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学者姓名:王景甫
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摘要 :
The volume fraction of the carbon nanotube (CNT) plays a key role in ensuring the performance of the CNT reinforced polymer composite, especially under the severe vibration, which leads to the resonance and failure of the composite structure. In this paper, a bottom-up multiscale method is adopted to study the effect of the CNT volume fractions on the nonlinear vibration of the poly (methyl methacrylate) (PMMA)/CNT composite. According to the molecular simulation, the longitudinal, transverse and shear moduli of the PMMA/CNT nanocomposites are found to increase with the increasing CNT volume fractions. Substituting the simulated moduli into the extended rule of mixtures (EROM), the efficiency parameters of the PMMA/CNT composite with various CNT volume fractions are derived based on a homogenization approach. The derived efficiency parameters are used in the functionally graded (FG)-based EROM to obtain the expressions of the longitudinal, transverse and shear moduli of the macroscopic composite plate, so as to obtain the constitutive equation for the nonlinear vibrations of the FG-based PMMA/CNT composite plate. The subsequent meshless simulation results demonstrate that the natural frequencies of the FG-based composite plate increase with the increasing volume fractions, whereas the ratios of the nonlinear to linear frequencies decrease. Using the bottom-up multiscale analysis, the macroscopic vibration responses are analyzed for the PMMA/CNT composites with the CNT volume fractions up to 9.0%, which provides a paradigm of the design of the PMMA/CNT composite by considering the CNT volume fraction effect.
关键词 :
Meshless simulation Meshless simulation Molecular dynamics Molecular dynamics CNT composite CNT composite Nonlinear vibration Nonlinear vibration CNT volume fraction CNT volume fraction PMMA PMMA
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GB/T 7714 | Wang, J. F. , Yang, J. P. , Tam, L-H et al. Effect of CNT volume fractions on nonlinear vibrations of PMMA/CNT composite plates: A multiscale simulation [J]. | THIN-WALLED STRUCTURES , 2022 , 170 . |
MLA | Wang, J. F. et al. "Effect of CNT volume fractions on nonlinear vibrations of PMMA/CNT composite plates: A multiscale simulation" . | THIN-WALLED STRUCTURES 170 (2022) . |
APA | Wang, J. F. , Yang, J. P. , Tam, L-H , Zhang, W. . Effect of CNT volume fractions on nonlinear vibrations of PMMA/CNT composite plates: A multiscale simulation . | THIN-WALLED STRUCTURES , 2022 , 170 . |
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摘要 :
Owing to the excellent mechanical properties, polymethyl methacrylate (PMMA)/carbon nanotube (CNT) composite has been increasingly adopted in the aerospace field, which is usually subjected to various temperature conditions and supersonic aerodynamic loads. Using a molecular dynamics (MD)-based multiscale simulation, the nonlinear forced vibration of PMMA/CNT composite plate is investigated under coupled temperature and aerodynamic load conditions. The longitudinal, transverse and shear moduli of PMMA/single-walled CNT (SWCNT) nanocomposite obtained from MD simulation at different temperature and pressure levels are substituted into the extended rule of mixtures to establish the constitutive equations of PMMA/CNT composite plate. Meanwhile, Poisson's ratio and thermal expansion coefficient of nanocomposite are used in the constitutive equations. Based on the third-order shear deformation theory, von Karman nonlinear strain-displacement relation and Hamilton's principle, the partial differential equation of composite plate is derived, which is reduced into a set of coupled ordinary differential equations by applying Galerkin method and is solved using the fourth-order Runge-Kutta method. The bifurcation diagrams, phase portraits, time histories and Poincare maps of composite plate are obtained under the complex loads including transverse harmonic excitation and aerodynamic pressure, which are applied to analyze the dynamic characteristics of system. This study reveals the nonlinear dynamic characteristics of PMMA/CNT composite plate, which contributes to the prediction of long-term performance of composite materials in aerospace field.
