检索结果-南通市图书馆

Experimental investigation of seismic performance of concrete-filled glass fiber reinforced polymer tubular columns

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 Harbin Institute of Technology(New Series) 2011年第5期18卷 37-43页

作者：关宏波王清湘 State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology College of Civil Engineering and Architecture Liaoning Technical University

A reinforced concrete (RC) column and four concrete filled GFRP tubular columns,which are subjected to combined axial compression and lateral cycle loading,were tested in order to investigate the seismic performance of composite construction concrete filled glass fiber reinforced polymer (GFRP) tubular (CFFT) *** results indicated that concrete-filled GFRP tubular columns exhibit considerable influence over the seismic performance of columns by providing hoop confinement to the core *** concrete filled GFRP tubular columns exhibit significant improvement over traditional RC columns in both ultimate strength and *** column-footing connection modes do not affect the strength and ductility of concrete filled GFRP tubular *** strength of concrete filled GFRP tubular columns under high axial compression load conditions are slightly increased,however,ductility declined.

关键词： concrete columns connections ductility concrete filled GFRP tubular column seismic

Stability Performance of Buckling-Restrained Brace with Brace Joints

在线全文

学校读者我要写书评

暂无评论

Transactions of Tianjin University 2010年第2期16卷 81-88页

作者：贾明明张素梅吕大刚 School of Civil Engineering Harbin Institute of Technology

The stability and ductility of four buckling-restrained braces (BRBs) with brace joints were studied. The load-carrying element of BRB was fabricated with steel (Chinese Q235), and a layer of colloidal silica sheet (0.5 mm in thickness) or four layers of plastic film (0.2 mm in thickness) were used as unbonding materials to provide space to prevent the buckling of inner core in higher modes and facilitate its lateral expansion in case of compression. Based on the equation of BRBs with brace joints of different restrained stiffnesses, the buckling load is calculated considering the initial geometric imperfections and residual stress, and the theoretical values agree well with the experiment results. It is concluded that the buckling load and ductility of BRBs are influenced greatly by the restrained stiffness of brace joints. If the restrained stiffness is deficient, the unstrained segment of BRBs with less stiffness will buckle firstly. As a result, the ultimate load of BRBs decreases, and the maximum compression load is reduced to about 65% of the maximum tension load; the stiffness also degenerates, and there is a long decreasing stage on the back-bone curve in compression phase; the ductility decreases, i.e., the ultimate tension ductility and ultimate compression ductility are approximately 15 and 1.3 respectively, and the cumulative plastic ductility is only approximately 200. If the restrained stiffness of joint is large enough, the stability will be improved as follows: the yielding strength and ultimate strength of BRBs are nearly the same, and there is an obvious strain intensification in both tension and compression phases; the ductility of brace also increases obviously, i.e., the ultimate tension ductility and ultimate compression ductility are both approximately 14, and the cumulative plastic ductility reaches 782.

关键词： buckling-restrained braces joint ends restrained stiffness buckling load stability performance ductility

Effect of Microalloying Additions on the Microstructure and Mechanical Properties of Low Carbon Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S1期18卷 246-251页

作者： EISSA Mamdouh ABD El-Aziz Ahmed GHALI Saeed HALFA Hossam SABER Shady Central Metallurgical Research & Development Institute "CMRDI" Faculty of Material Science and Engineering German University in Cairo "GUC"

Low carbon steels are characterized by good weldability,formability and fracture toughness ***,the low strength levels of these steel grades limit their wide *** the other hand,increasing the strength by increasing the carbon content and alloying elements deteriorates the other *** this study,the microalloying technique was used to examine the possibility of attaining low carbon steels with good combination of strength,ductility and impact properties.A low carbon steel microalloyed with single addition of vanadium and another one microalloyed with combined addition of vanadium and titanium were used in this investigation and their properties were compared with non-microalloyed low carbon steel having the same base ***,other two nonmicroalloyed and V-microalloyed steels with higher carbon,silicon and manganese contents were also investigated to reveal the effect of base ***,hardness,room and zero temperature Charpy V-notch impact tests were conducted to evaluate the variations in the mechanical properties of low carbon hot forged steel containing vanadium and combinations of vanadium and *** addition,the microstructures of the different investigated steels were observed using both optical microscope and scanning electron ***,the hardness of the ferrite phase was also determined using micro-hardness *** results showed improvement of the mechanical properties of the investigated steels by both single V-and combined V + ***,hardness and impact tests results indicated that good combinations of strength,ductility and impact properties can be achieved by V-microalloying *** with combination of V and Ti microaddition has much higher hardness,yield strength,ultimate tensile strength and impact energy at both room and zero temperatures compared with non-microalloyed and single Vmicroalloyed *** C,Si and Mn contents result in

