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Bio-inspired Filter design Based on Vortex Control Mechanism of Parallel Groove Structure

Journal of Bionic engineering 2023年第1期20卷 338-348页

作者： Yawei Zhu Dean Hu Yonggang Guo Hao Ding Gang Yang School of Mechanical and Electrical Engineering Henan University of TechnologyZhengzhou450001China Key Laboratory of Advanced Design and Simulation Techniques for Special Equipments Ministry of EducationHunan UniversityChangsha410082China

Solid–liquid separation is widely used in daily life and practical *** industrial filters are prone to clogging,but this rarely occurs in filter-feeding *** by the filter feeding mechanism of balaenid whales and considering the local grooves in the fringes layer,a new bionic filter is produced by 3D printing technology through the bionic design of the parallel channels inside the mouth of balaenid *** the same time,a test platform composed of the bionic filter,peristaltic pump,fluid pulse rectifier and water tank is built to carry out the fluid flow pattern dyeing and particle filtration *** is found that fluid separation occurs near the groove structure and local vortices are *** vortex control filtration mechanism makes the particles in the front grooves tend to accumulate on the left side,which has a certain anti-clogging ***,the increase of flow velocity leads to the enhancement of vortices,which makes the accumulation effect on the left more *** study initially practices the bionic application from biological model to engineering design,and the vortex control anti-clogging filtration mechanism proposed in the study has a wide range of application prospects and values.

关键词： Solid-liquid separation Balaenid whales Filter feeding-Bionic design Anti-clogging filtration mechanism

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Nonlinear electromechanical coupling dynamics of a two-degree-of-freedom hybrid energy harvester

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Applied Mathematics and Mechanics(English Edition) 2025年第6期46卷 989-1010页

作者： Tingting CHEN Kai WANG Shengchao CHEN Ziyu XU Zhe LI Jiaxi ZHOU College of Mechanical and Vehicle Engineering Hunan University Key Laboratory of Advanced Design and Simulation Techniques for Special Equipment Ministry of Education Hunan University

Vibration energy harvesting presents a significant opportunity for powering wireless sensor networks and internet of things(IoT) devices, offering a sustainable alternative to traditional battery-based power sources. However, environmental vibrations are predominantly low-frequency, which presents a significant challenge to the efficient conversion of such energy. To address this challenge, this paper proposes a novel twodegree-of-freedom(2-DOF) energy harvester. The first layer of the harvester incorporates a piezoelectric composite beam(PCB) paired with permanent magnets to form a negative stiffness mechanism(NSM), which counteracts the stiffness of linear springs, thereby achieving quasi-zero stiffness(QZS) or bistable characteristics. The second layer integrates piezoelectric transduction units with triboelectric nanogenerator(TENG) units to further enhance the efficiency of low-frequency vibration energy conversion. By considering the modal characteristics of the PCB, this paper establishes the electromechanical coupling equations of the harvester from an energy perspective. The mechanical responses of the masses in both layers, as well as the electrical outputs of the PCB, are analytically solved. Furthermore, the effects of the system parameters on the efficiency of low-frequency vibration energy harvesting are thoroughly analyzed. This work provides a theoretical foundation for the development of self-powered IoT sensor nodes, enabling efficient energy harvesting from ambient low-frequency vibrations.

关键词： energy harvesting low frequency O322 piezoelectric beam quasi-zero stiffness (QZS) triboelectric nanogenerator (TENG)

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Assessing the energy saving potential of using adaptive setpoint temperatures:The case study of a regional adaptive comfort model for Brazil in both the present and the future

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Building simulation 2024年第3期17卷 459-482页

作者： Daniel Sánchez-García David Bienvenido-Huertas Carlos Rubio-Bellido Ricardo Forgiarini Rupp Department of Electrical Engineering University Carlos III of MadridMadridSpain Department of Building Simulation ZEROCEM SLSevilleSpain Department of Building Constructions University of GranadaGranadaSpain Department of Building Constructions II University of SevilleSevilleSpain Section of Design for Sustainability Department of Civil and Mechanical EngineeringTechnical University of DenmarkKgs.LyngbyDenmark