关键词 :
Nonlinear dynamics Nonlinear dynamics Efficiency parameter Efficiency parameter Aerodynamic Aerodynamic Composite structure Composite structure Multiscale simulation Multiscale simulation
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GB/T 7714 | Wang, J. F. , Shi, S. Q. , Liu, Y. Z. et al. Multiscale simulation of temperature- and pressure-dependent nonlinear dynamics of PMMA/CNT composite plates [J]. | NONLINEAR DYNAMICS , 2022 , 109 (3) : 1517-1550 . |
MLA | Wang, J. F. et al. "Multiscale simulation of temperature- and pressure-dependent nonlinear dynamics of PMMA/CNT composite plates" . | NONLINEAR DYNAMICS 109 . 3 (2022) : 1517-1550 . |
APA | Wang, J. F. , Shi, S. Q. , Liu, Y. Z. , Yang, J. P. , Tam, Lik-ho . Multiscale simulation of temperature- and pressure-dependent nonlinear dynamics of PMMA/CNT composite plates . | NONLINEAR DYNAMICS , 2022 , 109 (3) , 1517-1550 . |
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摘要 :
氨气作为一种可持续和可再生燃料近年来引起研究者广泛的兴趣,然而由于较低的层流火焰传播速度和较高的NO排放,需要对此进行进一步研究。本文通过数值研究的方法,计算了NH3-H2-空气火焰的火焰传播速度和NO排放量,并且进行了火焰的详细反应敏感性分析,研究了化学当量条件下氢气对于火焰传播速度以及NO影响的原因。结果表明,随着燃料中H2成分的增加,改变了火焰中自由基的浓度,提升了火焰中重要反应的反应速率,同时对反应路径有着较为明显的影响,从而增强了火焰传播速度以及NO的摩尔分数。
关键词 :
Sensitivity Analysis Sensitivity Analysis NO排放 NO排放 NO Emission NO Emission Reaction Path Reaction Path Ammonia Fuel Ammonia Fuel Flame Propagation Velocity Flame Propagation Velocity 反应路径 反应路径 火焰传播速度 火焰传播速度 敏感性分析 敏感性分析 氨燃料 氨燃料
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GB/T 7714 | 张晓磊 , 王景甫 , 陈颖 et al. NH3-H2-空气的层流火焰传播特性和NO排放特性 [J]. | 可持续能源 , 2021 , 11 (01) : 1-10 . |
MLA | 张晓磊 et al. "NH3-H2-空气的层流火焰传播特性和NO排放特性" . | 可持续能源 11 . 01 (2021) : 1-10 . |
APA | 张晓磊 , 王景甫 , 陈颖 , 李丛豪 . NH3-H2-空气的层流火焰传播特性和NO排放特性 . | 可持续能源 , 2021 , 11 (01) , 1-10 . |
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摘要 :
NH<sub>3</sub>-H<sub>2</sub>-空气的层流火焰传播特性和NO排放特性
关键词 :
NO排放 NO排放 反应路径 反应路径 反应速率 反应速率 可再生燃料 可再生燃料 摩尔分数 摩尔分数 敏感性分析 敏感性分析 火焰传播特性 火焰传播特性 火焰传播速度 火焰传播速度
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GB/T 7714 | 张晓磊 , 王景甫 , 陈颖 et al. NH<sub>3</sub>-H<sub>2</sub>-空气的层流火焰传播特性和NO排放特性 [J]. | 张晓磊 , 2021 , 11 (1) : 1-10 . |
MLA | 张晓磊 et al. "NH<sub>3</sub>-H<sub>2</sub>-空气的层流火焰传播特性和NO排放特性" . | 张晓磊 11 . 1 (2021) : 1-10 . |
APA | 张晓磊 , 王景甫 , 陈颖 , 李丛豪 , 可持续能源 . NH<sub>3</sub>-H<sub>2</sub>-空气的层流火焰传播特性和NO排放特性 . | 张晓磊 , 2021 , 11 (1) , 1-10 . |
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摘要 :
To study the laminar premixed flame characteristics of methane under an O-2/CO2 atmosphere in high pressure, a new simplified chemical mechanism (44 steps and 19 species) was extracted from the GRI-Mech 3.0 mechanism. The sensitivity coefficient analysis method is used to retain the elementary reactions that have great influence on the target parameters and remove other secondary elementary reactions. Meanwhile, the closeness of the simplified mechanism initially obtained was verified. The results of the laminar burning velocities, the distribution of the main species, and the ignition delay time were compared between the two mechanisms for the premixed flame and the ignition process. Overall, the simplified mechanisms performed fairly well over a wide range of pressure, equivalence ratio, and fuel mixture composition.
