检索结果-南通市图书馆

Maintaining the Spatial Periodicity in the Topology Optimization of Phononic Crystals for Bandgap Maximization and Creation

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Maintaining the Spatial Periodicity in the Topology Optimiza...

design rules for a tunable merged-tip microneedle

The Seventh China-Japan-Korea Joint Symposium on Optimization of Structural and mechanical Systems

作者： Young Kwan Ahn Joo Hwan Oh Pyung Sik Ma Yoon Jae Kim Yoon Young Kim wcu multiscale mechanical design division School of Mechanical and Aerospace EngineeringSeoul National University599 Gwanak-GuSeoul 151-742Korea Institute of Advanced Machinery and design School of Mechanical and Aerospace EngineeringSeoul National University599 Gwanak-GuSeoul 151-742Korea

Crystal structures having periodically arranged inclusions inside a homogeneous matrix,called Phononic Crystals （PC’s）,exhibit various wave phenomena such as negative refraction,wave focusing,mode splitting,***,one of the most remarkable properties is a bandgap phenomenon,which refers to wave propagations inside a PC are forbidden in certain *** the bandgap phenomenon is applied in various applications such as wave guiding and wave filtering etc.,there have been growing needs for the PC having wider bandgap frequency ranges.A number of researches [1-4] have successfully designed PC’s having the maximized bandgap frequency *** researches have shown that the design of the unit cell of PC’s can be ***,no earlier investigation has so far paid attentions to the singular issue which will be mainly concerned in this paper - the reduction of the spatial *** found that the optimized unit cell may correspond to shorter spatial periods so that the initial assumption on the periodicity is no longer *** means that the size of the unit cell in the direct lattice originally defined in the topology optimization formulation often turns out to be reduced in the final optimized unit cell especially when the creation and maximization of a bandgap are simultaneously *** unit cell size reduction can occur in various lattice structures including square and rectangular unit *** is found that the reduction of the spatial period can be a critical problem because the reduction can lead to incorrect optimized ***,without any control on the periodicity,maintaining the originally set-up periodicity is not ***,a new technique is required to avoid the reduction of the spatial *** dealing with a technique to control the cell size during optimization iterations,the first part of this work is focused on the explanation of the issue in some details about the characteristic of reduced unit cell

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2018年第1期4卷 85-94页

作者： Jungeun Lim Dongha Tahk James Yu Dal-Hee Min Noo Li Jeon School of mechanical and Aerospace Engineering Seoul National UniversitySeoul 08826South Korea division of wcu multiscale mechanical design Seoul National UniversitySeoul 08826South Korea Institute of Advanced Machinery and design Seoul National UniversitySeoul 08826South Korea Interdisciplinary Program for Bioengineering Seoul National UniversitySeoul 08826South Korea Department of Chemistry Seoul National UniversitySeoulSouth Korea

This publication proposes the use of an elasto-capillarity-driven self-assembly for fabricating a microscale merged-tip structure out of a variety of biocompatible UV-curable polymers for use as a microneedle *** addition,the novel merged-tip microstructure constitutes a new class of microneedles,which incorporates the convergence of biocompatible polymer micropillars,leading to the formation of a sharp tip and an open cavity capable of both liquid trapping and volume *** combined with biocompatible photopolymer micropillar arrays fabricated with photolithography,elasto-capillarity-driven self-assembly provides a means for producing a complex microneedle-like structure without the use of micromolding or *** publication also explores and defines the design rules by which several fabrication aspects,such as micropillar dimensions,shapes,pattern array configurations,and materials,can be manipulated to produce a customizable microneedle array with controllable cavity volumes,fracture points,and merge *** addition,the incorporation of a modular through-hole micropore membrane base was also investigated as a method for constitutive payload delivery and fluid-sampling *** flexibility and fabrication simplicity of the merged-tip microneedle platform holds promise in transdermal drug delivery applications.

关键词： microstructure needle cavity

mechanically robust bamboo node and its hierarchically fibrous structural design

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2023年第2期10卷 199-211页

作者： Si-Ming Chen Si-Chao Zhang Huai-Ling Gao Quan Wang LiChuan Zhou Hao-Yu Zhao Xin-Yu Li Ming Gong Xiao-Feng Pan Chen Cui Ze-Yu Wang YongLiang Zhang HengAn Wu Shu-Hong Yu Department of Chemistry Institute of Biomimetic Materials & Chemistry Anhui Engineering Laboratory of Biomimetic MaterialsDivision of Nanomaterials & Chemistry Hefei National Research Center for Physical Sciences at the Microscale Institute of Energy Hefei Comprehensive National Science Center University of Science and Technology of China CAS Key Laboratory of mechanical Behavior and design of Materials Department of Modern MechanicsEngineering and Materials Science Experiment CenterUniversity of Science and Technology of China Institute of Innovative Materials (I2M) Department of Materials Science and EngineeringDepartment of Chemistry Southern University of Science and Technology

