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Reconfigurable mechanism-based metamaterials for ternary-coded elastic wave polarizers and programmable refraction control

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1225-1242页

作者： Zhou HU Zhibo WEI Yan CHEN Rui ZHU School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081China School of mechanical Engineering Tianjin UniversityTianjin300350China Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin300350China

Elastic metamaterials with unusual elastic properties offer unprecedented ways to modulate the polarization and propagation of elastic ***,most of them rely on the resonant structural components,and thus are frequency-dependent and ***,we present a reconfigurable 2D mechanism-based metamaterial which possesses transformable and frequency-independent elastic *** on the proposed mechanism-based metamaterial,interesting functionalities,such as ternarycoded elastic wave polarizer and programmable refraction,are ***,unique ternary-coded polarizers,with 1-trit polarization filtering and 2-trit polarization separating of longitudinal and transverse waves,are first ***,the strong anisotropy of the proposed metamaterial is harnessed to realize positive-negative bi-refraction,only-positive refraction,and only-negative ***,the wave functions with detailed microstructures are numerically verified.

关键词： elastic metamaterial elastic wave reconfigurable design zero mode ternary code programmable refraction

Enabling the transfer matrix method to model serial-parallel compliant mechanisms including curved flexure beams

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International Journal of mechanical System Dynamics 2024年第1期4卷 48-62页

作者： Mingxiang Ling Lei Yuan Tingjun Zeng Xianmin Zhang Robotics and Microsystems Center Soochow UniversitySoochowChina Guangdong Key Laboratory of Precision Equipment and Manufacturing Technology School of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhouChina

Compliant mechanisms with curved flexure hinges/beams have potential advantages of small spaces,low stress levels,and flexible design parameters,which have attracted considerable attention in precision engineering,metamaterials,robotics,and so ***,serial-parallel configurations with curved flexure hinges/beams often lead to a complicated parametric ***,the transfer matrix method is enabled for analysis of both the kinetostatics and dynamics of general serial-parallel compliant mechanisms without deriving laborious formulas or combining other modeling ***,serial-parallel compliant mechanisms with curved flexure hinges/beams can be modeled in a straightforward manner based on a single transfer matrix of Timoshenko straight beams using a step-by-step *** and numerical validations on two customized XY nanopositioners comprised of straight and corrugated flexure units confirm the concise modeling process and high prediction accuracy of the presented *** conclusion,the present study provides an enhanced transfer matrix modeling approach to streamline the kinetostatic and dynamic analyses of general serial-parallel compliant mechanisms and beam structures,including curved flexure hinges and irregular-shaped rigid bodies.

关键词： compliant mechanisms curved flexure beams transfer matrix method nanopositioner rigid-body dynamics

Research on embedded locally resonant metamaterials used for vibration attenuation of thin-walled workpieces in mirror milling

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Acta Mechanica Sinica 2024年第8期40卷 1-16页

作者： Bei Ding Wei Wang Juliang Xiao Zhiqiang Wu Cheng Liu School of mechanical Engineering Tianjin UniversityTianjin300350China Tianjin Key Laboratory of Nonlinear Dynamics and Control Tianjin300350China Key Laboratory of Modern Mechanisms and Equipment Design of the State Ministry of Education Tianjin UniversityTianjin300350China

The shell composed of large-scale parts is the essential component of mechanical structures in the aerospace,shipping,and railway *** workpieces are characterized by thin walls and weak rigidity,thus requiring an effective technology for high-performance ***,an embedded locally resonant metamaterial with double resonators is proposed and combined with the magnetic follow-up support technology to attenuate the vibration of thin-walled parts for the first *** band structures and parametric adjustment laws are systematically investigated and validated by analytical calculation and finite element method,which proves the proposed model is broadband,lightweight,and flexible in low *** characteristics,as well as the relatively simple structure,are unique advantages for thin-walled structure ***,mirror milling experiments have been performed to assess the slave module with the proposed *** the results,the root mean square amplitude of the thin-walled workpiece with the combined device decreases by nearly 9%,which means that the performance has been improved by the combined ***,this work provides an integrated and efficient solution for vibration suppression in thin-walled parts milling,which extends locally resonant metamaterials to practical engineering fields and helps to improve the status quo of mirror milling from the perspective of metamaterials.