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GB/T 7714 | Chen, Ying , Wang, Jingfu , Li, Conghao et al. Development and Verification of the New Simplified Mechanism for CH4/O-2/CO2 Laminar Premixed Flame under High Pressure [J]. | ACS OMEGA , 2021 , 6 (29) : 18569-18575 . |
MLA | Chen, Ying et al. "Development and Verification of the New Simplified Mechanism for CH4/O-2/CO2 Laminar Premixed Flame under High Pressure" . | ACS OMEGA 6 . 29 (2021) : 18569-18575 . |
APA | Chen, Ying , Wang, Jingfu , Li, Conghao , Zhang, Xiaolei . Development and Verification of the New Simplified Mechanism for CH4/O-2/CO2 Laminar Premixed Flame under High Pressure . | ACS OMEGA , 2021 , 6 (29) , 18569-18575 . |
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摘要 :
Bus rides have become a routine choice for the large population to travel in Beijing. By the end of November 2020, 82.84% of all buses in Beijing had switched to electric vehicles. A solution to the problem of charging a huge number of battery electric buses (BEBs) in urban areas, especially in crowded cities with large populations, has to be found. In the present paper, a calculation model based on the levelized cost of electricity (LCOE) is established for comparison and analysis of the BEB charging. The calculation results show that the hybrid charging mode is economically feasible. Moreover, from the perspectives of optimizing operation shifts and responding to emergency situations, hybrid charging mode is applicable to the current electric bus system. The calculation results also show that the use of BEBs as the main ground public transportation in Beijing can substantially reduce CO2 emissions and save huge fuel costs. Its application is a very wise choice. The analogy calculation on Tongzhou District, the sub center of Beijing which is under construction, shows that the use of BEBs in Tongzhou can reduce CO2 emissions by about 34.6% on average compared with fuel buses. The population is the main influencing factor of analogy calculation.
关键词 :
Energy consumption Energy consumption Tongzhou district Tongzhou district Charging system Charging system Battery electric bus Battery electric bus Carbon dioxide emission Carbon dioxide emission Beijing city Beijing city
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GB/T 7714 | Zhang, Xinxin , Nie, Shangyang , He, Maogang et al. Charging system analysis, energy consumption, and carbon dioxide emissions of battery electric buses in Beijing [J]. | CASE STUDIES IN THERMAL ENGINEERING , 2021 , 26 . |
MLA | Zhang, Xinxin et al. "Charging system analysis, energy consumption, and carbon dioxide emissions of battery electric buses in Beijing" . | CASE STUDIES IN THERMAL ENGINEERING 26 (2021) . |
APA | Zhang, Xinxin , Nie, Shangyang , He, Maogang , Wang, Jingfu . Charging system analysis, energy consumption, and carbon dioxide emissions of battery electric buses in Beijing . | CASE STUDIES IN THERMAL ENGINEERING , 2021 , 26 . |
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摘要 :
A comprehensive numerical investigation of the uncoupled chemical, thermal, and transport effects of CO2 on the temperature of CH4/O-2 counterflow diffusion flame under high pressure up to 5 atm was conducted. Three pairs of artificial species were introduced to distinguish the chemical effect, thermal effect, and the transport effect of CO2 on the flame temperature. The numerical results showed that both the chemical effect and the thermal effect of the CO2 dilution in the oxidizer side can decrease the flame temperature significantly, while the transport effect of CO2 can only slightly increase the flame temperature and can even be ignored. The reduction value of the temperature caused by the chemical effect of CO2 grows linearly, while that caused by the thermal effect increases exponentially. The RPchem and RPthermal are defined to explain the temperature reduction percentage due to the chemical effect and the thermal effect of CO2 in the total temperature reduction caused by CO2 dilution, respectively. The RPchem decreases with the increase of the pressure, the strain rate, and the CO2 dilution ratio, while the RPthermal thermal behaves in the opposite manner. In the above conditions, the chemical effect plays a dominant role on the flame temperature reduction.
