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High-static-low-dynamic stiffness isolator based on an electromagnetic negative stiffness spring with long linear stroke

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Science China(Technological Sciences) 2024年第3期67卷 740-752页

作者： YUAN ShuJin WU YaJun SONG DaiPing PU HuaYan MOU LiSheng HOU Lei ZHAO JingLei LI XuePing LUO Jun WU Jie huang xiaoxu State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China China Aerodynamics Research and Development Center Mianyang 621000China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

Negative stiffness mechanisms can improve low-frequency vibration isolation performance and have been widely used in the vibration isolation of precision equipment. However, the negative stiffness mechanism usually introduces a nonlinear stiffness,resulting in a nonlinear response and worsening the vibration isolation performance, especially under large amplitude *** this paper, an electromagnetic spring with linear negative stiffness(ESLNS) is proposed, in which the antagonistic ampere forces of the energized coils are used to generate negative stiffness within a long linear stroke. The magnetic field distribution is improved through the design of the magnetic circuit, thereby increasing the stiffness generation efficiency. The stiffness can be adjusted bidirectionally by current within the range of positive and negative stiffness. An electromagnetic stiffness model was established based on the equivalent magnetic circuit method. Experimental measurements verified the accuracy of the model and proved the linearity of the electromagnetic spring. A vibration isolator with high static and low dynamic stiffness(HSLDS) based on the ESLNS is designed and tested. The experimental results prove that the introduction of the ESLNS can effectively expand the isolation frequency band without changing the equilibrium position. Moreover, the vibration isolator with ESLNS does not produce nonlinear response. The proposed electromagnetic spring with linear negative stiffness extends the application range of HSLDS isolators to a large amplitude vibration environment.

关键词： linear negative stiffness mechanism low-frequency vibration isolation electromagnetic spring vibration control

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Exceptionally high strain hardening via two-dimensional atomic scale faulting

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Science China Materials 2023年第12期66卷 4897-4898页

作者： Andrew Godfrey xiaoxu huang Laboratory of Advanced Materials School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China International Joint Laboratory for Light Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400044China

Strain hardening is a characteristic and important property of metals whereby they are strengthened by the introduction of lattice defects during plastic *** general,a high strain hardening ability is desired,both to ensure the safety of metal components under load and to enable high ductility,allowing the formation of complex *** underlying mechanisms of strain hardening have been extensively studied and are related to an increase in the density of linear lattice defects,i.e.,dislocations,and to the interaction between these defects during the evolution of three-dimensional dislocation structures[1±3].Coarse-grained(CG)metals generally show the highest strain hardening and the best tensile ductility due to the more abundant space for storage of dislocations in various forms of patterning.

关键词： strain ductility dimensional

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APPLICATION OF SURROGATE BASED PARTICLE SWARM OPTIMIZATION TO THE RELIABILITY-BASED ROBUST DESIGN OF COMPOSITE PRESSURE VESSELS

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Acta Mechanica Solida Sinica 2013年第5期26卷 480-490页

作者： Jianqiao Chen Yuanfu Tang xiaoxu huang Department of Mechanics Hubei Key Laboratory of Engineering Structural Analysis and Safety AssessmentHuazhong University of Science and Technology

A surrogate based particle swarm optimization （SBPSO） algorithm which combines the surrogate modeling technique and particle swarm optimization is applied to the reliability- based robust design （RBRD） of composite pressure vessels. The algorithm and efficiency of SBPSO are displayed through numerical examples. A model for filament-wound composite pressure vessels with metallic liner is then studied by netting analysis and its responses are analyzed by using Finite element method （performed by software ANSYS）. An optimization problem for maximizing the performance factor is formulated by choosing the winding orientation of the helical plies in the cylindrical portion, the thickness of metal liner and the drop off region size as the design variables. Strength constraints for composite layers and the metal liner are constructed by using Tsai-Wu failure criterion and Mises failure criterion respectively. Numerical examples show that the method proposed can effectively solve the RBRD problem, and the optimal results of the proposed model can satisfy certain reliability requirement and have the robustness to the fluctuation of design variables.

