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Computer Modeling in Engineering & Sciences 2025年第1期142卷 329-355页

作者： yufeng Xing Ye Yuan Gen Li Institute of Solid Mechanics Beihang University(BUAA)Beijing100191China

The separation-of-variable(SOV)methods,such as the improved SOV method,the variational SOV method,and the extended SOV method,have been proposed by the present authors and coworkers to obtain the closed-form analytical solutions for free vibration and eigenbuckling of rectangular plates and circular cylindrical *** taking the free vibration of rectangular thin plates as an example,this work presents the theoretical framework of the SOV methods in an instructive way,and the bisection–based solution procedures for a group of nonlinear eigenvalue ***,the explicit equations of nodal lines of the SOV methods are presented,and the relations of nodal line patterns and frequency orders are *** is concluded that the highly accurate SOV methods have the same accuracy for all frequencies,the mode shapes about repeated frequencies can also be precisely captured,and the SOV methods do not have the problem of missing roots as well.

关键词： Separation-of-variable method Rayleigh quotient nodal line eigenvalue equation bisection method

功能可恢复SFCB-ECC-混凝土桥墩抗震性能

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哈尔滨工业大学学报 2025年第1期57卷 13-23页

作者：白玉磊靳晓杰张玉峰韩世文城市与工程安全减灾教育部重点实验室(北京工业大学) 北京100124 哈尔滨工业大学(深圳)土木与环境工程学院广东深圳518055

为实现高耐久功能可恢复结构,设计了钢-FRP复合筋(steel-FRP composite bar,SFCB)替代钢筋,塑性铰区使用高延性水泥基复合材料(engineered cementitious composites,ECC)替代混凝土的新型组合柱。在0.13轴压比下,对SFCB-ECC-混凝土组合... 详细信息

为实现高耐久功能可恢复结构,设计了钢-FRP复合筋(steel-FRP composite bar,SFCB)替代钢筋,塑性铰区使用高延性水泥基复合材料(engineered cementitious composites,ECC)替代混凝土的新型组合柱。在0.13轴压比下,对SFCB-ECC-混凝土组合柱进行低周往复荷载试验研究。评估了SFCB中FRP体积分数(0%,43.6%,100%)和塑性铰区基体类型(ECC,混凝土)对组合柱抗震性能和可恢复性的影响。之后通过OpenSees进行了轴压比、SFCB配筋率和ECC强度的参数分析。结果表明:SFCB可使试件获得稳定的二次刚度,在2%位移角前,试件无需修复即可快速恢复原有功能;组合柱残余变形随SFCB中FRP体积分数增加而减少,但其初始刚度和峰值承载力也相应降低;在塑性铰区使用ECC可进一步减少残余位移,同时显著提高峰值承载力和延性;参数分析显示增大轴压比将提高SFCB-ECC-混凝土组合柱承载力,但会降低延性;随SFCB配筋率和ECC强度提高,组合柱承载力也相应增大;在实际工程中可合理设计SFCB和ECC材料特性以满足特定结构刚度、强度和可修复性的要求。

关键词：桥梁工程组合柱抗震性能 OpenSees 钢-FRP复合筋高延性水泥基复合材料可恢复

Current situation and development trend of titanium metal industry in China

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International Journal of Minerals,Metallurgy and Materials 2022年第4期29卷 599-610页

作者： Guanzhou Qiu yufeng Guo School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China

Titanium metal and alloy are key materials for technological development,which significantly promote the development of the hightech economy in *** consumption of high-end titanium materials and the developmental level of the titanium industry are important indexes of a country’s comprehensive ***,at present,the application amount and level of high-end titanium materials in China are limited by many factors,including the dependence of raw materials on imports,high processing cost,and structural imbalance of *** on the characteristics of titanium resources and the current situation of the titanium industry,the whole titanium industrial chain in China should be *** the quality of raw materials is important to produce low-cost,high-end titanium materials using titanium resources with high calcium and magnesium contents in the Panxi *** addition,the steel-titanium joint production is a vital step to reduce the processing cost of titanium ***,the consumption structure of titanium materials should be completed to expand their *** implementing these suggestions,the overall level of China’s titanium industry will be greatly improved,thereby rapidly establishing an advanced scientific and technological country.

