Yanan YuanAbstract:Abstract In this work, the dynamic mode I Matrix Crack-fiber bundle interaction was studied using caustics. First, the strain fields at the dynamic mode I Matrix Crack tip ahead of the fiber bundles were deduced using transformation toughening theory. Subsequently, the caustic equation at mode I dynamic Matrix Crack tip ahead of the fiber bundles was established to investigate the influences of the fiber bundle and the Crack propagating velocity on the initial curves and caustic curves at the dynamic Matrix Crack tip. Finally, a series of dynamic caustic spots surrounding the propagating Crack tip were recorded using optical caustic experiment, and dynamic stress intensity factor were extracted from the shadow spots.
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photoelastic analysis of Matrix Crack tilted fiber bundle interaction
Polymer Testing, 2016Co-Authors: Wenfeng Hao, Jianguo Zhu, Qi Zhu, Yanan YuanAbstract:Abstract Matrix Crack-tilted fiber bundle interaction was explored using photoelasticity. First, the isochromatic fringe patterns near the Matrix Crack tip, either shielded by a tilted fiber bundle or crossed by a broken fiber bundle, were observed. Then, the stress intensity factors of Cracks at varying distances from the tilted fiber bundle were extracted from the isochromatic fringe patterns. Finally, finite element simulation was conducted in ABAQUS software to verify the experimental results, and the difference between photoelasticity measurement and FEM simulation were discussed. The results show that the mode I stress intensity factor of the Crack near a tilted fiber bundle increases with the increase of Crack length and decreases with the increase of the Young's modulus of the fiber bundle. However, the mode II stress intensity factor, which clearly increases as Crack length increased and, as opposed to mode I, increases as the Young's modulus of the fiber bundle increased.
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study on the effect of inclusion shape on Crack inclusion interaction using digital gradient sensing method
Journal of Adhesion Science and Technology, 2015Co-Authors: Wenfeng Hao, Can Tang, Yanan YuanAbstract:The effect of inclusion shape on the mode I stress intensity factor of the Matrix Crack interaction with a rigid inclusion was studied experimentally using digital gradient sensing (DGS) method. First, the noncontact optical measurement system of DGS was built up, and the specimens with different shapes of inclusion ahead of Matrix Crack were performed using transparent epoxy resin. Then, the angular deflection contour at the Crack tip with different shapes of inclusions was obtained, and the stress intensity factors were extracted from the stress gradient filed based on least square fitting. Finally, a numerical simulation was conducted on the same problem using ABAQUS, and the stress intensity factors computed from FEM were compared with the experimental results. The results show that the stress intensity factors extracted from the stress gradient filed are agreed well with the numerical and theoretical results.
Shengyang Pang - One of the best experts on this subject based on the ideXlab platform.
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effects of gradual Matrix Crack closure on the constitutive behavior of sic sic composites upon unloading
Ceramics International, 2017Co-Authors: Sheng Zhang, Xiguang Gao, Hongnian Dong, Yingdong Song, Shengyang PangAbstract:Abstract Gradual Matrix closure and its effects on the constitutive behavior of SiC/SiC composites are examined in the present study. Real-time Matrix Crack detection and a macroscopic loading–unloading tensile test are performed on SiC/SiC minicomposites. To verify the effects of Matrix Crack closure, stress-strain responses under loading and unloading with and without Crack closure are discussed. The experimental and numerical results show that Matrix Cracks close gradually upon unloading, and gradual Matrix closure greatly reduces the unloading stiffness.
John W. Holmes - One of the best experts on this subject based on the ideXlab platform.
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Effect of loading rate on the monotonic tensile behavior of continuous-fiber-reinforced glass-ceramic Matrix composit
Journal of the American Ceramic Society, 1996Co-Authors: Bent F. Sørensen, John W. HolmesAbstract:The stress-strain behavior of a continuous-fiber-reinforced ceramic Matrix composite has been measured over a wide range of loading rates (0.01 to 500 MPa/s). It was found that the loading rate has a strong effect on almost every feature of the stress-strain curve: the proportionality stress, the composite strength and failure strain increase with increasing loading rate. The microstructural damage varies also with the loading rate; with increasing loading rate, the average Matrix Crack spacing increases and the average fiber pullout length decreases. Using simple models, it is suggested that these phenomena are caused partly by time-dependent Matrix Cracking (due to stress corrosion) and partly by an increasing interfacial shear stress with loading rate.
Yingdong Song - One of the best experts on this subject based on the ideXlab platform.
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effects of gradual Matrix Crack closure on the constitutive behavior of sic sic composites upon unloading
Ceramics International, 2017Co-Authors: Sheng Zhang, Xiguang Gao, Hongnian Dong, Yingdong Song, Shengyang PangAbstract:Abstract Gradual Matrix closure and its effects on the constitutive behavior of SiC/SiC composites are examined in the present study. Real-time Matrix Crack detection and a macroscopic loading–unloading tensile test are performed on SiC/SiC minicomposites. To verify the effects of Matrix Crack closure, stress-strain responses under loading and unloading with and without Crack closure are discussed. The experimental and numerical results show that Matrix Cracks close gradually upon unloading, and gradual Matrix closure greatly reduces the unloading stiffness.
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Estimate interface frictional coefficient of ceramic Matrix composites from hysteresis loops
Journal of Composite Materials, 2010Co-Authors: Yingdong SongAbstract:An approach to estimate fiber/Matrix interface frictional coefficient of ceramic Matrix composites under fatigue loading is developed by means of hysteresis loops. The Coulomb friction law is adopted to describe the interface shear stress in the debonded region. The Matrix Crack space and interface debonded length are obtained by Matrix statistical Cracking model and fracture mechanics interface debonding criterion. The hysteresis loops of four different cases are derived based on the damage mechanisms of fiber sliding relative to Matrix in the debonded region during unloading and subsequent reloading. The hysteresis loss energy corresponding to different cycle is formulated in terms of interface frictional coefficient. By comparing the experimental hysteresis loss energy with computational values, the interface frictional coefficient of three different ceramic Matrix composites under fatigue loading is derived.
