检索结果-南通市图书馆

Consistent constitutive modeling of metallic target penetration using empirical, analytical, and numerical penetration models

引用

Defence Technology（防务技术） 2016年第2期12卷 201-213页

作者： John(Jack) P.RIEGEL III David DAVISON R3 Technology Inc. 7324 Fountain Spring Ct. shock transients Inc.

Historically, there has been little correlation between the material properties used in(1) empirical formulae,(2) analytical formulations, and(3) numerical models. The various regressions and models may each provide excellent agreement for the depth of penetration into semi-infinite targets. But the input parameters for the empirically based procedures may have little in common with either the analytical model or the numerical model. This paper builds on previous work by Riegel and Anderson(2014) to show how the Effective Flow Stress(EFS) strength model, based on empirical data, can be used as the average flow stress in the analytical Walker–Anderson Penetration model(WAPEN)(Anderson and Walker,1991) and how the same value may be utilized as an effective von Mises yield strength in numerical hydrocode simulations to predict the depth of penetration for eroding projectiles at impact velocities in the mechanical response regime of the materials. The method has the benefit of allowing the three techniques(empirical, analytical, and numerical) to work in tandem. The empirical method can be used for many shot line calculations, but more advanced analytical or numerical models can be employed when necessary to address specific geometries such as edge effects or layering that are not treated by the simpler methods. Developing complete constitutive relationships for a material can be costly. If the only concern is depth of penetration, such a level of detail may not be required. The effective flow stress can be determined from a small set of depth of penetration experiments in many cases, especially for long penetrators such as the L/D = 10 ones considered here, making it a very practical approach. In the process of performing this effort, the authors considered numerical simulations by other researchers based on the same set of experimental data that the authors used for their empirical and analytical assessment. The goals were to establish a baseline with a full constitut

关键词：本构模型渗透模型数值模型金属靶材料性质流动应力程序模拟数值计算

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

Programmable microfluidics for dynamic multiband camouflage

引用

Microsystems & Nanoengineering 2023年第2期9卷 275-282页

作者： Chunzao Feng Mingran Mao Xiaohui Zhang Yutian Liao Xiaohui Xiao Huidong Liu Kang Liu MOE Key Laboratory of Hydraulic Machinery transients School of Power and Mechanical EngineeringWuhan UniversityWuhan 430072 HubeiChina

Achieving multiband camouflage covering both visible and infrared regions is challenging due to the broad bandwidth and differentiated regulation demand in diverse *** this work,we propose a programmable microfluidic strategy that uses dye molecules in layered fluids to manipulate visible light-and infrared-semitransparent solvent to manipulate infrared *** three primary fluid inputs,we achieve 64 chromaticity values and 8 emissivities from 0.42 to *** view of the wide tuning range,we demonstrate that the microfluidic flm can dynamically change its surface reflectance to blend into varying backgrounds in both visible and infrared ***,we fabricate the microfluidic device in a textile form and demonstrate its ability to match exactly with the colors of natural leaves of different seasons in the full hyperspectrum *** the broadband modulation and ease of operation,the programmable microfluidic strategy provides a feasible approach for smart optical surfaces in long-span optical spectra.

关键词： multiband tuning visible

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Mechanical properties of nanocrystalline nanoporous gold complicated by variation of grain and ligament: A molecular dynamics simulation

引用

Science China(Technological Sciences) 2018年第9期61卷 1353-1363页

作者： LI JieJie XIAN YueHui ZHOU HongJian WU RunNi HU GuoMing XIA Re Key Laboratory of Hydraulic Machinery transients Ministry of Education Wuhan University Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan University

A series of large-scale molecular dynamics(MD) simulations has been performed to study the effects of grain size and ligament diameter on the mechanical properties of nanocrystalline nanoporous gold. Such simulations indicate that the principal deformation mechanism is a combination of grain boundary sliding, grain rotation and dislocation movement. The results of uniaxial tensile tests reveal the presence of a reverse Hall-Petch relation between strength and nominal grain size, rather than the conventional Hall-Petch relationship in the present range of nominal grain size(7.9–52.7 nm). An increase of flow stress may possibly attribute to the lower total proportion of grain boundary sliding and grain rotation in the deformation of samples with larger grain size. The Young's modulus shows a linear relation with the reciprocal of nominal grain size, which depends largely on the volume fraction of grain boundaries and thus decreasing grain size leads to relatively lower Young's modulus. MD simulations on samples with ligament diameter ranging from 4.07 to 8.10 nm are also carried out and results show that the increasing ligament diameter resulted in decreased flow stress and increased Young's modulus.

