检索结果-南通市图书馆

Improved mechanical properties and strengthening mechanism with the altered precipitate orientation in magnesium alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2022年第5期10卷 1256-1267页

作者： y.J.Wan y.Zeng y.C.Dou D.C.Hu x.y.Qian Q.Zeng K.x.Sun G.F.Quan Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Material Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China College of Materials Science and Engineering Sichuan University of Science and EngineeringZigong 643000China Department of Materials The University of ManchesterOxford RoadManchester M139PLUnited Kingdom

Aging prior to twinning deformation was proposed to alter the precipitate orientation of the plate-shapedβ-MgAlfrom(0002)basal planes(named basal plates)to■prismatic planes(named prismatic plates)in AZ31 Mg *** experimental results showed that the compressive yield strength(CyS)of the sample containing prismatic plates increased 40 MPa and the compression ratio raised by 22%compared to that containing basal *** underlying strengthening mechanism was analyzed via a yield strengthen(yS)model with a function of grain size,precipitate characters(size,oritention,fraction)and Schmid factor(SF).It revealed that the improvement of CyS was mainly attributed to the altered precipitate orientation and refined grain size produced by twinning ***,the prismatic plates always have a stronger hardening effect on basal slip than basal plates under the same varites of precipitate diameter and ***,the decreased CRSS ratio of prismatic slip to basal slip revealed that the activity of non-basal slip in Mg alloy might be *** activated slip systems provided more mobile dislocations,contributing to the large compression ratio of the Mg rolled sheet with prismatic plates.

关键词： Precipitate orientation Precipitation strengthening Grain boundary strengthening yield strength model

DyNAMIC TENSILE BEHAVIOR OF 5CrMnMo AT ELEVATED TEMPERATURES

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 521-527页

作者： W.Huang x.Nie x.Zan y.M.xia Department of Mechanical Engineering Key Laboratory of Mechanical Behavior and Design of Materials Hefei University of Science & Technology of China 230027 Hefei ChinaDepartment of Mechanical Engineering Key Laboratory of Mechanical Behavior and Design of Materials Hefei University of Science & Technology of China 230027 Hefei ChinaDepartment of Mechanical Engineering Key Laboratory of Mechanical Behavior and Design of Materials Hefei University of Science & Technology of China 230027 Hefei ChinaDepartment of Mechanical Engineering Key Laboratory of Mechanical Behavior and Design of Materials Hefei University of Science & Technology of China 230027 Hefei China

A new experimental technique has been developed for the performance of high temperature, high-strain rate tensile experiments in the self-designed tensile impact apparatus. This technique uses rapid contact heating method to heat the specimen to the desired temperature, thus avoids a significant temperature rise in incident and transmitted bars, and at the same time it is capable of retaining a nearly homogeneous temperature field within the specimen. As an illustration of its application, the high-temperature response of the forging die steel 5CrMnMo at high strain rates has been examined. Stress-strain curves are obtained for this material at strain rates ranging from 230s-1 to 1200s-1 and at temperature ranging from 25 to 600℃, respectively. For comparison, quasi-static experiments are performed over a slightly smaller range of temperatures.

关键词： elevated temperature strain rate tensile 5CrMnMo

Loading-unloading judgement for advanced plastic UH model

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2020年第4期36卷 827-839页

作者： x.Feng y.P.yao R.N.Li Z.Wan x.Dai College of Airport Civil Aviation University of ChinaTianjin 300300China School of Transportation Science and Engineering Beihang UniversityBeijing 100191China School of Automobile and Transportation Tianjin University of Technology and EducationTianjin 300222China Research Institute of Base and Foundation China Academy of Building ResearchBeijing 100013China