It has been found in recent years that using setpoint temperatures based on adaptive thermal comfort models is a successful method of energy *** studies using adaptive setpoint temperatures incorporate international models from ASHRAE Standard 55 and *** study,however,has instead considered a regional Brazilian adaptive comfort *** study investigates the energy demand arising from the use of a local Brazilian comfort model in order to assess the energy implications from the use of the worldwide ASHRAE Standard 55 adaptive model and various fixed setpoint *** of Brazil’s climate zones,full air-conditioning,mixed-mode building operating modes,present-day climate change scenarios,and future scenarios—specifically Representative Concentration Pathways(RCP)2.6,4.5,and 8.5 for the years 2050 and 2100—have all been taken into account in building energy *** use of adaptive setpoint temperatures based on the Brazilian local model considering mixed-mode has been found to significantly reduce energy consumption when compared to static setpoint temperatures(average energy-saving values ranging from 52%to 58%)and the ASHRAE 55 adaptive model(average values ranging from 15%to 21%).Considering climate change and the mixed-mode Brazilian model,the overall energy demand for the three groups of climatic zones(annual average outdoor temperatures≤21℃,>21 and≤25℃and>25℃)ranged between 2%decrease and 5%increase,4%and 27%increase,and 13%and 45%increase,*** is concluded as a consequence that setting setpoint temperatures based on the Brazilian local adaptive comfort model is a very efficient energy-saving method.

关键词： adaptive thermal comfort building energy simulation energy efficiency climate change adaptive setpoint temperatures local comfort mode

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Modelling and Experimental Verification of the Internal Ballistics Trajectories in Gas Combustion Explosion Ejections 4

Modelling and Experimental Verification of the Internal Ball...

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4th International Conference on Defence Technology, ICDT 2024

作者： Ren, Jie Bi, Shuo Yao, Lin Lin, Guowen School of Mechanical Engineering Nanjing University of Science and Technology Nanjing China Nanjing Research Institute on Simulation Technique Nanjing China Beijing System Design Institute of Electro Mechanic Engineering Beijing China

The internal ballistic process and flow field were examined in the context of the launch of hydrogen-oxygen bipropellant explosives. This was achieved through the establishment of an internal ballistic launch model, which employed the high-low pressure launch principle. This approach diverges from the conventional tenets of internal ballistic theory, wherein a combustible gas is employed in lieu of a propellant for the purpose of launch. Furthermore, a high- low pressure chamber scheme was devised with the objective of mitigating the overload peaks that are typically encountered during the launch process. A fluid simulation was employed to conduct a virtual analysis of the flow field alterations within the high-low pressure chamber during the launch of a hydrogen-oxygen bipropellant explosive utilizing the internal ballistic model. The pressure variations over time within the high-low pressure chambers throughout the launch process were investigated, and the results were supplemented with load motion and physical ejection experiments. The results demonstrated that the simulated and calculated curves exhibited slight elevation relative to the real curve under identical conditions, yet remained within an acceptable range of error. Our study successfully validated the feasibility of utilizing hydrogen-oxygen combustion launch schemes for small load ejection, offering a valuable reference point for future research and optimization in this domain. © 2024 Institute of Physics Publishing. All rights reserved.

关键词： Explosives

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Lattice thermal conductivity switching via structural phase transition in ferromagnetic VI_(3)

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Chinese Physics B 2023年第5期32卷 20-26页

作者：吴超刘晨晗 Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China Micro-and Nano-scale Thermal Measurement and Thermal Management Laboratory School of Energy and Mechanical EngineeringNanjing Normal UniversityNanjing 210023China Jiangsu Key Laboratory for Numerical Simulation of Large-Scale Complex Systems Nanjing Normal UniversityNanjing 210023China Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments School of Mechanical EngineeringSoutheast UniversityNanjing 211100China

The realization of reversible thermal conductivity through ferromagnetic ordering can improve the heat management and energy efficiency in magnetic materials-based ***_(3),as a new layered ferromagnetic semiconductor,exhibits a structural phase transition from monoclinic(C2/m)to rhombohedral(R3^(-))phase as temperature decreases,making it a suitable platform to investigate thermal switching in magnetic phase transition *** work reveals that the thermal switching ratio of VI_(3)can reach 3.9 along the *** properties analysis indicates that the C2/m structure is stiffer than the R^(-)one,causing the larger phonon velocity in C2/m ***,due to the fewer phonon branches in C2/m phase,the number of phonon–phonon scattering channels in C2/m phase is smaller compared to that of R^(-)*** the larger phonon velocity and the longer phonon lifetime lead to larger lattice thermal conductivity in C2/m *** study uncovers the mechanical and thermal properties of VI_(3),which provides useful guides for designing magnetic materials-based devices such as thermal switch.