关键词： nanocrystalline nanoporous gold grain-size effect ligament-size effect mechanical properties molecular dynamics

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

A highly active and stable Sr_(2)Fe_(1.5)Mo(0.5)O_(6)‑δ‑Ce_(0.8)Sm_(0.2)O_(1.95)ceramic fuel electrode for efficient hydrogen production via a steam electrolyzer without safe gas

引用

International Journal of Coal Science & Technology 2022年第1期9卷 217-224页

作者： Yao Wang Tong Liu Key Laboratory of Hydraulic Machinery transients Ministry of EducationSchool of Power and Mechanical EngineeringWuhan UniversityHubei 430072 WuhanChina

High temperature steam(H_(2)O)electrolysis via a solid oxide electrolysis cell is an efficient way to produce hydrogen(H_(2))because of its high energy conversion efficiency as well as simple and green process,especially when the electrolysis process is combined with integrated gasification fuel cell technology or derived by renewable ***,about 60%-70%of the electricity input is consumed to overcome the large oxygen potential gradient but not for electrolysis to split H_(2)O to produce H_(2)due to the addition of safe gas such as H_(2)in the fuel *** this work,Sr_(2)Fe_(1.5)Mo_(0.5)O_(6)-δ-Ce_(0.8)Sm_(0.2)O_(1.95)(SFM-SDC)ceramic composite material has been developed as fuel electrode to avoid the use of safe gas,and the open circuit voltage(OCV)has been effectively lowered from 1030 to 78 mV when the feeding gas in the fuel electrode is shifted from 3%H_(2)O-97%H_(2)to 3%H_(2)O-97%N_(2),reasonably resulting in a significantly increased electrolysis *** addition,it is also demonstrated that the electrolysis current density is greatly enhanced by increasing the humidity in the fuel electrode and the working temperature.A considerable electrolysis current density of−0.54 A/cm^(2)is obtained at 800°C and 0.4 V for the symmetrical electrolyzer by exposing SFM-SDC fuel electrode to 23%H_(2)O-77%N_(2),and durability test at 800°C for 35 h demonstrates a relatively stable electrochemical performance for steam electrolysis under the same operation condition without safe gas and a constant electrolysis current density of−0.060 A/*** findings achieved in this work indicate that SFM-SDC is a highly promising fuel electrode for steam electrolysis.

关键词： Solid oxide electrolysis cell Steam electrolysis Fuel electrode Molybdenum doped strontium ferrite Safe gas

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Thermal Performance of Elliptical Fin-and-Tube Heat Exchangers with Vortex Generator under Various Inclination Angles

引用

Journal of Thermal Science 2021年第1期30卷 257-270页

作者： WANG Yucheng ZHAO Wensheng WANG Pengfei JIANG Jin LUO Xiangyu Key Laboratory of Hydraulic Machinery transients Ministry of EducationWuhan UniversityWuhan 430072China School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China

Elliptical fin-and-tube heat exchangers are commonly used in air conditioning,heating,refrigeration industries,and *** study numerically investigates the effect of vortex generators on the performance of elliptical fin-and-tube heat exchanger under different inclination *** this study,air flow that is in the transitional regime is selected as the working *** numbers at the inlet are varied in a range of 1300 to 2100,and the shear stress transport k-ωturbulence model is selected to solve the non-closure of basic turbulence *** ellipticity ratios of the tubes which are used for the analysis are between 0.6 and 1.0,and the inclination angles are varied from 15°to 75°.The effects of different inclination angles of vortex generators on the Colburn factor j,friction factor f,and efficiency index j/f are *** friction and Colburn factors are observed to increase with increasing vortex generator inclination *** is found that the efficiency factors for a 15°vortex generator inclination angle at 0.6,0.7,0.8,and 0.9 ellipticity ratios improve compared to the corresponding cases with no vortex ***,the vortex generator cannot improve the efficiency factor of the circular tube heat *** 3 D CFD method employed by this study has great potential for use in optimally designing the arrangement of the vortex generators to enhance the performance of heat exchangers.