关键词： Local resonance Band gap Thin-walled workpieces Vibration suppression

Digital light processing based multimaterial 3D printing:challenges,solutions and perspectives

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International Journal of Extreme Manufacturing 2024年第4期6卷 151-174页

作者： Jianxiang Cheng Shouyi Yu Rong Wang Qi Ge Shenzhen Key Laboratory of Soft Mechanics&Smart Manufacturing Southern University of Science and TechnologyShenzhen 518055People's Republic of China Department of mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055People's Republic of China

Multimaterial(MM)3D printing shows great potential for application in metamaterials,flexible electronics,biomedical devices and robots,since it can seamlessly integrate distinctive materials into one printed *** numerous MM 3D printing technologies,digital light processing(DLP)MM 3D printing is compatible with a wide range of materials from hydrogels to ceramics,and can print MM 3D structures with high resolution,high complexity and fast *** paper introduces the fundamental mechanisms of DLP 3D printing,and reviews the recent advances of DLP MM 3D printing technologies with emphasis on material switching methods and material contamination *** also summarizes a number of typical examples of DLP MM 3D printing systems developed in the past decade,and introduces their system structures,working principles,material switching methods,residual resin removal methods,printing steps,as well as the representative structures and ***,we provide perspectives on the directions of the further development of DLP MM 3D printing technology.

关键词： multimaterial 3D printing digital lightprocessing multimaterial 3Dstructures

A concave photonic crystal waveguide with a corrugated surface for high-quality focusing

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Chinese Optics Letters 2011年第1期9卷 56-59页

作者：武红蒋立勇李海鹏贾巍郑改革强海霞李相银 Department of Physics Nanjing University of Science and Technology Nanoscale Technology and Engineering Laboratory Department of Mechanical EngineeringSchulich School of EngineeringUniversity of Calgary Tanaka metamaterials Laboratory

A concave two-dimensional （2D） photonic crystal waveguide （PCW） with corrugated surface is theoret- ically used as a focusing structure. To design this structure, a genetic algorithm is combined with the finite-difference time-domain method. For PCWs with different degrees of concaveness, the power reaches about 80% at different focusing points when the morphology of the concave surface is optimized. More importantly, the focusing location is easily controlled by changing the location of the detector placed in the outout field.

关键词： Crystal structure Finite difference time domain method Focusing Optical waveguides Photonic crystals Surface morphology Waveguides

mechanical Janus lattice with plug-switch orientation

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Theoretical & Applied Mechanics Letters 2024年第1期14卷 23-26页

作者： Yupei Zhang Jiawei Zhong Zhengcai Zhao Ruiyu Bai Yanqi Yin Yang Yu Bo Li State Key Laboratory for Manufacturing System EngineeringShaanxi Key Laboratory of Intelligent Robots School of mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China Qian Xuesen Honors College Xi’an Jiaotong UniversityXi’an 710049China

In recent years,materials with asymmetric mechanical response properties(mechanical Janus materials)have been found possess numerous potential applications,*** absorption and vibration *** this study,we propose a novel mechanical Janus lattice whose asymmetric mechanical response can be switched in orientation by a *** finite element analysis and experimental verification,this lattice exhibits asymmetric displacement responses to symmetric ***,with such a plug structure inside,individual lattices can switch the orientation of asymmetry and thus achieve reprogrammable design of a mechanical structure with chained *** reprogrammable asymmetry of this material will offer multiple functions in design of mechanical metamaterials.

关键词： Janus Non-reciprocity Programmability mechanical metamaterial

Hydrothermal and entropy generation specifications of a hybrid ferronanofluid in microchannel heat sink embedded in CPUs

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Chinese Journal of Chemical Engineering 2021年第4期34卷 27-38页

作者： Amin Shahsavar Majid Jafari Pouyan Talebizadehsardari Davood Toghraie Department of mechanical Engineering Kermanshah University of TechnologyKermanshahIran metamaterials for mechanical Biomechanical and Multiphysical Applications Research GroupTon Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Applied Sciences Ton Duc Thang UniversityHo Chi Minh CityVietnam Department of mechanical Engineering Khomeinishahr BranchIslamic Azad UniversityKhomeinishahrIran

The objective of this numerical work is to evaluate the first law and second law performances of a hybrid nanofluid flowing through a liquidcooled microchannel *** waterbased hybrid nanofluid includes the Fe_(3)O_(4)and carbon nanotubes(CNTs)*** heatsink includes a microchannel configuration for the flow field to gain heat from a processor placed on the bottom of the *** effects of Fe_(3)O_(4)concentration(φFe_(3)O_(4))>CNT concentration(φCNT)and Reynolds number(Re)on the convective heat transfer coefficient,CPU surface temperature,thermal resistance,pumping power,as well as the rate of entropy generation due to the heat transfer and fluid friction is *** results indicated higher values of convective heat transfer coefficient,pumping power,and frictional entropy generation rate for higher values of Re,Fe_(3)O_(4)andφ*** increasing Re,Fe_(3)O_(4)and uCNT,the CPU surface temperature and the thermal resistance decrease,and the temperature distribution at the CPU surface became more *** achieve the maximum performance of the studied heatsink,applying the hybrid nanofluid with low Fe_(3)O_(4)andφCNT was suggested,while the minimum entropy generation was achieved with the application of nanofluid with highφFe_(3)O_(4)andφCNT.

