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Journal of Oceanology and limnology 2022年第3期40卷 1097-1109页

作者： Mengyu li Yuqiang li Tengfei XING yulong li Jinxian liU CAS Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Ecology and Environmental Science Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China

Periwinkle littoraria sinensis is a widely distributed gastropod in rocky intertidal zone of the northwestern Pacifi *** examine genetic diversity and genetic connectivity among coastal populations of *** in China,1636 pairs of primers were successfully designed using whole-genome shotgun sequencing,de novo assembly,and a bioinformatics pipeline *** highly variable polymorphic markers were selected to genotype 351 individuals from 15 *** of nine microsatellite loci were retained for population genetic analysis,and weak genetic differentiation among populations were detected,suggesting high gene flow among *** long planktonic larval duration of *** might have played an important role in the high gene flow among populations.A tendency of genetic differentiation between north and south populations of *** was detected,which might be resulted from isolation due to lowered sea level in the last glacial ***,the newly founded populations along the coast of Jiangsu Province were closely related to populations to the south of the Changjiang(Yangtze)River estuary,suggesting that the main source of the newly founded populations is from natural rocky populations south of the estuary.

关键词： population genetics littoraria sinensis gastropod simple-sequence repeats

Experimental study on spray cooling under reduced pressures

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Science China(Technological Sciences) 2019年第2期62卷 349-355页

作者： PENG Can XU XiangHua li Ye Ming li yulong liANG XinGang Key Laboratory for Thermal Science and Power Engineering of Ministry of Education School of Aerospace Engineering Tsinghua University School of Energy and Power Engineering Beihang University

Spay cooling is a complicated flow and heat transfer process affected by multi-factors among which the environmental pressure is extremely important. However the influence of pressure is not investigated sufficiently, especially the reduced pressure. In the present study, spray cooling under low initial environmental partial pressures and vapor partial pressures with R21 are investigated with a closed spray and condensation system. To study the influence of initial environmental partial pressure, different amounts of nitrogen are inflated into the vacuum flash chamber, while the vapor partial pressure is kept constant. To study the influence of vapor partial pressure, a cascade refrigerator is used to condense the vapor with different condensation temperatures so that the vapor partial pressure can be maintained or adjusted, while the initial environmental partial pressure is kept *** experimental results show that the spray cooling power increases monotonically with the increasing spray flow rate in the experimental range, while the cooling efficiency decreases with the increasing spray flow rate. The spray cooling power and cooling efficiency vary with the initial environmental partial pressure or the vapor partial pressure non-monotonously, which indicates there is an optimal pressure for the heat transfer performance. Besides, the mechanism of the non-monotonous variation trend is discussed based on the key aspects including flash evaporation, convection and boiling. Especially, the boiling heat transfer curve is applied to explain the trend.

关键词： spray cooling flash evaporation reduced pressure phase change

基于ESG理念的重大工程弃渣造地项目选址价值评价

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工程管理学报 2024年第1期38卷 106-111页

作者：李玉龙韩岩坤苏涵中央财经大学管理科学与工程学院北京102206 上海交通大学安泰经济与管理学院上海200030

为了强化弃渣造地项目选址的可持续性,本文引入了ESG理念作为决策依据,构建了集成ESG理念的重大工程弃渣造地项目选址价值工程框架,并提出了适用于评价西部复杂艰险地区重大工程弃渣选址造地的ESG功能评价指标体系。在此基础上,结合AHP... 详细信息

为了强化弃渣造地项目选址的可持续性,本文引入了ESG理念作为决策依据,构建了集成ESG理念的重大工程弃渣造地项目选址价值工程框架,并提出了适用于评价西部复杂艰险地区重大工程弃渣选址造地的ESG功能评价指标体系。在此基础上,结合AHP方法给出了确定ESG项下各分量指标的权重及价值工程实施的具体操作步骤,并通过一个具体案例进行操作说明。ESG理念的引入及所构建的功能评价指标体系和弃渣选址造地的价值工程分析方法,有助于提升我国重大工程弃渣处置的可持续能力,助推重大工程弃渣选址造地的科学化和重大工程ESG理念的实现。

关键词：重大工程弃渣造地选址 ESG评价价值工程

Damage sensitivity of a wing-type leading edge structure impacted by a bird

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Chinese Journal of Aeronautics 2023年第5期36卷 328-343页

作者： Jun liU Chunyang ZHANG Bopeng JUAN Zhenhua li Chao ZHANG yulong li School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

On the windward side of an aircraft,the components with higher probability of impact with birds are the wing-type leading edge structures,such as the wing and tail.A study on the damage sensitivity of a wing-type leading edge structure under bird strikes was presented in this ***,a bird strike test was carried out on a *** principles of the bird strike test equipment and method were introduced in detail,including the bird strike test system,bird projectile production process and data acquisition *** dynamic strain measurement results,the high-speed camera videos,and the final deformation and damage morphology observations of the structure were *** on the coupled Smooth Particle Hydrodynamics(SPH)-Finite Element Method(FEM),the commercial software PAM-CRASH was used to simulate the process of a bird strike with the *** good agreement between the finite element simulation results and the experimental results shows that the calculation method and the numerical model presented in this paper were *** this basis,wing-type leading edge structures can be designed by adding triangular *** bird strike resistances of an original structure and improved structure were studied by numerical *** calculated results show that the improved wing-type leading edge structure is less damaged than the original structure under bird *** improved leading edge structure satisfied the anti-bird strike airworthiness requirements,as the thickness of the triangular support was 1.2 mm,and the weight of the structure was reduced by 0.87 kg compared with the original *** indicated that the bird strike resistance of the improved structure is better than that of the original structure,and the improved design of the wing-type leading edge structure presented in this paper is reasonable.