关键词 :
chemical effect chemical effect CO2 dilution CO2 dilution counterflow flame counterflow flame methane methane thermal effect thermal effect
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GB/T 7714 | Chen, Ying , Wang, Jingfu , Zhang, Xiaolei et al. Comparisons of the Uncoupled Effects of CO2 on the CH4/O-2 Counterflow Diffusion Flame under High Pressure [J]. | APPLIED SCIENCES-BASEL , 2021 , 11 (4) . |
MLA | Chen, Ying et al. "Comparisons of the Uncoupled Effects of CO2 on the CH4/O-2 Counterflow Diffusion Flame under High Pressure" . | APPLIED SCIENCES-BASEL 11 . 4 (2021) . |
APA | Chen, Ying , Wang, Jingfu , Zhang, Xiaolei , Li, Conghao . Comparisons of the Uncoupled Effects of CO2 on the CH4/O-2 Counterflow Diffusion Flame under High Pressure . | APPLIED SCIENCES-BASEL , 2021 , 11 (4) . |
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摘要 :
The effects (chemical, thermal, transport, and radiative) of CO2 added to the fuel side and oxidizer side on the flame temperature and the position of the flame front in a one-dimensional laminar counterflow diffusion flame of methane/N-2/O-2 were studied. Overall CO2 resulted in a decrease in flame temperature whether on the fuel side or on the oxidizer side, with the negative effect being more obvious on the latter side. The prominent effects of CO2 on the flame temperature were derived from its thermal properties on the fuel side and its radiative properties on the oxidizer side. The results also highlighted the differences in the four effects of CO2 on the position of the flame front on different sides. In addition, an analysis of OH and H radicals and the heat release rate of the main reactions illustrated how CO2 affects the flame temperature.
关键词 :
CH4 counterflow diffusion flame CH4 counterflow diffusion flame CO2 dilution CO2 dilution flame front flame front temperature temperature
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GB/T 7714 | Chen, Ying , Wang, Jingfu , Zhang, Xiaolei et al. The Effects of CO2 Additional on Flame Characteristics in the CH4/N-2/O-2 Counterflow Diffusion Flame [J]. | MOLECULES , 2021 , 26 (10) . |
MLA | Chen, Ying et al. "The Effects of CO2 Additional on Flame Characteristics in the CH4/N-2/O-2 Counterflow Diffusion Flame" . | MOLECULES 26 . 10 (2021) . |
APA | Chen, Ying , Wang, Jingfu , Zhang, Xiaolei , Li, Conghao . The Effects of CO2 Additional on Flame Characteristics in the CH4/N-2/O-2 Counterflow Diffusion Flame . | MOLECULES , 2021 , 26 (10) . |
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摘要 :
This paper investigates the thermal vibration and buckling of the functionally graded carbon nanotube reinforced composite (FG-CNTRC) quadrilateral plate using the meshless method. Four distributions of the reinforcements along the thickness direction are considered, which are the uniform distributions (UD), FG-V, FG-O and FG-X. The corresponding effective material properties including Young's modulus, mass density, Poisson's ratio and thermal expansion coefficients are estimated by the rule of mixture with the CNT efficiency parameters accounting for the size-dependence. The first-order shear deformation theory (FSDT) with the consideration of thermal effects is employed. Based on Hamilton's principle and the moving least square (MLS) approximation, the discrete governing equations for the vibration of the FG-CNTRC plate are derived. The free vibration of the regular and irregular plates with and without the temperature effect are considered respectively, and the corresponding natural frequencies and mode shapes are obtained by the eigenvalue problem. The stability analysis of the uniaxial and biaxial mechanical and thermal buckling are also conducted subsequently. The effects of the volume fraction, distribution pattern, geometrical characteristics and temperature on the buckling behaviors of the CNTRC quadrilateral plate are discussed in detail. © 2020 Elsevier Masson SAS
