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Multi-layer quasi-zero-stiffness meta-structure for high-efficiency vibration isolation at low frequency

Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1189-1208页

作者： Jiahao ZHOU Jiaxi ZHOU Hongbin PAN Kai WANG Changqi CAI Guilin WEN College of Mechanical and Vehicle Engineering Hunan UniversityChangsha410082China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body The Ministry of Science and TechnologyChangsha410082China School of Mechanical Engineering Zhejiang Sci-Tech UniversityHangzhou310018China School of Mechanical Engineering Yanshan UniversityQinhuangdao066004Hebei ProvinceChina

An easily stackable multi-layer quasi-zero-stiffness(ML-QZS)meta-structure is proposed to achieve highly efficient vibration isolation performance at low ***,the distributed shape optimization method is used to design the unit cel,i.e.,the single-layer QZS(SL-QZS)***,the stiffness feature of the unit cell is investigated and verified through static ***,the unit cells are stacked one by one along the direction of vibration isolation,and thus the ML-QZS meta-structure is ***,the dynamic modeling of the ML-QZS vibration isolation metastructure is conducted,and the dynamic responses are obtained from the equations of motion,and verified by finite element(FE)***,a prototype of the ML-QZS vibration isolation meta-structure is fabricated by additive manufacturing,and the vibration isolation performance is evaluated *** results show that the vibration isolation performance substantially enhances when the number of unit cells *** importantly,the ML-QZS meta-structure can be easily extended in the direction of vibration isolation when the unit cells are properly ***,the ML-FQZS vibration isolation meta-structure should be a fascinating solution for highly efficient vibration isolation performance at low frequency.

关键词： quasi-zero stiffness(QZS) meta-structure high efficiency low frequency vibration isolation

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An architecture decomposition method of pneumatic catapult system based on OPM and DSM

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Chinese Journal of Aeronautics 2023年第8期36卷 168-181页

作者： Lu GAN Gang YANG Xianhui LI Enze ZHU Hu CHEN Xiaohui WEI State Key Laboratory of Mechanics and Control of Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of General Aviation and Flight Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The architecture strategy of the Unmanned Aerial Vehicle(UAV)pneumatic launch system should continue to evolve to adapt to complex and variable operating *** representation,decomposition perspective,and cluster analysis play a vital role in the early phase of system architecture *** order for the system to emerge anticipated and desirable intrinsic functional properties,an architecture decomposition method based on the ObjectProcess Methodology(OPM)and design Structure Matrix(DSM)is put forward in this *** OPM is proposed to model the UAV launch process formally,and the matrix representation of the architecture of the pneumatic launch system is *** the extension of the definition and operations of DSM,with the Idicula-Gutierrez-Thebeau Algorithm plus(IGTA+)clustering algorithm,the transformation of the pneumatic launch system architecture from process decomposition to function decomposition is demonstrated in this *** analysis shows that the architecture decomposition of the pneumatic launch system meets the functional requirements of stakeholders.

关键词： Architecture decomposition Cluster analysis design structure matrix Object-process methodology Pneumatic catapult system

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Erosion characteristics of dual cavitating waterjet under an unsubmerged environment

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PHYSICS OF FLUIDS 2025年第2期37卷

作者： [Anonymous] Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan University Wuhan 430072 China Nanjing Chenguang Group China Aerospace Science & Industry Nanjing 210001 China Training Base of Army Engineering University of PLA Xuzhou 221000 China Wuhan Second Ship Design and Research Institute Wuhan 430205 China