Although short bamboo nodes function in mechanical support and fluid exchange for bamboo survival,their structures are not fully understood compared to unidirectional fibrous ***,we identify the spatial heterostructure of the bamboo node via multiscale imaging strategies and investigate its me chanical properties by multimodal mechanical *** find three kinds of hierarchical fiber reinforcement schemes that originate from the bamboo node,including spatially tightened interlocking,triaxial interconnected scaffolding and isotropic *** reinforcement schemes,built on porous vascular bundles,microfibers and more-refined twist-aligned nanofibers,govern the structural stability of the bamboo via hierarchical *** addition,the spatial liquid transport associated with these multiscale fibers within the bamboo node is experimentally verified,which gives perceptible evidence for life-indispensable multidirectional fluid *** functional integration of mechanical reinforcement and liquid transport reflects the fact that the bamboo node has opted for elaborate structural optimization rather than ingredient *** study will advance our understanding of biological materials and provide insight into the design of fiber-reinforced structures and biomass utilization.

关键词： biological materials bamboo node hierarchical fiber structural reinforcement functional integration

Biomimetic twisted plywood structural materials

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2018年第5期5卷 703-714页

作者： Si-Ming Chen Huai-Ling Gao Yin-Bo Zhu Hong-Bin Yao Li-Bo Mao Qi-Yun Song Jun Xia Zhao Pan Zhen He Heng-An Wu Shu-Hong Yu division of Nanomaterials & Chemistry Hefei National Research Center for Physical Sciences at the MicroscaleCAS Center for Excellence in NanoscienceHefei Science Center of CASCollaborative Innovation Center of Suzhou Nano Science and TechnologyDepartment of ChemistryUniversity of Science and Technology of China CAS Key Laboratory of mechanical Behavior and design of Materials Department of Modern MechanicsCAS Center for Excellence in Complex System MechanicsUniversity of Science and Technology of ChinaHefei 230027China3 Anhui Key Laboratory of Condensed Matter Physics at Extreme ConditionsHigh Magnetic Field LaboratoryChinese Academy of Sciences CAS Key Laboratory of mechanical Behavior and design of Materials Department of Modern MechanicsCAS Center for Excellence in Complex System MechanicsUniversity of Science and Technology of China Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field LaboratoryChinese Academy of Sciences

Biomimetic designs based on micro/nanoscale manipulation and scalable fabrication are expected to develop new-style strong, tough structural materials. Although the mimicking of nacre-like‘brick-and-mortar’ structure is well studied, many highly ordered natural architectures comprising 1D micro/nanoscale building blocks still elude imitation owing to the scarcity of efficient manipulation techniques for micro/nanostructural control in practical bulk counterparts. Herein, inspired by natural twisted plywood structures with fascinating damage tolerance, biomimetic bulk materials that closely resemble natural hierarchical structures and toughening mechanisms are successfully fabricated through a programmed and scalable bottom-up assembly strategy. By accurately engineering the arrangement of 1D mineral micro/nanofibers in biopolymer matrix on the multiscale, the resultant composites display optimal mechanical performance, superior to many natural, biomimetic and engineering materials. The design strategy allows for precise micro/nanostructural control at the macroscopic 3D level and can be easily extended to other materials systems, opening up an avenue for many more micro/nanofiber-based biomimetic designs.

关键词： biomimetic designs micro/nanoscale building blocks twisted plywood structures damage tolerance biomimetic bulk materials toughening mechanisms

Tailoring magnetic hysteresis of additive manufactured Fe-Ni permalloy via multiphysics-multiscale simulations of process-property relationships

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2023年第1期9卷 1297-1315页

作者： Yangyiwei Yang Timileyin David Oyedeji Xiandong Zhou Karsten Albe Bai-Xiang Xu Mechanics of Functional Materials division Institute of Materials ScienceTechnische Universität DarmstadtDarmstadt 64287Germany Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province College of Architecture and EnvironmentSichuan UniversityChengdu 610207China Materials Modelling division Institute of Materials ScienceTechnische Universität DarmstadtDarmstadt 64287Germany

designing the microstructure of Fe-Ni permalloy produced by additive manufacturing(AM)opens new avenues to tailor its magnetic ***,AM-produced parts suffer from spatially inhomogeneous thermal-mechanical and magnetic responses,which are less investigated in terms of process modeling and *** present a powder-resolved multiphysics-multiscale simulation scheme for describing magnetic hysteresis in AM-produced material,explicitly considering the coupled thermal-structural evolution with associated thermo-elasto-plastic behaviors and chemical order-disorder *** residual stress is identified as the key thread in connecting the physical processes and phenomena across *** employing this scheme,we investigate the dependence of the fusion zone size,the residual stress and plastic strain,and the magnetic hysteresis of AM-produced Fe_(21.5)Ni_(78.5) on beam power and scan *** results also suggest a phenomenological relation between magnetic coercivity and average residual stress,which can guide the magnetic hysteresis design of soft magnetic materials by choosing appropriate processing parameters.