关键词： heat exchanger vortex generator Colburn factor friction factor heat exchanger efficiency

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

Investigation of the hydrodynamics of slug flow in airlift pumps

引用

Chinese Journal of Chemical Engineering 2018年第12期26卷 2391-2402页

作者： Zhineng Wang Yong Kang Xiaochuan Wang Shijing Wu Xiaoyong Li Key Laboratory of Hydraulic Machinery transients Ministry of Education Wuhan University Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan University School of Power and Mechanical Engineering Wuhan University

A slug flow model considering the dispersed bubbles entrained from the tail of Taylor bubble(TB) and recoalesced with the successive TB was proposed. Experiment was conducted to test the validity of this model by using a high-speed camcorder and particle image velocimetry(PIV). It was found that the model was valid for predicting the characteristics of slug flow in airlift pump within average error of 14%. Moreover, large pipe diameter was found to accelerate the rise velocity of TB and decreases void fraction in liquid slug by a small margin.

关键词： Airlift pump Flow regimes Bubble Mass transfer Hydrodynamics

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 radial heat conduction on effective thermal conductivity of carbon nanotube bundles

引用

Science China(Technological Sciences) 2018年第12期61卷 1959-1966页

作者： WANG JianLi SONG YaMei ZHANG YuFeng HU YuHan YIN Hang GU YunFeng XIA Re CHEN YunFei Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments Southeast University College of Electronic and Mechanical Engineering Nanjing Forestry University Key Laboratory of Hydraulic Machinery transients (Wuhan University) Ministry of Education

The effect of the radial heat conduction on the effective thermal conductivity of carbon nanotube(CNT) bundles is studied by the nonequilibrium molecular dynamics(NEMD) method. The hexagonal CNT bundle consists of seven(10, 10) single-walled carbon nanotubes(SWCNTs). The radial heat conduction is induced by creating the vacancy defects in some segments of the constituent CNTs. Combined with the temperature differences and the inter-tube thermal resistances at the different segments,the radial heat flow in the CNT bundle is calculated. The maximum percentage of the radial heat flow is less than 7% with the presence of four defective CNTs, while the resultant decrement of the effective thermal conductivity of the bundle is about 18%.The present results indicate that the radial heat flow can significantly diminish the axial heat conduction in the CNT bundles,which probably explains the smaller effective thermal conductivity in the CNT assemblies compared to that of the individual CNTs.

关键词： axial thermal conductivity carbon nanotube bundle inter-tube thermal resistance radial heat flow

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

Solid-state alloying of Al-Mg alloys by accumulative roll-bonding:Microstructure and properties

引用

Journal of Materials Science & Technology 2022年第30期125卷 238-251页

作者： X.M.Mei Q.S.Mei J.Y.Li C.L.Li L.Wan F.Chen Z.H.Chen T.Xu Y.C.Wang Y.Y.Tan School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China Key Laboratory of Hydraulic Machinery transients(Wuhan University) Ministry of EducationWuhan 430072China School of Mechanical Engineering Wuhan Polytechnic UniversityWuhan 430023China

In this study,a novel solid-state alloying approach was adopted to fabricate Al-Mg alloys with high Mg contents(C_(Mg)) by accumulative roll-bonding(ARB)of Al and Mg elemental materials to ultrahigh *** results showed that the degree of alloying increased with the increase of ARB cycles and a supersaturatedα-Al solid solution accompanied with nanoprecipitates was formed in the Al-Mg alloys by ARB to 70 *** as-prepared Al-Mg alloys exhibited enhanced mechanical properties,with a maximum tensile strength of∼615 MPa and a tensile elongation of∼10%at C_(Mg)=13 wt.%.The high strength can be attributed to different mechanisms,namely solid solution strengthening,grain boundary strengthening,dislocation strengthening,and precipitation *** Al-Mg alloys showed increased work hardening with increasing C_(Mg),due to the enhanced formation of ***,no obvious drop in the intergranular corrosion(IGC)resistance was found in the Al-Mg alloys with C_(Mg) up to 13 wt.%.Moreover,sensitization treatment was found to induce little decrease in the IGC resistance of the Al-Mg alloys with C_(Mg)≤13 wt.%.We found that the excellent IGC resistance was due to the suppression of grain boundary precipitation by the preferred formation of precipitates within the grains that were induced by *** study indicated the novelty of the present solid-state alloying approach to achieving a superior combination of high mechanical properties and IGC resistance in Al-Mg alloys.