关键词： low carbon steels single microalloying combined microalloying strength ductility impact energy grain refinement precipitation strengthening

Literature review on the mechanical properties of materials after surface mechanical attrition treatment(SMAT)

在线全文

学校读者我要写书评

暂无评论

Nano Materials Science 2020年第1期2卷 3-31页

作者： Temitope Olumide Olugbade Jian Lu Department of Mechanical Engineering City University of Hong KongHong Kong SARChina Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM) City University of Hong KongHong KongChina Centre for Advanced Structural Materials City University of Hong Kong Shenzhen Research InstituteGreater Bay Joint DivisionShenyang National Laboratory for Materials ScienceShenzhenChina

Most of the challenges experienced by many engineering materials originate from the surface which later leads to total failure,hence affecting the resultant mechanical properties and service ***,these challenges have been addressed thanks to the invention of a novel surface mechanical attrition treatment(SMAT)method which protects the material surface by generating a gradient-structured layer with improved strength and hardness without jeopardizing the *** present work provides a comprehensive literature review on the mechanical properties of materials after SMAT including the hardness,tensile strength and elongation,and residual ***,a brief introduction on the different forms of surface nanocrystallization is given to get a better understanding of the SMAT process and its advantages over other forms of surface treatments,and then the grain refinement mechanisms of materials by SMAT from the matrix region(base material)to the nanocrystallized layer are *** effects of fatigue,fracture,and wear of materials by the enhanced mechanical properties after SMAT are also discussed in *** addition,the various applications of SMAT ranging from automotive,photoelectric conversion,biomedical,diffusion,and 3 D-printing of materials are extensively *** prospects and recent research trends in terms of mechanical properties of materials affected by SMAT are then summarized.

关键词： SMAT Nanostructured materials Ultra-high strength ductility Fatigue

Flexural behaviors of double-reinforced ECC beams

在线全文

学校读者我要写书评

暂无评论

Journal of Southeast University(English Edition) 2013年第1期29卷 66-72页

作者：颜嫄许赟汪逊潘金龙东南大学混凝土及预应力混凝土结构教育部重点实验室南京210096

In order to investigate the flexural behaviors of engineered cementitious composites （ECC）, theoretical and experimental researches are done on flexural doublereinforced ECC beams. Based on the assumption of the plane section remaining plane in bending and simplified constitutive models of materials, the calculation methods of load carrying capacities for different critical stages are obtained. Then, these calculation methods are demonstrated by comparing the test results with the calculation results. Finally, based on the proposed theoretical formulae, the effects of the compression strength, compression strain and tension strength of ECC, and the reinforcement ratio on the flexural behaviors of double-reinforced ECC beams are analyzed. The calculated and measured results are in good agreement, which indicates that the theoretical model can be used to predict the momentcurvature response of steel reinforced ECC beams. And the results of parametric studies show that the increase in the compression strength of ECC can greatly improve the flexural performance of beams; the increase in the ultimate compression strain can significantly improve the ultimate curvature and ductility, but has little effect on the load bearing capacity of beams. little effect on the flexural The tensile strength of ECC has behaviors of ECC beams. The increase in the steel reinforcement ratio can lead to significant improvement of the load bearing capacity and the stiffness of beams, but a degradation of the ductility of beams. The theoretical model and parameter analysis results in this paper are instructive for the design of steel reinforced ECC beams.

关键词： engineered cementitious composites (ECC) ultimate carrying capacity ultimate curvature ductility parametric study

Study of the Microstructure and Properties of ER70S-6 Wire Rods

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S1期18卷 929-932页

作者： HUANG Zhi-jun,WANG Yu-tao,XIONG Yan (Products Research Institute,R and D Center of Wuhan Iron and Steel (Group) Corporation,Wuhan 430080,Hubei,China) Wuhan Iron & Steel Grp Corp R&D Ctr Prod Res Inst Wuhan 430080 Hubei Peoples R China

After rolling even after drawing,a fraction of martensite may occur in the microstructure of ER70S-6 wire deteriorating the ductility and drawing *** mid-products of drawing for test were heat treated at 350℃ and 500℃,deformed ferrite plus pearlite plus some unchanged martensite and deformed ferrite plus pearlite plus troostite were obtained *** bending test was carried out on both as-drawn and heat-treated *** results showed that the brittleness of the as-drawn rods is not due to defects but due to the presence of martensite in *** sample heat-treated at 500℃ and cooled in oven has the best ductility.