To improve the erosion performance of cavitating waterjet under an unsubmerged environment, dual cavitating waterjet, which is created by generating shear cavitation and separation cavitation in the jet beam, was first proposed in this study. The shear cavitation was produced by concentric high-speed and low-speed waterjets, and the separation cavitation was generated by an embedded central body. The morphology characteristics of the erosion region and the effects of non-dimension standoff distance (NSD), high-speed waterjet pressure (P-H), and low-speed nozzle diameter (d(L)) on the erosion characteristics of pure aluminum Al1060 specimens impacted by the dual cavitating waterjet were investigated. The flow field at the nozzle outlet was also numerically studied. The results show that the erosion region is typically circular in shape and mainly composed of 3 parts, which are the center hole, the low damage region, and the shear cavitation ring. The center hole is always much deeper than the shear cavitation ring. The mass loss of the specimen first increases and then decreases with the increase in NSD. The waterjet has a better erosion effect when the P-H increases, and the peripheral low-speed waterjet has a better effect on the artificial submerged environment when d(L) = 20 mm. The maximum mass loss is 58.1 mg at NSD of 14 when P-H is 30 MPa and d(L) is 20 mm. This study provides a new type of waterjet generating effective cavitation under an unsubmerged environment, which could promote the applications of a cavitating waterjet.

关键词： Nozzles

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Magnetic and magnetocaloric effect in a stuffed honeycomb polycrystalline antiferromagnet GdInO_(3)

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Chinese Physics B 2022年第6期31卷 656-662页

作者： Yao-Dong Wu Wei-Wei Duan Qiu-Yue Li Yong-Liang Qin Zhen-Fa Zi Jin Tang Universities Joint Key Laboratory of Photoelectric Detection Science and Technology in Anhui Province Anhui Province Key Laboratory of Simulation and Design for Electronic Information Systemand School of Physics and Materials EngineeringHefei Normal UniversityHefei 230601China Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field LaboratoryHFIPSAnhuiChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China

The magnetic and magnetocaloric properties were studied in a stuffed honeycomb polycrystalline antiferromagnet GdInO_(3).The onset temperature of antiferromagnetic ordering was observed at~2.1 *** thermal and magnetic hystereses suggest a reversible magnetocaloric effect(MCE)in the GdInO_(3) *** the magnetic field changes of 0 kOe-50 kOe and 0 kOe-70 kOe,the maximum magnetic entropy change values are 9.65 J/kg·K and 18.37 J/kg·K,respectively,near the liquid helium temperature,with the corresponding relative cooling power values of 115.01 J/kg and211.31 J/*** MCE investigation of the polycrystalline GdInO_(3) serves to illuminate more exotic properties in this frustrated stuffed honeycomb magnetic system.

关键词： GdInO_(3) magnetization magnetocaloric effects stuffed honeycomb antiferromagnet

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Theoretical dissection of the electronic anisotropy and quantum transport of ultrascaled halogenated borophene MOSFETs

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Physical Review Applied 2024年第5期21卷 054016-054016页

作者： Shiying Guo Ying Wang Hengze Qu Wenhan Zhou Yee Sin Ang Shengli Zhang Haibo Zeng College of Physics Science and Technology Yangzhou University Yangzhou 225002 China MIIT Key Laboratory of Advanced Display Materials and Devices School of Materials Science and Engineering Nanjing University of Science and Technology Nanjing 210094 China Science Mathematics and Technology Singapore University of Technology and Design Singapore 487372 Singapore

Two-dimensional (2D) anisotropic semiconductors, such as black phosphorene, show strong potential in ultrascaled metal-oxide-semiconductor field-effect transistors (MOSFETs) as the anisotropic electronic structure is highly beneficial in boosting the device performance at sub-10-nm gate length regime. Metallic graphenelike borophene can be halogenated to form a stable monolayer family of B4X4 (X = F,Cl,andBr) whose highly anisotropic semiconducting electronic structures suggest a potential in ultrascaled MOSFET applications. Here, we computationally explore the quantum transport properties of B4X4 monolayers as high-performance (HP) 5-nm MOSFETs. The HP on-state current of the n-type 5-nm monolayer B4X4 MOSFETs can reach over 3000 µA/µm at 5-nm gate length regime, thus fulfilling the ITRS requirement of HP devices. Of note, by analyzing the physical relationship between the anisotropic electronic structures (transport effective mass m// and density of states mDOS), we show that large electronic anisotropy does not immediately guarantee high performance. An overly large m// or mDOS would suppress the saturation current and lead to limited HP on-state current of monolayer B4X4, thus revealing a balance between the effective masses is needed when designing 2D semiconductor MOSFETs. This work provides insights and design guidelines for the development of next-generation nanoelectronic devices based on the exceptional transport properties of 2D anisotropic channel materials.