关键词： thermal switching ferromagnetic ordering phonons

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Effects of phonon bandgap on phonon-phonon scattering in ultrahigh thermal conductivityθ-phase TaN

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Chinese Physics B 2023年第4期32卷 543-548页

Phonon bandgap typically has a significant effect on phonon-phonon scattering *** this work,the effects of mass modified phonon bandgap inθ-phase Ta N are systemically investigated by the means of first-principles calculations with linearized Boltzmann transport *** detailed calculations,we find that phonon bandgap has a significant effect on three-phonon process while exhibits a much weaker effect on four-phonon *** reason for the ultrahigh thermal conductivity ofθ-phase Ta N is the long lifetime of phonons including both three-phonon and four-phonon processes,which originates from the weak phonon anharmonicity and large phonon bandgap-induced small phonon-phonon scattering phase *** work advances the understanding of phonon bandgap effects on phonon transport.

关键词： ultrahigh thermal conductivity phonon-phonon scattering phase space first-principles calculation phonon bandgap

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A simplified volume of fluid method for interface tracking on adaptive Cartesian grids 4

A simplified volume of fluid method for interface tracking o...

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4th Research, Invention, and Innovation Congress: Innovative Electricals and Electronics, RI2C 2023

作者： Suwito, Galing Tirtojati Vorspohl, Julian Juntasaro, Ekachai Mechanical Engineering Simulation and Design Group The Sirindhorn International Thai-German Graduate School of Engineering King Mongkut’s University of Technology North Bangkok Bangkok Thailand Institute of Aerodynamics RWTH Aachen University Aachen Germany

ISBN: (纸本)9798350330618

The interface tracking method is one of the most critical issues in computational fluid dynamics (CFD) fields. This research extends a simplified volume of fluid (SVOF) method for interface tracking on multiphase flow to adaptive Cartesian grids. The SVOF method for uniform meshes is modified to ensure the accurate calculation of fluxes between cells at different resolutions. The adaptive mesh refinement (AMR) enables the grid to be refined in specific areas during the simulation to reduce the necessary computational effort. Several benchmark cases are carried out for validation, including linear and vortex advection cases. This study discusses the outcomes between uniform meshes and adaptively refined meshes. Different types of interpolation weights of the SVOF and the bandwidth size of the AMR are also varied to find the effect on the accuracy of the simulation. This study shows that the AMR technique can provide robust, conservative, and accurate interface tracking and is a promising candidate for the use in multiphase flow simulations. ©2023 IEEE.

关键词： Computational fluid dynamics

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A Subdivision-Based Combined Shape and Topology Optimization in Acoustics

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Computer Modeling in engineering & Sciences 2024年第4期139卷 847-872页

作者： Chuang Lu Leilei Chen Jinling Luo Haibo Chen CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei230027China College of Intelligent Construction Wuchang University of TechnologyWuhan430223China Henan International Joint Laboratory of Structural Mechanics and Computational Simulation School of Architecture and EngineeringHuanghuai UniversityZhumadian463000China Beijing Aerospace Technology Institute Beijing100074China

We propose a combined shape and topology optimization approach in this research for 3D acoustics by using the isogeometric boundary element method with subdivision *** existing structural optimization methods mainly contain shape and topology schemes,with the former changing the surface geometric profile of the structure and the latter changing thematerial distribution topology or hole topology of the *** the present acoustic performance optimization,the coordinates of the control points in the subdivision surfaces fine mesh are selected as the shape design parameters of the structure,the artificial density of the sound absorbing material covered on the structure surface is set as the topology design parameter,and the combined topology and shape optimization approach is established through the sound field analysis of the subdivision surfaces boundary element method as a *** topology and shape sensitivities of the approach are calculated using the adjoint variable method,which ensures the efficiency of the *** geometric jaggedness and material distribution discontinuities that appear in the optimization process are overcome to a certain degree by the multiresolution method and solid isotropic material with *** examples are given to validate the effectiveness of the presented optimization approach.