关键词： titanium titanium resources prodcution cost high-end titanium material steel-titanium joint prodcution

Analytical solution methods for eigenbuckling of symmetric cross-ply composite laminates

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Chinese Journal of Aeronautics 2017年第1期30卷 282-291页

作者： Xing yufeng Xiang Wei Institute of Solid Mechanics Beihang University School of Mechanical Engineering Southwest Jiaotong University

Based on the first-order shear deformation theory, this paper explores the analytical methods for eigenbuckling of symmetric cross-ply rectangular composite laminates with a pair of parallel edges simply supported and the remaining two edges arbitrarily constrained. The main contribution of present paper lies in two aspects： one is to present a simple and effective analytical method, namely, the separation-of-variables method, which can generate the closed-form buckling solutions without any computational difficulty; the other is to incorporate the accurate computation method of exponential matrix into the state space technique to avoid the inevitable numerically illconditioned problems reported in several literatures. The results obtained via both analytical methods are identical, and a good agreement with their counterparts in literature is observed. The separation-of-variables method can generate exact solutions within 1 s, which is impossible if the state space method is employed. Besides, the combination of the accurate computation method of exponential matrix and the state space method greatly improves the computational efficiency and gives correct results compared with the straightforward use of state space method.

关键词： Accurate computation Analytical solution Composite laminates Eigenbuckling Separation of variablesState space

Flat-plate hypersonic boundary-layer ?ow instability and transition prediction considering air dissociation

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Applied Mathematics and Mechanics(English Edition) 2019年第5期40卷 719-736页

作者： yufeng HAN Wei CAO Department of Mechanics Tianjin University

The effects of air dissociation on ?at-plate hypersonic boundary-layer ?ow instability and transition prediction are studied. The air dissociation reactions are assumed to be in the chemical equilibrium. Based on the ?at-plate boundary layer, the ?ow stability is analyzed for the Mach numbers from 8 to 15. The results reveal that the consideration of air dissociation leads to a decrease in the unstable region of the ?rst-mode wave and an increase in the maximum growth rate of the second mode. High frequencies appear earlier in the third mode than in the perfect gas model, and the unstable region moves to a lower frequency region. When the Mach number increases, the second-mode wave dominates the transition process, and the third-mode wave has little effect on the transition. Moreover, when the Mach number increases from 8 to 12, the N-factor envelope becomes higher, and the transition is promoted. However, when the Mach number exceeds 12, the N-factor envelope becomes lower, and the transition is delayed. The N-factor envelope decreases gradually with the increase in the altitude or Mach number.

关键词： air dissociation transition prediction boundary layer

Multiscale eigenelement method for periodical composites: A review

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Chinese Journal of Aeronautics 2019年第1期32卷 104-113页

作者： yufeng XING Yahe GAO Institute of Solid Mechanics Beihang University

Based on the eigenvector expansion idea, the Multiscale Eigenelement Method(MEM)was proposed by the author and co-workers. MEM satisfies two equivalent conditions, one condition is the equivalence of strain energy, and the other is the deformation similarity. These two equivalent conditions character the structure-preserving property of a multiscale analysis method. The equivalence of strain energy is necessary for achieving accurate macro behaviors such as lower order frequencies, while the deformation similarity is essential for predicting accurate micro behaviors such as stresses. The MEM has become a powerful multiscale method for the analysis of composite structures because of its high accuracy and efficiency. In this paper, the research advances of MEM are reviewed and all types of eigenelement methods are compared, focusing on superiorities and deficiencies from practical viewpoint. It is concluded that the eigenelement methods with smooth shape functions are more suitable for the analysis of macro behaviors such as lower order frequencies, and the eigenelement methods with piecewise shape functions are suitable for the analysis of both macro and micro behaviors.