关键词： Bird impact Damage sensitivity FEM SPH Wing-type leading edge

Biaxial tensile behavior of Ti-6Al-4V under proportional loading

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Chinese Journal of Aeronautics 2023年第5期36卷 344-362页

作者： lin QI Yazhou GUO Kanghua JIN Huaipu KANG yulong li School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Impact Dynamics and Engineering Applications Northwestern Polytechnical UniversityXi’an 710072China School of Civil Aviation Northwestern Polytechnical UniversitySuzhou 215699China NPU Yangzi River Delta Research Institute Suzhou 215400China

The biaxial tensile behavior of isotropic Ti-6Al-4 V is characterized in this paper.A novel cruciform specimen was designed and optimized to achieve uniform stress and strain distribution within the gauge *** tensile tests were conducted at three different loading ratios by the biaxial testing *** Digital Image Correlation(DIC)technique was applied to determine strain distribution,and a high-speed camera was employed to record the fracture *** Inverse Analysis(IA)approach with a combined experimental and numerical method was proposed to determine the true stresses at the gauge section of the specimen during biaxial tensile *** results indicate that the initial yield locus can be described by the Cazacu criterion accurately,whereas the Mises criterion can predict better the strengthening behavior of Ti-6Al-4 V in the first quadrant in the principal stress space.

关键词： Biaxial tensile testing Inverse analysis Strengthening behavior Ti-6Al-4V Yield locus

齿轮马达转速/转矩输出脉动的差异化及其最小化

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机械传动 2024年第5期48卷 83-87页

作者：李玉龙侯鑫宇章丽华宋安然宿迁学院机电工程学院江苏宿迁223800 四川五环石化装备有限公司四川成都641300

为了弥补齿轮马达输出脉动现有研究的不足,建立了一套输出脉动最小化的高效解析方法。基于齿轮泵的流量脉动式,推导出马达输出转速/转矩的脉动式,并进行相应的差异化判别;分析了马达脉动最小化与齿数、重合度最大化的关系,并基于无根切... 详细信息

为了弥补齿轮马达输出脉动现有研究的不足,建立了一套输出脉动最小化的高效解析方法。基于齿轮泵的流量脉动式,推导出马达输出转速/转矩的脉动式,并进行相应的差异化判别;分析了马达脉动最小化与齿数、重合度最大化的关系,并基于无根切齿廓的构造特征,由最大齿顶压力角和最小齿顶圆心角,解析出对应于脉动最小化下的齿廓参数。结果表明,马达转矩与泵流量具有相同的理论脉动系数,但小于转速的理论脉动系数;输出脉动的最小化等价于重合度的最大化,重合度的最大化等价于齿顶压力角和齿数的最大化;许可的最大齿顶压力角和最小齿顶圆心角是决定输出脉动最小化程度的两个关键性能参数,齿廓参数均可由二者通过解析方法得出。从而纠正了齿轮马达输出转速/转矩具有相同脉动系数的现有经典结论。

关键词：齿轮马达输出脉动脉动最小化无根切重合度齿数

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A thermo-viscoelastic model for particle-reinforced composites based on micromechanical modeling

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Acta Mechanica Sinica 2021年第3期37卷 402-413,I0001页

作者： Yang Chen Xiaohao Shi Zhenqiang Zhao Zaoyang Guo yulong li School of Civil Aviation Northwestern Polytechnical UniversityXi’an 710072China Institute of Biomedical Engineering and Health Sciences Changzhou UniversityChangzhou 213164China School of Science Harbin Institute of TechnologyShenzhen 518055China

Micromechanics-based constitutive models offer superior ability to estimate the effective mechanical properties for the composites,which greatly promote the computational efficiency in the multiscale analysis for composite *** this work,a thermo-viscoelastic model for particle-reinforced composites is proposed to estimate their thermal-mechanical coupling behaviors in terms of a micromechanics-based homogenization method in the time *** matrix and particles of the composites are modeled as“thermo-rheologically complex”viscoelastic *** temperature-dependent effective elastic strain energy ratios of particle to composite are proposed to evaluate the contributions of the matrix and *** thermo-viscoelastic model for the composites is then formulated by superposing the matrix and particle’s *** element simulations based on the representative volume element models are employed to validate the constitutive model under various thermal-mechanical coupling *** effects of the loading rate,viscous parameter and particle content on the effective thermal-mechanical responses of the composites are also comprehensively *** experimental data from literature are also employed to verify the constitutive *** findings show that the proposed thermo-viscoelastic model can accurately predict the thermal-mechanical coupling behaviors for the particle-reinforced composites.