关键词： ER70S-6 microstructure heat treatment ductility

Effect of rare earth elements on the microstructure and property for magnesium alloy AM60B

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2002年第6期9卷 466-469页

作者： KaikunWang KuiZhang 等 MaterialsSceienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China BeijingGeneralInstituteforNon－FerrousMetals Beijing100088China

The effects of rare earth elements on the microstructure and properties ofmagnesium alloy AM60B alloy were studied. Different proportions of rare earth elements were added toAM60B and the tensile tests were carried out under different temperatures. The experimental resultsshow that at room temperature the tensile strength of AM60B can be improved with the addition ofrare earth elements. The ductility of which at room or elevated temperature (120 deg C) can also beimproved, and the ductility is to some extent in proportion with the amount of rare earth *** ductility at 120 deg C is better than that at room temperature. The microstructure graphsdemonstrate that appropriate amount of rare earth elements (0.1 percent-0.2 percent, mass fraction)can fine AM60B's grain and improve its ductility.

关键词： magnesium alloy AM60B rare earth elements strength ductility microstructure

Modeling of semi-rigid beam-to-column steel joints under extreme loading

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2013年第3期7卷 245-263页

作者： C FANG B A IZZUDDIN A Y ELGHAZOULI D A NETHERCOT Department of Civil&Environmental Engineering Imperial College LondonLondon SW72AZUnited Kingdom

Joints play an important role in providing ductility for steel-composite structures subject to extreme loading conditions,such as blast,fire and *** to sound energy dissipation capability and fabrication efficiency,semi-rigid joints have increasingly received attention during the last *** paper presents a component approach for modeling semi-rigid beam-to-column joints based on Eurocode3,where the post-elastic response,including component strain hardening and ultimate rotational capacity,is also *** criteria are defined based on the ultimate deformation capacity of components and *** model enables a direct integration of joint response into global frame models with the consideration of axial deformability,such that the interaction between bending moment and axial force within the joints can be realistically *** addition,elevated temperature can be considered in the joint model via the degradation of the component *** comparisons with available test data,the joint model is shown to have good accuracy,and the failure criteria are found to be reliable yet *** strain hardening response of components is shown to have significant influence on the ultimate bending capacity of the joints,while neglecting it usually leads to a conservative prediction.

关键词： semi-rigid joint component method ductility elevated temperature

Ultimate Strength of Completely Overlapped Joint for Fixed Offshore Wind Turbine Jacket Substructures

在线全文

学校读者我要写书评

暂无评论

Journal of Marine Science and Application 2019年第1期18卷 99-113页

作者： Wie Min Gho Ye Yang Maritime Production Research Pte.Ltd School of Civil and Environmental Engineering Nanyang Technological University Global Maritime Consultancy Ltd

This paper presents an innovative eccentric jacket substructure for offshore wind turbines to better withstand intense environmental forces and to replace conventional X-braced jackets in seismically active areas. The proposed eccentric jacket comprises of completely overlapped joint at every joint connection. The joint consists of a chord and two braces in a single plane. The two braces are fully overlapped with a short segment of the diagonal brace welded directly onto the chord. The characteristic feature of this joint configuration is that the short segment member can be designed to absorb and dissipate energy under cyclic load excitation. The experimental and numerical study revealed that the completely overlapped joint performed better in terms of strength resistance, stiffness, ductility, and energy absorption capacity than the conventional gap joints commonly found in typical X-braced jacket framings. The eccentric jacket could also be designed to becoming less stiff, with an inelastic yielding and local buckling of short segment member, so as to better resist the cyclic load generated from intense environmental forces and earthquake. From the design economics, the eccentric jacket provided a more straightforward fabrication with reduced number of welded joints and shorter thicker wall cans than the conventional X-braced jacket. It can therefore be concluded based on the results presented in the study that by designing the short segment member in accordance with strength and ductility requirement,the eccentric jacket substructure supporting the wind turbine could be made to remain stable under gravity loads and to sustain a significantly large amount of motion in the event of rare and intense earthquake or environmental forces, without collapsing.

关键词： Offshore wind turbine Jacket substructure Eccentric jacket Completely overlapped joint Ultimate strength Cyclic loading ductility Energy absorption