关键词： structural optimization reliability based robust design composite pressure vessel,surrogate based particle swarm optimization sequential algorithm

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Editorial for a special issue on nanostructured metals and alloys

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Nano Materials Science 2020年第1期2卷 1-2页

作者： xiaoxu huang Chongqing University PR China

Nanostructured metals and alloys are a versatile family of metallic materials that possess various excellent properties and offer the potential for a diverse range of industrial and biomedical *** over more than two decades in this field has achieved tremendous progress in processing,characterization,and microstructural design,as well as fundamental understanding,and *** recent years.

关键词： Editorial issue field

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咖啡酸味特性研究进展

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热带农业科技 2024年第1期47卷 23-27页

作者：黄晓旭张勇夏斌普洱市茶叶和咖啡产业发展中心云南普洱665000 普洱市农业科学研究所云南普洱665000

咖啡的酸味可直接影响咖啡品质和消费者对咖啡的接受度,影响咖啡酸味的因素有产区、品种、初加工方式、烘焙、冲泡和储藏等,目前咖啡酸味物质的鉴定主要采用理化仪器分析与感官分析相结合。文章归纳了咖啡酸味物质的种类、影响因素、测... 详细信息

咖啡的酸味可直接影响咖啡品质和消费者对咖啡的接受度,影响咖啡酸味的因素有产区、品种、初加工方式、烘焙、冲泡和储藏等,目前咖啡酸味物质的鉴定主要采用理化仪器分析与感官分析相结合。文章归纳了咖啡酸味物质的种类、影响因素、测定方法及酸味对咖啡偏好度产生的影响,为从业者开展咖啡产品质量控制及烘焙工艺提升提供参考。

关键词：咖啡酸味物质影响因素鉴定方法

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案例教学法在房屋建筑学课程中的应用探索

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科教导刊 2024年第14期 122-124页

作者：黄晓旭胡彪蒋嘉嘉深圳大学土木与交通工程学院广东深圳518060

文章分析了目前房屋建筑学课程的教学特点与现状,介绍了案例教学法的概念及特色,并从理论及实践层面开展了案例教学法应用于房屋建筑学课程教学的探索。案例教学法的应用有效调动了学生学习的主动性,改善了教学效果,深化了学生对房屋建... 详细信息

文章分析了目前房屋建筑学课程的教学特点与现状,介绍了案例教学法的概念及特色,并从理论及实践层面开展了案例教学法应用于房屋建筑学课程教学的探索。案例教学法的应用有效调动了学生学习的主动性,改善了教学效果,深化了学生对房屋建筑学知识点与内涵的认知。同时,提高了学生独立思考、团队合作以及理论联系实际的能力,本文研究成果有望为后续相关专业课程教学提供新思路和新方法。

关键词：案例教学法房屋建筑学土木工程教学效果

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卡前列甲酯栓联合缩宫素预防剖宫产产后出血的应用研究

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临床医学工程 2024年第5期31卷 575-576页

作者：杨清云王琳黄小栩洛阳市第六人民医院妇产科河南洛阳471000

目的探讨卡前列酯栓联合缩宫素在预防剖宫产产后出血中的效果。方法选择2021年5月至2022年11月于我院行剖宫产的产妇80例,随机分为两组各40例。对照组采用缩宫素,观察组采用卡前列酯栓联合缩宫素治疗。对比两组的产后出血情况、凝血指... 详细信息

目的探讨卡前列酯栓联合缩宫素在预防剖宫产产后出血中的效果。方法选择2021年5月至2022年11月于我院行剖宫产的产妇80例,随机分为两组各40例。对照组采用缩宫素,观察组采用卡前列酯栓联合缩宫素治疗。对比两组的产后出血情况、凝血指标及不良反应。结果观察组产后大出血发生率为5.00%,低于对照组的20.00%(P0.05)。结论卡前列甲酯栓联合缩宫素预防剖宫产产后出血能够降低产后大出血发生率,减少产后出血量,改善凝血功能,安全性较高。

关键词：剖宫产卡前列甲酯栓缩宫素产后出血凝血指标不良反应

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Fused structures for safer and more economical constructions

