检索结果-南通市图书馆

Enhanced design of hourglass truss sandwich structures for compressive resistance

Science China(Technological Sciences) 2020年第12期63卷 2717-2728页

作者： FENG LiJia YU GuoCai MA Li WU LinZhi ZHANG AMan College of Shipbuilding Engineering Harbin Engineering UniversityHarbin 150001China Key Laboratory of advanced Ship materials and mechanics College of Aerospace and Civil EngineeringHarbin Engineering UniversityHarbin 150001China center for Composite materials Harbin Institute of TechnologyHarbin 150001China

In this article,the design of the hourglass truss sandwich structure is improved by optimizing the number of layers to enhance the compressive strength of both the core and the face sheet and then its mechanical performance. The hourglass truss structures characterized by three different numbers of layers are manufactured using an interlocking and vacuum brazing method. The effect of the layer number of the hourglass core panels on their out-of-plane compression and in-plane compression performance is investigated,and the results from calculations and experiments are in reasonable agreement. The results show that as the layer number of the hourglass core increases,the out-of-plane compressive strengths show little change,but their energy absorption properties are effectively increased. The in-plane compressive failure mechanism maps are constructed,and the specimens are designed to examine the local elastic and inelastic buckling failure modes of the face sheets. The results suggest that as the number of layers of the hourglass core increases,its maximum in-plane compressive load increases. The maximum in-plane compressive loads of the two-layer hourglass truss panels are 57%–70% higher than those of the single-layer panels. It can also be concluded that the out-of-plane and in-plane compression mechanical properties of the multilayer hourglass truss outperform those of the pyramidal truss. Furthermore,the number of layers of the hourglass core is optimized in consideration of both mechanical properties and fabrication cost.

关键词： multilayer hourglass truss truss sandwich structure out-of-plane compression in-plane compression

来源：

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

EQUIVALENT MODEL OF EXPANSION OF CEMENT MORTAR UNDER SULPHATE EROSION

引用

Acta Mechanica Solida Sinica 2008年第4期21卷 327-332页

作者： Jue Zhu Minqiang Jiang Jiankang Chen mechanics and materials Science Research center Ningbo University Ningbo 315211 China State Key Laboratory of Nonlinear mechanics （LNM） Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

The expansion property of cement mortar under the attack of sulfate ions is studied by experimental and theoretical methods. First, cement mortars are fabricated with the ratio of water to cement of 0.4, 0.6, and 0.8. Secondly, the expansion of specimen immerged in sulphate solution is measured at different times. Thirdly, a theoretical model of expansion of cement mortar under sulphate erosion is suggested by virtue of represent volume element method. In this model, the damage evolution due to the interaction between delayed ettringite and cement mortar is taken into account. Finally, the numerical calculation is results indicate that the model perfectly describes performed. The numerical and experimental the expansion of the cement mortar.

关键词： size effect microvoids expansion sodium sulfate attack

来源：

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

Dynamic Fracture Behaviors of Selected Aluminum Alloys Under Three-point Bending

引用

Defence Technology（防务技术） 2013年第4期9卷 193-200页

作者： Ming-zhi XING Yong-gang WANG Zhao-xiu JIANG mechanics and materials Science Research center Ningbo University

The dynamic fracture behaviors of the extruded 2024-T4 and 7075-T6 aluminum alloys are investigated by using an instrumented drop tower *** specimens are made from a 25 mm diameter extruded circular *** dynamic three-point bending tests of each alloy are carried out at different impact *** initiation fracture toughness and average propagation fracture toughness of 2024-T4 and 7075-T6 are determined at different loading *** results show that both the initiation toughness and the propagation toughness increase with the loading ***,the difference between the fracture toughness behaviors of 2024-T4 and 7075-T6 is found to be dependent on the variation of fracture *** comprehensive fractographic investigations of the fracture surfaces clearly demonstrate that the fracture mode of 2024-T4 is predominantly transgranular fracture with high density small-sized dimples,and the fracture mode of 7075-T6 is mainly intergranular fracture with many intermetallic particles in the bottom of voids located in the fracture surface.

关键词：动态断裂行为三点弯曲试验铝合金行为研究断裂韧性加载速率断裂模式 IRMA

来源：

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

Molecular transport under extreme confinement

引用

Science China(Physics,mechanics & Astronomy) 2022年第6期65卷 1-10页

作者： FengChao Wang JianHao Qian JingCun Fan JinChuan Li HengYu Xu HengAn Wu 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 230027China

Mass transport through the nanoporous medium is ubiquitous in nature and *** the macroscale transport phenomena which have been well understood by the theory of continuum mechanics,the relevant physics and mechanics on the nanoscale transport still remain *** developments in fabrication of slit-like nanocapillaries with precise dimensions and atomically smooth surfaces have promoted the fundamental research on the molecular transport under extreme *** this review,we summarized the contemporary progress in the study of confined molecular transport of water,ions and gases,based on both experiments and molecular dynamics *** liquid exhibits a pronounced layered structure that extends over several intermolecular distances from the solid surface,which has a substantial influence on static properties and transport behaviors under *** studies have also shown that those molecular details could provide some new understanding on the century-old classical theory in this field.