关键词： Composite Deformation similarity Eigenelement Energy equivalence Mechanical analysis Multiscale

Novel Magnesium Alloys Developed for Biomedical Application:A Review

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Journal of Materials Science & Technology 2013年第6期29卷 489-502页

作者： Nan Li yufeng Zheng State Key Laboratory for Turbulence and Complex System and Department of Materials Science and Engineering College of EngineeringPeking University

There is an increasing interest in the development of magnesium alloys both for industrial and biomedical applications. Industrial interest in magnesium alloys is based on strong demand of weight reduction of transportation vehicles for better fuel efficiency, so higher strength, and better ductility and corrosion resistance are required. Nevertheless, biomedical magnesium alloys require appropriate mechanical properties, suitable degradation rate in physiological environment, and what is most important, biosafety to human body. Rather than simply apply commercial magnesium alloys to biomedical field, new alloys should be designed from the point of view of nutriology and toxicology. This article provides a review of state-of-the-art of magnesium alloy implants and devices for orthopedic, cardiovascular and tissue engineering applications. Advances in new alloy design, novel structure design and surface modification are overviewed. The factors that influence the corrosion behavior of magnesium alloys are discussed and the strategy in the future development of biomedical magnesium alloys is proposed.

关键词： Biomaterials Magnesium alloys Biodegradation Mechanical property Biocompatibility

Sandman is a Sleep Switch in Drosophila

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Neuroscience Bulletin 2016年第5期32卷 503-504页

作者： yufeng Pan Institute of Life Sciences Southeast University Nanjing 210096 China

Sleep is a universal process with vital *** deprived of sleep for a long period of time will *** its crucial functions,fundamental questions about sleep remain *** instance,why do animals sleep since it disconnects an... 详细信息

关键词： instance Drosophila switch universal vital danger really beginning homeostasis questions

Scaling of energy spectra in weakly compressible turbulence

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Acta Mechanica Sinica 2017年第3期33卷 500-507页

作者： yufeng Dong Guowei He The State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences School of Engineering Sciences University of Chinese Academy of Sciences

We find an asymptotic expression for the characteristic timescales of decorrelation processes in weakly compressible and isothermal turbulence. This result is used in the Eddy-Damped Quasi-Normal Markovian equation to derive the scalings of compressible energy spectra: (1) if the acoustic waves are dominant, the compressible energy spectra exhibit \(-7/3\) scaling; (2) if local eddy straining is dominant, the compressible energy spectra are scaled as \(-3\). Meanwhile, the energy spectra of incompressible components display the same scaling of \(-5/3\) as those in incompressible turbulence. The direct numerical simulations of weakly compressible turbulence are used to examine the scaling.

关键词： Compressible turbulence Energy spectra Two-point closure Space-time correlation

Measuring Fuel Stratification in Cylinder of a Spark Ignition Engine by a Two-Tracer PLIF System

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工程热物理学报 2013年第9期34卷 1755-1761页

作者： LI yufeng ZHAO Hua China North Engine Research Institute Tianjin 300400 China Brunel University Uxbridge UB8 3PH UK

A two-tracer PLIF system was developed to measure fuel stratification in cylinder of a spark ignition engine which is achieved by producing a strong tumbling flow and introducing two fuels through two separate intake *** tracers,3-pentanone and N,N-dimethylaniline(DMA),were doped in two fuels,hexane and iso-octane,respectively.A spectroscopic test result showed that when subject to irradiation by a XeCl Excimer laser(308 nm),3-pentanone and DMA emit fluorescence within different wavelength *** fluorescence can be separated by two band-pass optical filters and recorded into a single intensified CCD camera through a specially designed image doubling *** advantage of the measurement method is that both fuel distributions in cylinder can be visualized by one *** results showed that two fuels were well stratified in the cylinder.

关键词： Spark ignition engine PLIF Charge stratification