关键词： Ballistic transport Electronic structure Quantum transport 2-dimensional systems MOSFET Semiconductor compounds Density functional calculations Nonequilibrium Green's function

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Effects of irradiation dose and temperature on dislocation loop evolution of Al-forming austenitic stainless steel with In-situ TEM observation

Effects of irradiation dose and temperature on dislocation l...

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2022 International Conference on Optoelectronic Information and Functional Materials, OIFM 2022

作者： Ma, Zhaodandan Zhang, Ruiqian Wu, Jun Chen, Huan Shu, Ming Science and Technology on Reactor Fuel and Materials Laboratory Chengdu610041 China Nuclear Power Institute of China Chengdu610041 China

ISBN: (数字)9781510655126

ISBN: (纸本)9781510655119

The Al-forming austenitic (AFA) stainless steel are regarded as an excellent potential candidate for next generation nuclear reactor. But the irradiation effects on its microstructural and mechanical properties are still unclear. In this paper, irradiations with a 400KeV Fe+ accelerator at room temperature (RT), 673 K and 773 K were produced. Self-ions were selected to study the evolution of irradiated-induced dislocation loops singly avoiding an interaction with other irradiation defects. The loop nature, average size and density were affected obviously by irradiation dose and temperature. Two sets of dislocation loops were identified to b = 1/2 © 2022 SPIE.

关键词： Austenitic stainless steel

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Research on Fluctuation Attenuation and Optimization of Passive Residual Heat Removal System Based on Spring Vibrator

SSRN

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SSRN 2024年

作者： Kang, Zehang Wang, Sipeng Du, Peng Chen, Jin Su, Zhen Zhuang, Kun Department of Nuclear Science and Technology Nanjing University of Aeronautics and Astronautics JiangSu Nanjing211106 China Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautics Nanjing University of Aeronautics and Astronautics China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The potential for flow instability in passive residual heat removal systems (PRHRS) to result in equipment damage underscored the necessity for the development of effective mitigation strategies. In order to reduce the flow instabilities that occurs in the PRHRS, the idea of a fluctuation attenuation scheme based on a spring vibrator structure had been proposed. The structure was based on pressure pulsation attenuator in hydraulic systems and had been optimized. A model of a spring vibrator fluctuation attenuation pipe section was developed and its fluctuation attenuation effect was verified under specific parameters. Such as branch pipe length, cavity cross-sectional area, spring vibrator position, spring vibrator stiffness coefficient, and piston mass. The impact of these factors on fluctuation attenuation was investigated. The results demonstrated that, under identical inlet fluctuation conditions, the fluctuation peak at outlet of the pipe containing spring vibrator structure decreased. The optimization of the above parameters had been demonstrated to enhance the fluctuation removal effect of the spring vibrator structure. This study presented a novel approach to relieve flow instability in PRHRS. © 2024, The Authors. All rights reserved.

关键词： Vibrators

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Biopolymer-Based Aerogels for Electromagnetic Wave Shielding and Absorbing

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Chinese Journal of Chemistry 2023年第3期41卷 322-334页

作者： Mingrui Han Runa Zhang Qilei Wu Na Wu Jiurong Liu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of Education and School of Materials Science and EngineeringShandong UniversityJinanShandong250061 China Science and Technology on Electromagnetic Compatibility Laboratory China Ship Development and Design CentreWuhanHubei430064 China Department of Chemistry and Applied Biosciences ETH ZurichCH-8093 ZurichSwitzerland

The rapid development of communication technology and electronic industry has brought unprecedented serious electromagnetic interference(EMI)and electromagnetic wave(EMW)*** EMI shields and EMW absorbers based on metal or magnetic materials were used to solve these problems,they have long been criticized for their high price,high density and easy *** order to achieve low density and efficient dissipation of electromagnetic energy,aerogels stand out among manifold ***,constructing aerogels with good EMI shielding or EMW absorption performance and acceptable mechanical properties is not an easy *** biopolymers,such as cellulose,lignin,chitin/chitosan and alginate,breathe new life into aerogels for high-efficiency EMW shielding and ***,we reviewed the contributions of biopolymers in the fields of aerogels for EMW shielding and *** the same time,some challenges and outlook were also pointed out,aiming to promote the advance of aerogel-based EMI shields and EMW absorbers as well as the rational utilization of biopolymers.