The unified hardening(UH)model proposed by yao et al.(Geotechnique 2009)is the constitutive model which can consider the influence of the complex stress path and stress history on the deformation and strength of clays ***,the loading-unloading criterion of material model is defined as the change law of the intersection of current yield surface and the p axis,which makes the loading-unloading in the process of hardening and softening can be unified considered in UH ***,the Newton-Raphson method is adopted to attain the nonlinear problems solution in the finite element method of UH model,and the semi-implicit return mapping method is adopted to update *** application of the UH model in the finite element is *** then,the analyses of triaxial test are performed using the unit prediction and finite element *** results of the unit prediction method are compared with the experimental results to illustrate the rationality of the UH *** the results with the unit prediction method and the finite element method,the correctness of the finite element program of the UH model is ***,Ae three-dimensional firdte element andysis of embankment on soft soil is performed by the *** comparison between the results calculated by the UH model and the modified Cam-clay(MCC)model and the experimental data shows that the UH model is rational in analyzing the actual embankment engineering on soft soil.

关键词： Over-consolidated clay Unified hardening model Loading-unloading judgement Finite element method Stress-strain

NONLINEAR DyNAMICS OF A FGM PLATE WITH TWO CLAMPED OPPOSITE EDGES AND TWO FREE EDGES

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

Acta Mechanica Solida Sinica 2014年第4期27卷 394-406页

作者： y.x.Hao W.Zhang J.yang College of Mechanical Engineering Beijing Information Science and Technology University College of Mechanical Engineering Beijing University of Technology School of Aerospace Mechanical and Manufacturing Engineering RMIT University PO Box 71Bundoora VIC 3083 Australia

This paper deals with the nonlinear forced vibration of FGM rectangular plate with a boundary of two edges clamped opposite and the other two free. The plate is subjected to transversal and in-plane excitations. The present research treats the material properties of the FGM plates as temperature-dependent and graded continuously throughout the thickness direction, following the volume fraction of the constituent materials according to the power law. The temperature is assumed to be constant in the plane and varied only in the thickness direction of the plate. In the framework of geometrical nonlinearity the plate is modeled and the equations of motion are obtained on Hamilton＇s principle. With the help of Galerkin discretization, the nonlinear ordinary differential equations describing transverse vibration of the plate are proposed. By the numerical method, the nonlinear dynamical responses of the FGM plate with two clamped opposite and two free edges are analyzed.

关键词： functionally graded materials plate clamped bifurcation

Shape Memory Epoxy Resin and Its Composites:From Materials to Applications

在线全文

学校读者我要写书评

暂无评论

Research 2022年第2期2022卷 345-369页

作者： Lan Luo Fenghua Zhang Jinsong leng Centre for Composite Materials and Structures Harbin Institute of Technology(HIT)Harbin 150080China

Shape memory polymers(SMPs)have historically attracted attention for their unique stimulation-responsive and variable stifness and have made notable progress in acrospace,civil industry,and other *** particular,epoxy resin(EP)has great potential due to its excellent mechanical properties,fatigue resistance,and radiation ***,we focus on the molecular design and network construction of shape memory epoxy resins(SMEPs)to provide opportunities for performance and functional *** and high-performance SMEPs are introduced in detail,including multiple SMEPs,two-way SMEPs,outstanding toughness,and termperature ***,emerging applications of SMEP's and their composites in aerospace,four-dimensional printing,and self-healing are *** on this,we point out the challenges ahead and how SMEPs can integrate performance and versatility to meet the needs of technological development.

关键词： composites printing resins

Correlation between test temperature, applied load and wear transition of Mg97Zn1y2 alloy

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

Journal of Magnesium and Alloys 2021年第2期9卷 592-603页

作者： J.An y.x.Tian C.Q.Feng Key Laboratory of Automobile Materials Ministry of EducationDepartment of Materials Science and EngineeringJilin UniversityChangchun 130025PR China

Dry sliding wear tests were performed on Mg97 Zn1 y2 alloy at various temperatures of 20,50,100,150 and 200°C using a pin-on-disc wear testing machine in order to reveal mild-severe(M-S)wear transition mechanism during elevated-temperature wear *** was shown that at each test temperature,the wear rate increased with increasing load,and all wear rate-load curves demonstrated two distinct stages *** and severe wear *** predominant wear mechanisms operating in mild and severe wear stages were analyzed,and they were indicated in the mild and severe wear regimes of a wear mechanism transition map,respectively.M-S wear transition mechanism was analyzed by comparison of microstructure transformation and hardness change in subsurfaces of samples tested in mild and severe wear stages,from which M-S wear transition mechanism was confirmed as softening of surface material arising from dynamic recrystallization(DRx)microstructure *** M-S wear transition load was found to have a linear relationship with test temperature,and decreased with rising test temperature.M-S wear transition obeyed a critical surface DRx temperature(SDT)criterion under given conditions,and the transition loads were estimated at various test temperatures by using the criterion.