关键词 :
Buckling Buckling Carbon nanotubes Carbon nanotubes Eigenvalues and eigenfunctions Eigenvalues and eigenfunctions Elastic moduli Elastic moduli Least squares approximations Least squares approximations Plates (structural components) Plates (structural components) Reinforcement Reinforcement Shear deformation Shear deformation Shear flow Shear flow Structural panels Structural panels Thermal expansion Thermal expansion Vibration analysis Vibration analysis
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GB/T 7714 | Wang, J.F. , Cao, S.H. , Zhang, W. . Thermal vibration and buckling analysis of functionally graded carbon nanotube reinforced composite quadrilateral plate [J]. | Solids , 2021 , 85 . |
MLA | Wang, J.F. et al. "Thermal vibration and buckling analysis of functionally graded carbon nanotube reinforced composite quadrilateral plate" . | Solids 85 (2021) . |
APA | Wang, J.F. , Cao, S.H. , Zhang, W. . Thermal vibration and buckling analysis of functionally graded carbon nanotube reinforced composite quadrilateral plate . | Solids , 2021 , 85 . |
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摘要 :
In order to solve the problem of energy utilization of urban plastic garbage and livestock manure, this paper developed a method and technology to produce high-calorific value biomass char fuel through low-temperature pyrolysis in drying, thermal decomposition, extrusion and other processes, using urban plastic garbage and chicken manure as raw materials which are difficult to recycle. Established the verification experiment device in Chiba prefecture, with a 15% plastic + 85% chicken manure as raw material, the preparation of the calorific value of 5500-6000 kcal/kg of high calorific value of biomass char fuel. The ignition temperature, burning-out temperature, comprehensive combustion characteristic index S and other combustion characteristics of fuel were analysed by thermogravimetric experiments. The kinetic analysis of fuel was carried out by means of Coats-Redfern method. The pre-exponential factor and activation energy of combustion temperature range were obtained. The results show that the volatilization of biomass char fuel exceeds 60%, the ignition temperature and burnout temperature are low, and the ignition performance is good and the combustion speed is fast. The fuel calorific value is 24985kJ/kg (5976kcal/kg), the activation energy is 55.11kJ/mol, and the comprehensive combustion characteristic index S is 4.57 10-8 min-2K-3, which is similar to bituminous coal. In addition, biomass char fuel contains almost no sulphur and does not require desulfurization equipment. It is a kind of biomass fuel that can achieve clean and efficient combustion and replace coal. © Published under licence by IOP Publishing Ltd.
关键词 :
Temperature Temperature Activation energy Activation energy Bituminous coal Bituminous coal Agriculture Agriculture Animals Animals Waste incineration Waste incineration Fertilizers Fertilizers Coal combustion Coal combustion Decomposition Decomposition Biomass Biomass Calorific value Calorific value Ignition Ignition Coal industry Coal industry Energy utilization Energy utilization Manures Manures Fuels Fuels
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GB/T 7714 | Wang, Jingfu , Matsushita, Takamichi , Yuminaga, Jikyou et al. Study on the Preparation Method and Combustion Characteristics of Biomass Char Fuel Made from Chicken Manure Synergistic Plastic Waste [C] . 2021 . |
MLA | Wang, Jingfu et al. "Study on the Preparation Method and Combustion Characteristics of Biomass Char Fuel Made from Chicken Manure Synergistic Plastic Waste" . (2021) . |
APA | Wang, Jingfu , Matsushita, Takamichi , Yuminaga, Jikyou , Jia, Hongxin . Study on the Preparation Method and Combustion Characteristics of Biomass Char Fuel Made from Chicken Manure Synergistic Plastic Waste . (2021) . |
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