关键词： Subdivision surfaces boundary element method topology optimization shape optimization combined optimization

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General theory for designing phonon transport in alloyed/doped materials

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Science China(Physics,Mechanics & Astronomy) 2024年第12期67卷 133-140页

作者： Chenhan Liu Chao Wu Wei Liu Yunshan Zhao Gang Zhang Hongmin Yang Yunfei Chen Micro-and Nano-scale Thermal Measurement and Thermal Management Laboratory Key Laboratory of Numerical Simulation for Large Complex SystemsMinistry of EducationSchool of Energy and Mechanical EngineeringNanjing Normal UniversityNanjing210023China School of Electrical and Automation Engineering Nanjing Normal UniversityNanjing210023China Phonon Engineering Research Center of Jiangsu Province Center for Quantum Transport and Thermal Energy ScienceInstitute of Physics Frontiers and Interdisciplinary SciencesSchool of Physics and TechnologyNanjing Normal UniversityNanjing210023China Agency for Science Technology and ResearchInstitute of High-Performance ComputingSingapore138632Singapore Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments School of Mechanical EngineeringSoutheast UniversityNanjing211100China

Alloying/doping is a widely used technique for improving the electrical,mechanical,and optical properties of ***,this technology induces significant distortions in the lattice structure,mass distribution,and potential field,greatly enhancing phonon ***,we introduce the concept of alloying/doping path and employ crystal symmetry,lattice deformation,and electron distribution to characterize *** on this new concept,the phonon thermal transport behavior in alloyed/doped materials can be well designed,and along different alloying/doping paths,the difference in thermal conductivity can be up to 45 *** one hand,strategic alloying/doping that combines high crystal symmetry,large lattice contraction,and the same electron distribution suppresses phonon-phonon scattering phase space,induces phonon stiffening,and bolsters electronic structure symmetry,*** synergistic effects significantly improve thermal *** the other hand,random alloying/doping has a low symmetry,leading to the typical“U”shape of alloying/doping level-dependent thermal *** theory is corroborated in three-dimensional(3D)Si,2D MoS_(2),and quasi-1D TiS_(3),affirming its efficacy and broad applicability in controlling phonon transport.

关键词： phonon transport alloyed/doped materials crystal symmetry lattice contraction electronic structure

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Structure design and Energy Absorption Mechanism of a New Type of Armor Inspired from Armadillos

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Acta Mechanica Solida Sinica 2021年第5期34卷 718-728页

作者： Chunan Du Gang Yang De’an Hu Xu Han Key Laboratory of Advanced Design and Simulation Techniques for Special Equipment Ministry of EducationHunan UniversityChangsha410082China School of Mechanical Engineering Hebei University of TechnologyTianjin300401China

Dermal armor,such as fish scales or armadillo osteoderms,has been known to exhibit high performance and good flexibility defending against *** top layer of the dermal armor usually consists of a segmented hard bony *** soft inner layer composed of collagen fibers connects and holds the hard *** by the dermal armor of armadillos,bioinspired protection armor is studied for impact *** hexagonal scales tessellate the surface continuously and work as the hard bony layer protecting the soft inner layer from ***-high molecular weight polyethylene(UHMWPE)is used as the connectivity layer to support and hold the *** investigate the dynamic response of the bioinspired protection armor,drop weight impact tests are carried out.A finite element model is established to study the dynamic response of bioinspired protection *** impact process images captured by a high speed camera and the experimental data of drop hammer acceleration tests verify the validity of the numerical *** dynamic resistance behavior and the synergy effect of each part of the bioinspired protection armor combined with the protected objects are studied in detail by numerical *** results show that the bioinspired protection armor has marked energy absorption ability.A synergistic dissipation mechanism is activated in the impact process,which can dissipate impact energy and make the impact load distribution more *** UHMWPE between the outer layer and the soft substrate plays a significant role not only related to support and connection,but also for the force balance and energy *** mechanism of energy absorption of the bioinspired protection armor revealed in this paper can be taken as a new guideline for designing a novel protective armor.

关键词： Bioinspired Armor Impact Energy absorption Numerical simulation

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