关键词： alloy microstructure hysteresis

Functional Tough Hydrogels: design, Processing, and Biomedical Applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Accounts of Materials Research 2023年第2期4卷 101-114页

作者： Xiao Kuang Mehmet Onur Arıcan Tao Zhou Xuanhe Zhao Yu Shrike Zhang division of Engineering in Medicine Department of MedicineBrigham and Women’s HospitalHarvard Medical SchoolCambridgeMassachusetts 02139United States Department of Polymer Science and Technology Kocaeli University41001 KocaeliTurkey

Hydrogels are high-water-content soft materials with widely tunable physicochemical properties,resembling soft *** progress in engineering hydrogels with good biocompatibility,suitable bioactivities,and controlled geometries has made them promising candidates for broad ***,conventional hydrogels usually suffer from weak mechanical properties,limiting their use in biomedical settings involving load-bearing and persistent mechanical *** by the extreme mechanical properties and multiscale hierarchical structures of biological tissues,mechanically robust tough hydrogels have been *** robust mechanical properties and other desired performance characteristics in functional tough hydrogels expands their opportunities in biomedical *** Account seeks to guide the readership regarding the recent progress in functional tough hydrogels with a focus on molecular/structural design and novel fabrications,particularly surrounding the works reported by our ***,functional tough hydrogels for multiple biomedical applications are discussed,highlighting the underlying mechanisms governing their relevant *** begin by introducing the definition,measurements,and design principles of tough hydrogels and hydrogel adhesives in terms of soft materials *** molecular and structural engineering approaches by building mechanical dissipation into stretchable hydrogels to realize stress homogenization or energy dissipation are exploited to fabricate tough *** engineering-based network architecture design of homogeneous hydrogels and structural engineering-based design of heterogeneous hydrogels are *** conventional energy-dissipation-based tough hydrogels are reinforced by the sacrificial bonds or components,leading to a substantial toughness reduction in subsequent loading *** this end,new molecular designs,including highly entangled hydrogels and sl

关键词： Hydrogel bonds dealing

Spatial correlation of elastic heterogeneity tunes the deformation behavior of metallic glasses

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2018年第1期4卷 493-502页

作者： Neng Wang Jun Ding Feng Yan Mark Asta Robert O.Ritchie Lin Li Department of Metallurgical and Materials Engineering The University of AlabamaTuscaloosaAL 35487USA Materials Sciences division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Center for Materials for Information Technology The University of AlabamaTuscaloosaAL 35487USA Department of Materials Science and Engineering University of CaliforniaBerkeleyCA 94720USA

Metallic glasses(MGs)possess remarkably high strength but often display only minimal tensile ductility due to the formation of catastrophic shear *** enhancing the inherent heterogeneity to promote distributed flow offers new possibilities in improving the ductility of monolithic ***,we report the effect of the spatial heterogeneity of elasticity,resulting from the inherently inhomogeneous amorphous structures,on the deformation behavior of MGs,specifically focusing on the ductility using multiscale modeling methods.A highly heterogeneous,Gaussian-type shear modulus distribution at the nanoscale is revealed by atomistic simulations in Cu_(64)Zr_(36) MGs,in which the soft population of the distribution exhibits a marked propensity to undergo the inelastic shear *** employing a mesoscale shear transformation zone dynamics model,we find that the organization of such nanometer-scale shear transformation events into shear-band patterns is dependent on the spatial heterogeneity of the local shear moduli.A critical spatial correlation length of elastic heterogeneity is identified for the simulated MGs to achieve the best tensile ductility,which is associated with a transition of shear-band formation mechanisms,from stress-dictated nucleation and growth to structure-dictated strain percolation,as well as a saturation of elastically soft sites participating in the plastic *** discovery is important for the fundamental understanding of the role of spatial heterogeneity in influencing the deformation behavior of *** believe that this can facilitate the design and development of new ductile monolithic MGs by a process of tuning the inherent heterogeneity to achieve enhanced ductility in these high-strength metallic alloys.

关键词： deformation ductility glasses