关键词： confined mass transport nanocapillary solid-liquid interface confinement effect

来源：

维普期刊数据库

同方期刊数据库

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

Emergent antisymmetric wrinkling patterns in films on ridged substrates

引用

Science China(Physics,mechanics & Astronomy) 2023年第11期66卷 179-187页

作者： Jiahui Zhang Yi Sun Linghui He Yong Ni 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 ChinaHefei230026China

We report the formation of antisymmetric wrinkling patterns in films on ridged substrates induced by the buckling instability of the substrates via finite element simulations and *** simulated results reveal that the uniaxial compression along the ridge can trigger both the wrinkling instability of the film and the lateral buckling instability of the *** latter could change the wrinkles from a symmetric pattern to an antisymmetric pattern in a range of film-substrate modulus ratio and aspect ratio of the ridge profile,as validated by the experimental observations.A three-dimensional phase diagram with four buckling patterns,i.e.,sole ridge buckling pattern,antisymmetric wrinkling pattern with different wavelengths from ridge buckling,symmetric wrinkling pattern without ridge buckling,and antisymmetric wrinkling pattern with the same wavelength as ridge buckling,is built with respect to the uniaxial compression,modulus ratio,and aspect *** results not only elucidate how and when the interplay between the wrinkling instability and the ridge instability results in the formation of the antisymmetric wrinkling pattern but also offer a way to generate controllable complex wrinkling patterns.

关键词： wrinkling pattern buckling instability ridged film-substrate system antisymmetric wrinkles

来源：

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

Hard-magnetic liquid metal droplets with excellent magnetic field dependent mobility and elasticity

引用

Journal of materials Science & Technology 2021年第33期92卷 60-68页

作者： Xiaokang He Mingyang Ni Jianpeng Wu Shouhu Xuan Xinglong Gong 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 230027China

Magnetic liquid metal droplets(MLMDs)have been proven to be very important in many fields such as flexible electronics and soft ***,soft magnetic particles such as nickel(Ni)and iron(Fe)are mixed or suspended into the liquid metal to obtain soft MLMDs(S-LMDs),which can be easily manipulated under the magnetic field due to the favorable deformability and *** addition,hard magnetic particles such as neodymium iron boron(Nd Fe B)with a high residual magnetization can also be dispersed into the liquid metal and the hard MLMDs(H-LMDs)become more compact due to the interaction between internal particles induced by *** work reports a kind of H-LMDs with high surface tension,high flexibility and mechanical robustness,whose electrical conductivity and strength are better than the *** the magnetic field,the H-LMDs have a faster response time(0.58 s)and a larger actuating velocity(4.45 cm/s)than the ***,the H-LMDs show excellent magnetic controllability,good elasticity and favorable mobility,as demonstrated by magnetically actuated locomotion,bounce tests and rolling angle ***,the droplets can be further applied in wheeldriven motors and micro-valve switches,which demonstrates their high application potential in robotic manipulation and microfluidic devices.

关键词： Magnetic liquid metal droplets NdFeB particles Magnetic controllability Micro-valve

来源：

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

Atomic-scale study on the precipitation behavior of an Al-Zn-Mg-Cu alloy during isochronal aging

引用

Journal of materials Science & Technology 2022年第13期108卷 281-292页

作者： Xingpu Zhang Xiaotong Deng Haofei Zhou Jiangwei Wang center of Electron Microscopy and State Key Laboratory of Silicon materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China center for X-mechanics Department of Engineering MechanicsZhejiang UniversityHangzhou 310027China Wenzhou Key Laboratory of Novel Optoelectronic and Nano materials Institute of WenzhouZhejiang UniversityWenzhou 325006China

The precipitation behavior of a 7075 Al alloy during isochronal heat treatments at three different heating rates has been studied using differential scanning calorimetry,high-angle-annular-dark-field scanningtransmission-electron microscope and density functional theory *** the early stage of aging,GPI and GPII zones form sequentially and cause two characteristic DSC ***,the formation ofη_(1) precipitates takes place concurrently withη’.A novel type of metastable phaseη_(1)’is identified as the precursor ofη_(1),which can lower the lattice misfit betweenη_(1) and Al matrix along the direction of[1010]_(η_(1))//[001]_(Al).Accordingly,a pathway for the formation ofη_(1) viaη_(1)’is ***η’together withη_(1) andη_(1)’contribute to the third DSC *** the further increase of temperature,ηprecipitates become *** on the quantitative analyses,the influence of the heating rate and ending temperature on the cross section and number density of phases formed is discussed.