关键词： Solid-state alloying Al-Mg alloys Mechanical properties IGC resistance ARB

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

Size-dependent vibration and buckling of porous functionally graded microplates based on modified couple stress theory in thermal environments by considering a dual power-law distribution of scale effects

引用

Applied Mathematics and Mechanics(English Edition) 2024年第12期45卷 2075-2092页

作者： Feixiang TANG Shaonan SHI Siyu HE Fang DONG Sheng LIU Key Laboratory of transients in Hydraulic Machinery Ministry of Education School of Power and Mechanical Engineering Wuhan University China-EU Institute for Clean and Renewable Energy Huazhong University of Science &Technology The Institute of Technological Sciences Wuhan University

In this study, the thermodynamic behaviors of the intrinsic frequency and buckling temperature of rectangular plates of functionally graded materials(FGMs) are explored based on the modified couple stress theory(MCST) and the novel dual powerlaw scale distribution theory. The effects of linear, homogeneous, and non-homogeneous temperature fields on the frequency and buckling temperature of FGM microplates are evaluated in detail. The results show that the porosity greatly affects the mechanical properties of FGM plates, reducing their frequency and flexural temperature compared with non-porous plates. Different temperature profiles alter plate frequencies and buckling temperatures. The presence and pattern of scale effect parameters are also shown to be crucial for the mechanical response of FGM plates. The present research aims to provide precise guidelines for the micro-electro-mechanical system(MEMS) fabrication by elucidating the complex interplay between thermal, material, and structural factors that affect the performance of FGM plates in advanced applications.

关键词： 74H45 dual power law functionally graded material (FGM) O341 pore distribution scale distribution scale effect thermal buckling thermal vibration

来源：

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

Fracture toughness and destructive mechanism of ductile nanoporous metallic glass and its crystal-impregnated nanocomposite

引用

Science China(Technological Sciences) 2023年第11期66卷 3328-3342页

作者： ZHANG YuHang XU JianFei HU YiQun SU Lei DING SuHang WU WenWang XIA Re Key Laboratory of Hydraulic Machinery transients(Wuhan University) Ministry of EducationWuhan 430072China Department of Engineering Mechanics School of Naval ArchitectureOcean&Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Nanoporous metallic glasses(NPMGs)and crystalline/amorphous nanocomposites exhibit superior ductility over bulk macroscopic metallic glasses(MGs).Their fracture behaviors remain a mystery due to experimental technical *** this work,the fracture behaviors of pre-cracked NPMGs and crystal-impregnated nanoporous metallic glasses(CINPMGs)are investigated through large-scale molecular dynamics simulations,and the MG and crystal phases are amorphous Cu_(50)Zr_(50)and crystalline B2CuZr,*** toughness is determined by simultaneously considering the surface energy and plastic dissipated *** results confirm the excellent plasticity of both the pre-cracked NPMGs and *** progressive necking and ductile rupture of ligaments are responsible for generating NPMGs with prominent ductility and fracture ***,secondary cracking is also triggered,which can consume energy without extending the major crack,thus further improving fracture *** is also found that the fracture toughness of NPMGs can be improved by increasing the solid fraction of MG,and linear relation between fracture toughness and solid fraction can be *** impregnation effectively inhibits global failure as the crystal phase shields the individual amorphous *** plastic flow characterized by shear bands is observed in CINPMGs,and this homogeneous global deformation is facilitated by the crystalline/amorphous ***,the fracture toughness of CINPMGs is higher than that of the constituent single phases,regardless of the volume fraction of each *** material charts manifest that these two types of materials demonstrate promising potential in the material selection library for advanced structural design.

关键词： nanoporous metals crack fracture toughness nanocomposites metallic glasses

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：