关键词： Liquid-cooled heatsink Hydrothermal aspects Irreversibility Hybrid nanofluid Carbon nanotube Fe_(3)O_(4)

Novel Lightweight and Protective Battery System Based on mechanical metamaterials

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Acta Mechanica Solida Sinica 2021年第6期34卷 862-871页

作者： Yao Huang Weihua Guo Jiao Jia Lubing Wang Sha Yin Vehicle Energy and Safety Laboratory(VESL) Department of Automotive EngineeringSchool of Transportation Science and EngineeringBeihang UniversityBeijing100191China Institute of Unmanned System Beihang UniversityBeijing100191China Key Laboratory Impact and Safety Engineering Ministry of Education and Department of Mechanics and Engineering ScienceFaculty of Mechanical Engineering and MechanicsNingbo UniversityNingbo315211ZhejiangChina

The challenges facing electric vehicles with respect to driving range and safety make the design of a lightweight and safe battery pack a critical *** study proposes a multifunctional structural battery system comprising cylindrical battery cells and a surrounding lightweight lattice *** lattice density distribution was optimized via topological optimization to minimize stress on the battery during *** a single 18650 cylindrical battery cell,non-uniform lattices were designed featuring areas of increased density in an X-shaped pattern and then fabricated by additive manufacturing using stainless steel *** testing of the assembled structural battery system revealed that the stronger lattice units in the X-shaped lattice pattern resisted deformation and helped delay the emergence of a battery short ***,the short circuit of the structural battery based on a variable-density patterned lattice was∼166%later than that with a uniform-density *** element simulation results for structural battery systems comprising nine battery cells indicate that superior battery protection is achieved in specially packed batteries via non-uniform lattices with an interconnected network of stronger *** proposed structural battery systems featuring non-uniform lattices will shed light on the next generation of lightweight and impact-resistant electric vehicle designs.

关键词： Lightweight Lattices metamaterials Structural battery Battery safety Internal short circuit

Auxetic mechanical metamaterials: from soft to stiff

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International Journal of Extreme Manufacturing 2023年第4期5卷 60-85页

作者： Xiang Li Weitao Peng Wenwang Wu Jian Xiong Yang Lu School of Sciences Nanjing University of Science and TechnologyNanjing 210094People’s Republic of China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Center for Composite Materials and Structures Harbin Institute of TechnologyHarbin 150001People’s Republic of China Nano-Manufacturing Laboratory(NML) CityU-Xidian Joint Laboratory of Micro/NanoManufacturingShenzhen Research Institute City University of Hong KongShenzhen 518057People’s Republic of China Department of mechanical Engineering City University of Hong KongKowloonHong Kong Special Administrative Region of ChinaPeople’s Republic of China Chengdu Research Institute City University of Hong KongChengdu 610200People’s Republic of China Department of mechanical Engineering The University of Hong KongPokfulamHong Kong Special Administrative Region of ChinaPeople’s Republic of China

Auxetic mechanical metamaterials are artificially architected materials that possess negative Poisson’s ratio,demonstrating transversal contracting deformation under external vertical compression *** physical properties are mainly determined by spatial topological ***,classical auxetic mechanical metamaterials exhibit relatively lower mechanical stiffness,compared to classic stretching dominated ***,in recent years,several novel auxetic mechanical metamaterials with high stiffness have been designed and proposed for energy absorption,load-bearing,and thermal-mechanical coupling *** this paper,mechanical design methods for designing auxetic structures with soft and stiff mechanical behavior are summarized and *** soft auxetic mechanical metamaterials,classic methods,such as using soft basic material,hierarchical design,tensile braided design,and curved ribs,are *** comparison,for stiff auxetic mechanical metamaterials,design schemes,such as hard base material,hierarchical design,composite design,and adding additional load-bearing ribs,are ***-functional applications of soft and stiff auxetic mechanical metamaterials are then *** hope this study could provide some guidelines for designing programmed auxetics with specified mechanical stiffness and deformation abilities according to demand.

关键词： auxetic mechanical metamaterial soft stiff structural design