关键词： Mg-alloys Elevated temperatures Wear rate Wear mechanism Wear transition

A comprehensive review of in-situ polymer gel simulation for conformance control

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2022年第1期19卷 189-202页

作者： Baojun Bai Jianqiao leng Mingzhen Wei Missouri University of Science and Technology Rolla65409USA

Gel treatment has been widely applied in mature oilfields to improve sweep efficiency and control water *** numerical simulation is of major importance to the optimization design and prediction of a successful gel ***,there exist many problems in current simulation studies in published *** paper first presents a comprehensive review on the major factors that have been considered at different gelation stages during gel treatment,the models used in the commercial/inhouse simulators,and current numerical simulation studies on both laboratory and field *** we classify the current in-situ gel numerical simulation problems as 1,deficient model problem that has published numerical model but has not been applied in simulator and application studies;2,missing model problem that does not have published quantitative model;and 3,inaccurate application problem that does not consider the major factors of gel performance,based on the reasons from some questionable results of current simulation ***,we point out the major research efforts that should be made in the future to better simulate in-situ gel treatment *** review indicates that numerous simulation studies using commercial software packages intend to predigest the gel treatment,many of which,however,ignore important mechanisms and mislead the operation of gel *** fact,a full assessment of simulating in-situ gels cannot be achieved unless the quantitative models can be qualified in terms of transport and plugging mechanisms based on the experimental results.

关键词： In-situ gel Mechanism Simulation model Application studies

Damage to aircraft composite structures caused by directed energy system: A literature review

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第4期17卷 1269-1288页

作者： y.x.Zhang Zhi Zhu Richardson Joseph Isfakul Jamal Shihan School of Engineering Western Sydney UniversityKingswoodNSW2751Australia

This paper presents a comprehensive review of the research studies on direct energy system effect on aircraft composite structures to develop a good understanding of state-of-the-art research and development in this *** review begins with the application of composite materials in the aircraft structures and highlights their particular areas of application and *** overview of directed energy system is *** of the commonly used systems in this category are discussed and the working principles of laser energy systems are *** experimental and numerical studies reported regarding the aircraft composite structures subject to the effect of directed energy systems,especially the laser systems are reviewed in *** particularly,the general effects of laser systems and the relevant damage mechanisms against the composite structures are *** review draws attention to the recent research and findings in this field and is expected to guide engineers/researchers in future theoretical,numerical,and experimental studies.

关键词： Aircraft Composite structures Damage mechanisms Direct energy system Laser system Experiment Numerical studies

Build a two-way road for health industry: the current circumstance of translational medicine in China

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2012年第10期55卷 931-932页

作者： leng FangWei Institute of Biophysies Chinese Academy of SciencesBeijing 100101China

Translational medicine is a new emerging medical practice comprising multidisciplinary research from basic sciences to clinical medicine. It is regarded as a two-way road： bench to bedside and bedside to bench, playing important roles in communications between basic and clinical scientists [1]. As a developing country with more than 1.3 billion people, China bears a complex disease spectrum. It is thus urgent for China to develop translational medicine to facilitate pre- diction, prevention, diagnosis, and treatment of diseases. With the energetic supports of governments and scientists, translational medicine in China has developed rapidly in recent years. The 12th issue of Science China Life Sciences in 2011 organizes a special issue--Translational medicine in China I： Perspectives from Chinese physicians and scien- tists [2], focusing on translational medicine in China with five reviews, making a comprehensive introduction to the current circumstance of translational medicine in China.

关键词：中国医学转化健康产业基础科学科学家生命科学疾病谱