关键词： Polymers Sustainable chemistry Electromagnetic interference(EMI)shielding Electromagnetic wave(EMW)absorbing Biomass Aerogels Biopolymers

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Effect of Incoming Vortex on Secondary Flows in Turbine Cascades with Planar and Non-Axisymmetric Endwall

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Journal of Thermal science 2024年第1期33卷 138-157页

作者： CAO Zhiyuan WANG Chuxuan SONG Zhigao GAO Xi ZHAO Wei LIU Bo School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical UniversityXi'an 710072China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100080China School of Aeronautics and Astronautics University of Chinese Academy of SciencesBeijing 100080China

Non-Axisymmetric Endwall Profiling(NAEP) is commonly utilized in turbines to eliminate secondary ***,most of the NAEP methods consider a single-blade row environment without incorporating the effect of the stage *** paper aims to investigate the influence mechanism of the incoming vortex on the endwall secondary flow structures of NAEP in a highly loaded turbine *** model the incoming vortex in a stage environment,this study considers a half-delta wing as the vortex generator at the upstream of the turbine *** NAEP is then carried out for a highly loaded turbine cascade with an in-house numerical optimization design platform subject to no incoming *** simulation is also carried out under the influence of the incoming vortex for the turbine cascades with both planar and non-axisymmetric *** paper furthers investigated the pitchwise effect of the incoming vortex on the near endwall secondary *** results indicate that the NAEP effectively improves the endwall secondary flow of the turbine cascade,where the total pressure loss coefficient and the secondary kinetic energy(SKE) are reduced by 7.3%,and 45.7%,*** is further seen that with the incoming vortex,the NAEP achieves a considerable control effect on the endwall secondary flow of the turbine *** incoming vortex,the NAEP can still achieve considerable control effect on the endwall secondary flow of the turbine cascade;the averaged reductions of loss coefficient and SKE are 7.8% and 14.2%,*** some pitchwise locations,incoming vortex can suppress the convection of cross-passage flow toward the suction corner greatly and reduce the loss coefficient of the baseline *** incoming vortex at 4/7 pitch impinged right at the blade leading edge,leading to the generation of low-momentum fluid,which increased the size and the strength of the horseshoe *** all the pitchwise locations,NAEP can suppress the seco

关键词： non-axisymmetric endwall secondary flow incoming vortex passage vortex stage environment

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Fuzzy Adaptive Piecewise PI Control of a Flexible Traction Large Inertia Underwater Vehicle 33rd

Fuzzy Adaptive Piecewise PI Control of a Flexible Traction L...

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33rd International Ocean and Polar Engineering Conference, ISOPE 2023

作者： Wu, Hongming Xu, Guohua Shen, Xiong Li, Junwei Qiang, Sheng Underwater Technology Laboratory School of Naval Architecture and ocean Engineering Huazhong University of Science and Technology Wuhan 2ndShip Design and Research Institute Ocean Smart Technology Co. Ltd. Hubei Province Wuhan China

ISBN: (纸本)9781880653807

In this paper, the speed control strategy of a large inertia underwater vehicle with flexible cable traction is studied. The system consists of two winches directly driven by electric motors, two wire ropes and an underwater vehicle installed on a linear guide device. The model of the flexible traction underwater vehicle with dual direct drive motor system is established. The model incorporates the response characteristics of the motor-driven winch and the water resistance variation of the underwater vehicle. To achieve smooth speed control and reduce the vibration of cable tension, this paper proposes a Piecewise fuzzy adaptive PID control method. This control method can control the underwater vehicle to reach the target speed smoothly and quickly, and the oscillation amplitude of the traction force is small during the traction process. © 2023 by the International Society of Offshore and Polar Engineers (ISOPE).

关键词： Speed control

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