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Frontiers of Structural and Civil Engineering 2020年第1期14卷 1-9页

作者： Yu-Fei WU Ying-Wu ZHOU Biao HU xiaoxu huang Scott SMITH School of Engineering RMIT UniversityMelbourneVIC 3001Australia Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering Shenzhen UniversityShenzhen 518061China School of Civil Environmental and Mining EngineeringThe University of AdelaideSouth Australia 5005Australia

Safety margin and construction costs are two conflicting goals for a *** providing a fuse in a structure that is triggered at a certain level of over-loading,further increase of loading is prohibited and failure of the structure is changed to a safer *** overloading is controlled and a safer failure mode is enforced,a fused structure requires a smaller safety factor thus leading to more economical construction without compromising *** use of a fuse will also facilitate safer use of advanced construction materials such as fiber-reinforced polymer(FRP)*** this case,a fuse can transfer the sudden and dangerous failure mode associated with brittle FRP debonding or rupture to a safe and ductile failure mode at the fuse *** paper introduces a new type of fused structure as well as an associated design philosophy and approach,in addition to examples of engineering applications.

关键词： fused structures structural fuse fiber-reinforced polymer concrete

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Laminated Fe-34.5 Mn-0.04C composite with high strength and ductility

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Journal of Materials Science & Technology 2018年第10期34卷 1939-1943页

作者： Yuhui Wang Jianmei Kang Yan Peng Tiansheng Wang Niels Hansen xiaoxu huang State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 China National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan University Qinhuangdao 066004 China Riso Campus Technical University of Denmark DK-4000 Roskilde Denmark College of Materials Sdence and Engineering Chongqing University Chongqing 400045 China Department of Mechanical Engneering Technical University of'Denmark DK-2800 Lyngby Denmark

To obtain a good combination of strength and ductility, a laminated composite structure composed of recovered hard lamellae and soft recrystallized lamellae has been produced in a single phase austenitic Fe-34.5 Mn-0.04C steel by cold rolling and partial recrystallization. Enhanced mechanical properties in both strength and ductility have been obtained in the composite structure compared to a fully recrystallized coarse grain structure. A further increase in strength with only minor loss in total elongation has been achieved by a slight cold rolling of the composite structure, which also removes the small yield drop and Luders elongation observed in the composite structure.

关键词： Laminated composite structure Partial recrystallization Constraint effect Strength Ductility

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2D and 3D orientation mapping in nanostructured metals: A review

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Nano Materials Science 2020年第1期2卷 50-57页

作者： Guilin Wu Wanquan Zhu Qiongyao He Zongqiang Feng Tianlin huang Ling Zhang SØren Schmidt Andrew Godfrey xiaoxu huang International Joint Laboratory for Light Alloys(MOE) College of Materials Science and EngineeringChongqing UniversityChongqing400044China Shenyang National Laboratory for Materials Sciences Chongqing UniversityChongqing400044China Electron Microscopy Center of Chongqing University Chongqing UniversityChongqing400044China Department of Physics Technical University of DenmarkDK-2800 KgsLyngbyDenmark Laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing100184China

Nanostructured metals possess various excellent properties and offer the potential for a wide range of *** in the properties and performance of nanostructured metal components motivate a complete characterization of the microstructures and crystallographic orientations of nanostructured metals with nanoscale spatial *** well developed orientation mapping techniques for such characterization are electron backscatter diffraction(EBSD)in the scanning electron microscope and precession electron diffraction(PED)using diffraction spots in the transmission electron ***,these methods can only characterize the structure in two *** is still a great challenge to characterize grains in three dimensions,*** the interior of the nanostructured ***,three-dimensional orientation mapping in the transmission electron microscope(3 D-OMi TEM)was developed and further improvements of this technique are introduced in this *** of these orientation mapping techniques for structural and orientational characterizations are demonstrated by examples of surface-deformed metals with gradient nanostructures,and a sputtered gold film of nano-islands containing *** merits and challenges of each of these techniques are discussed and suggestions for further developments are proposed.

关键词： Nanostructured metals Microstructure Crystallographic orientation EBSD PED 3D-OMiTEM

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