关键词： Particle-reinforced composites Thermo-viscoelastic model Thermal-mechanical coupling Homogenization method Numerical validation

Highly efficient computation method for hazard quantification of uncontained rotor failure

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Chinese Journal of Aeronautics 2020年第7期33卷 1980-1990页

作者： Zhenqiang ZHAO Peng liU Yan liU Chao ZHANG yulong li Department of Aeronautical Structure Engineering Northwestern Poly technical UniversityXi'an 710072China Shaanxi Key Laboratory of Impact Dynamics and its Engineering Applications Northwestern Polytechnical UniversityXi’an 710072China

Uncontained Engine Rotor Failure(UERF)can cause a catastrophic failure of an aircraft,and the quantitative assessment of the hazards related to UERF is a very important part of safety ***,the procedure for hazard quantification of UERF recommended by the Federal Aviation Administration in advisory circular AC20-128A is cumbersome,as it involves building auxiliary lines and curve *** improve the efficiency and general applicability of the risk angle calculation,a boundary discretization method is developed that involves discretizing the geometry of the target part/structure into node points and calculating the risk angles numerically by iterating a particular algorithm over each node *** improved efficiency and excellent accuracy for the developed algorithm was validated through a comparison with manual solutions for the hazard quantification of the engine nacelle structures of a passenger aircraft using the guidance in *** further demonstrate the applicability of the boundary discretization method,the proposed algorithm was used to examine the influence of the target size and the distance between the target and rotor on the hazard probability.

关键词： Boundary discretization Critical point Hazard probability Risk angle Uncontained engine rotor failure

Mechanical behaviors of polycrystalline NiTi SMAs of various grain sizes under impact loading

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Science China(Technological Sciences) 2021年第7期64卷 1401-1411页

作者： XIAO Rui HOU Bing SUN QingPing ZHAO Han li yulong School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Departement of Mechanical and Aerospace Engineering the Hong Kong University of Science and TechnologyHong Kong999077China Laboratoire de Mécanique et Technologie Cachan cedex94235France Sorbonne Université Paris75272France

This work presents mechanical properties of the NiTi polycrystalline superelastic shape memory alloys(SMA) of 5 different grain sizes under high-speed impacts. The amorphous, nanocrystalline(40, 80, 120 nm) and coarse grain(20 μm) sheets are manufactured with cold rolling and suitable heat treatments. A Hopkinson tensile bar is used to perform tests up to 45 m/s. Highspeed camera system and digital image correlation method are used to get the strain field and particle velocity field at a sampling frequency of 2×10~6 frames/s with a resolution of 924×768 pixels. Nominal stress-strain curves are obtained for all the sheets with a strain rate of about 1000 s~(-1) and they have a similar evolution to the quasi-static case but with much higher stress levels. The rate sensitivity is increased with the grain size and the stress level can reach up to a 70% growth for a coarse grain sheet but be totally insensitive for the amorphous sheet in the strain rate from 10~(-4) to 10~3 s~(-1). A single transformation front can be found under high-speed impact(45 m/s) at the early loading stage. The speed of the transformation front is calculated from strain time histories and the highest front speed of 811 m/s is observed which is never observed before. It also reveals that the front speed depends also on the grain size. With the same loading speed, the bigger the grain size is, the slower the transformation front speed is.

关键词： NiTi shape memory alloys mechanical property rate sensitivity phase transformation grain size effects

Temperature Effect on the Mechanical Behavior of Acrylic Polymers under Quasi-static and Dynamic Loading

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上海交通大学学报 2004年第z2期38卷 89-95页

作者： Tao Suo yulong li Hong Yu Fei Xu Zhongbin Tang Lei li School of Aeronautics Northwestern Polytechnical University Xi''an710072 China School of Aeronautics Northwestern Polytechnical University Xi''an710072 China School of Aeronautics Northwestern Polytechnical University Xi''an710072 China School of Aeronautics Northwestern Polytechnical University Xi''an710072 China School of Aeronautics Northwestern Polytechnical University Xi''an710072 China Beijing Institute of Aeronautical Materials Beijing100095China

In this paper, the mechanical behavior of acrylic polymers at elevated temperature was investigated. Four acrylic polymers were tested at high strain rate by using compression Hopkinson bar and at quasi-static strain rate by using an Instron servo hydraulic axial testing machine with the testing temperature from 218K to 393K. The results show that the mechanical property of acrylic polymers depends heavily on the testing temperature. The yield stress and Young's modulus were found to decrease with increasing temperature at low strain rate. At very low temperature, the materials display typical brittle fracture; however their plasticity improves remarkably at high temperatures. The predictions of the mechanical behavior including the effect of temperature and strain rate using a proposed theoretical model have a good agreement with experimental results.

关键词： acrylic polymer compression Hopkinson bar quasi-static dynamic fracture