关键词： Al-Zn-Mg-Cu alloys Precipitation Isochronal ageing HAADF-STEM Density functional theory

来源：

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

Coordinated grain boundary deformation governed nanograin annihilation in shear cycling

引用

Journal of materials Science & Technology 2021年第27期86卷 180-191页

作者： Yingbin Chen Qishan Huang Qi Zhu Kexing Song Yanjun Zhou Haofei Zhou Jiangwei Wang center of Electron Microscopy and State Key Laboratory of Silicon materials School of Materials Science and EngineeringZhejiang UniversityHangzhou310027PR China center for X-mechanics Department of Engineering MechanicsZhejiang UniversityHangzhou310027PR China School of materials Science&Engineering Henan University of Science and TechnologyLuoyang471023PR China

Grain growth and shrinkage are essential to the thermal and mechanical stability of nanocrystalline metals,which are assumed to be governed by the coordinated deformation between neighboring grain boundaries(GBs)in the nanosized ***,the dynamics of such coordination has rarely been reported,especially in *** this work,we systematically investigate the atomistic mechanism of coordinated GB deformation during grain shrinkage in an Au nanocrystal film through combined stateof-the-art in situ shear testing and atomistic *** demonstrate that an embedded nanograin experiences shrinkage and eventually annihilation during a typical shear loading *** continuous grain shrinkage is accommodated by the coordinated evolution of the surrounding GB network via dislocation-mediated migration,while the final grain annihilation proceeds through the sequential dislocation-annihilation-induced grain rotation and merging of opposite *** experiments and simulations show that stress distribution and GB structure play important roles in the coordinated deformation of different GBs and control the grain shrinkage/annihilation under shear *** findings establish a mechanistic relation between coordinated GB deformation and grain shrinkage,which reveals a general deformation phenomenon in nanocrystalline metals and enriches our understanding on the atomistic origin of structural stability in nanocrystalline metals under mechanical loading.

关键词： Nanocrystalline metals Grain shrinkage and annihilation Grain boundary migration Grain rotation Coordinated deformation

来源：

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

Kinetics of Glass Transition and Crystallization in Carbon Nanotube Reinforced Mg-Cu-Gd Bulk Metallic Glass

引用

Journal of Rare Earths 2006年第3期24卷 327-331页

作者：王银春王育人魏炳忱李维火孙玉峰 Institute of mechanics Chinese Academy of Sciences Beijing 100080 China Research center for materials Department of Materials Science and Engineering Zhengzhou University Zhengzhou 450002 China

Mg65Cu25Gd10 bulk metallic glass and its carbon nanotube reinforced composite were prepared. Differential scanning calorimeter （DSC） was used to investigate the kinetics of glass transition and crystallization processes. The influence of CNTs addition to the glass matrix on the glass transition and crystallization kinetics was studied. It is shown that the kinetic effect on glass transition and crystallization are preserved for both the monothetic glass and its glass composite. Adding CNTs in to the glass matrix reduces the influence of the heating rate on the crystallization process. In addition, the CNTs increase the energetic barrier for the glass transition. This results in the decrease of GFA. The mechanism of the GFA decrease was also discussed.

关键词： metallic glass carbon nanotube glass transition crystallization kinetic effect composite glass Gadolinium rare earths

来源：

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

Effect of niobium substitution on microstructures and thermal stability of TbCu7-type Sm-Fe-N magnets

引用

Journal of Rare Earths 2018年第3期36卷 281-286页

作者： Guiyong Wu Hongwei Li Dunbo Yu Kuoshe Li Wenlong Yan Chao Yuan Liang Sun Yang Luo Kun Zhang National Engineering Research center for Rare Earth materials General Research Institute for Nonferrous MetalsGrirem Advanced Materials Co.Ltd.Beijing 100088China Key Laboratory of Microgravity(National Microgravity Laboratory) Institute of MechanicsChinese Academy of SciencesBeijing 100190China

This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of X-ray diffraction, vibrating sample magnetometer, flux meter and transmission electron microscope. It is found that the lattice parameter ratio c/a of TbCu7-type crystal structure increases with Nb substitution, which indicates that the Nb can increase the stability of the metastable phase in the Sm-Fe ribbons. Nb substitution impedes the formation of magnetic soft phase a-Fe in which reversed domains initially form during the magnetization reversal process. Meanwhile, Nb substitution refines grains and leads to homogeneous micro structure with augmented grain boundaries. Thus the exchange coupling pining field is enhanced and irreversible domain wall propagation gets suppressed. As a result, the magnetic properties are improved and the irreversible flux loss of magnets is notably decreased. A maximum value 771.7 kA/m of the intrinsic coercivity H（cj） is achieved in the 1.2 at% substituted *** irreversible flux loss for 2 h exposure at 120 ℃ declines from 8.26% for Nb-free magnets to 6.32% for magnets with 1.2 at% Nb substitution.

关键词： Magnetic properties Thermal stability Grain size Pinning field Irreversible flux loss Rare earths

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：