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1.
In-SituEpitaxialGrowthofBi-Sr-Ca-Cu-OSuperconductingThinFilmsonSi(100)byrfOf-AxisMagnetronSputeringQianWensheng(钱文生)LiuRong(刘...  相似文献   

2.
LOCALINFLUENCEANALYSISBASEDONTHEK-LDISTANCEANDTHEINFORMATIONDISTANCEHuYueqing(胡跃清)(DepartmentofMathematicsandmechanics)LOCALI...  相似文献   

3.
On-LineIdentificationofGrindingBurnandWheelWearBasedonGrindingChipsThermalFlowShiJinfei(史金飞)ZhangXiaoling(张晓玲)ZhongBinglin(钟...  相似文献   

4.
THESTABILITYOFSOLID-LIQUIDINTERFACEOFUNIDIRECTIONALSOLIDIFIEDFe-CEUTECTICALLOYJiangJianqing(蒋建清)(DepartmentofMaterialSciencea...  相似文献   

5.
StudyonLong-DistanceDistributedMachineConditionMonitoringandFaultDiagnosisSystemJiaMinping(贾民平)ZhongBinglin(钟秉林)(Departmento...  相似文献   

6.
INFLUENCEOFUNBALANCEONLOW-FREQUENCYVIBRATIONOFROTOR-BEARINGSYSTEMYansJiansang(杨建刚);DaiDecheng(戴德成);GaoWei(高伟)(ResearchInstitu...  相似文献   

7.
ABIFURCATIONANALYSISOFTHESTEADY-STATEMODELFORAMULTIJUNCTIONDEVICECaoJuncheng(曹俊诚);WeiTongli(魏同立)(MicroelectronicsCenter)WangY...  相似文献   

8.
StressAnalysisoftheGlassBulbof35-inch(V)120°ColorPictureTubeTorongeyPeterKimanus(MoiUniversity,DepartmentofPhysics,P.O.Box390...  相似文献   

9.
RejectionofNarowBandInterferenceinDSSpreadSpectrumSystemsUsingRecurentNeuralNetworksYouXiaohu(尤肖虎)FuLi(傅莉)(NationalCommunic...  相似文献   

10.
High-PerformanceNetworkCommunicationsforCSCWSongJun(宋军)GuGuanqun(顾冠群)(DepartmentofComputerScienceandEngineering,SoutheastUni...  相似文献   

11.
采用Ansys有限元软件对8根不同锈蚀率的FRP片材加固钢筋混凝土梁的受弯性能进行数值分析,研究纵筋锈蚀率对FRP加固梁的裂纹开展、破坏模式、承载能力以及延性和变形能力的影响.研究结果表明:低钢筋锈蚀率的梁发生受压区混凝土压碎破坏;中等锈蚀率的梁钢筋屈服后,钢筋与混凝土界面发生黏结滑移,最后FRP剥离破坏;高锈蚀率的梁钢筋没有达到屈服强度便发生黏结滑移,最后发生受压区混凝土压碎破坏.钢筋锈蚀越严重,FRP加固钢筋混凝土梁的承载力降低得越多.试件RCB-1(锈蚀率为0)的承载力为115 kN,而试件RCB-7(锈蚀率为20%)的承载力仅为42 kN.与FRP加固未锈蚀的钢筋混凝土梁相比,FRP加固锈蚀钢筋混凝土梁的变形能力较高.试件RCB-1和试件RCB-7的最大跨中挠度分别为20 mm和35 mm,而试件RCB-5(锈蚀率为10%)的最大跨中挠度达到了60 mm.  相似文献   

12.
Experimental study on behaviors of polypropylene fibrous concrete beams   总被引:1,自引:0,他引:1  
Synthetic fibers made from nylon or polypropylene have gained application when loose and woven into geo textile form although no information on the matrix's mechanical performance is obtained so that more understanding of their structural contribution to resist cracking can be determined. This paper presents the results of an experimental investigation to determine the performance characteristics of concrete reinforced with a polypropylene structural fiber. In this investigation "Fiber mesh" brand of fibers manufactured by SL Concrete System, Tennessee, USA and marketed by M/S Millennium Building System, Inc., Bangalore, India are used. The lengths of the fibers used were 24 mm. Fiber dosages used were 0.9, 1.8, 2.7 kg/m^3. A total of three mixtures, one for each fiber dosage were made. A standard slump cone test was conducted on the fresh concrete mix with and without fibers to determine the workability of the mix. The test program included the evaluation of hardened concrete properties such as compressive, split tensile, modulus of rupture and flexural strengths. The increase in compressive strength is about 36.25%, 26.20%, and 23.75% respectively that of plain concrete. This increase in strength was directly proportional to amount of fibers present in the mix. The increase in flexural strength for Mixes I-III is about 21%, 16.6%, and 23% respectively that of plain concrete specimens. An experimental investigation was also made to study the behaviors of reinforced fibers concrete beams (with longitudinal reinforcements) under two-point loading. The deflection and crack patterns were also studied. The improvements in strength and ductility characteristics were discussed.  相似文献   

13.
Carbon fiber reinforced polymer(CFRP)bars were prestressed for the structural strengthening of 8 T-shaped rein-forced concrete (RC)beams of a 21-year-old bridge in China.The ultimate bearing capacity of the existing bridge after retrofit was discussed on the basis of concrete structures theory.The flexural strengths of RC beams strengthened with CFRP bars were controlled by the failure of concrete in compression and a prestressing method was applied in the retrofit.The field construction processes of strengthening with CFRP bars-including grouting cracks,cutting groove,grouting epoxy and embedding CFRP bars,surface treating,banding with the U-type CFRP sheets,releasing external prestressed steel tendons-were introduced in detail.In order to evaluate the effectiveness of this strengthening method,field tests using vehicles as live load were applied before and after the retrofit.The test results of deflection and concrete strain of the T-shaped beams with and without strengthening show that the capacity of the repaired bridge,including the bending strength and stiffness,is enhanced.The measurements of crack width also indicate that this strengthening method can enhance the durability of bridges.Therefore,the proposed strengthening technology is feasible and effective.  相似文献   

14.
INTRODUCTION Externally bonded fiber reinforced polymer (FRP) composites can be used to improve the flexural strength of structural members. To evaluate the flex-ural performance of the strengthened members, it is necessary to study the flexural stiffness of FRP- strengthened RC members at different stages, such as pre-cracking, post-cracking and post-yielding. Up to now, only very few studies were focused on the structural members strengthened under pre-loading or pre-cracking (Arduin…  相似文献   

15.
PropertiesofHighStrengthSteelFiberReinforcedConcreteunderCompressionQianChunxiang(钱春香)(DepartmentofMaterialsScienceandEnginee...  相似文献   

16.
Prestressed steel ultrahigh-strength reinforced concrete (PSURC) beam is a new type of prestressed concrete beam, which not only has a considerable compressive strength attributed to the ultrahigh strength concrete, but also ensures a certain degree of ductility at failure due to the existence of structural steel. Five of these beams were monotonically tested until shear failure to investigate the static shear performance including the failure pattern, load-deflection behavior, shear capacity, shear crack width and shear ductility. The experimental results show that these beams have superior shear capacity, crack control ability and shear ductility. To study the shear performance under repeated overloading, seven PSURC beams were loaded in cyclic test simultaneously. The overall shear performance of cycled beams is similar to that of uncycled beams at low load level but different at high load level. The shear capacity and crack control ability of cycled beams at high load level are reduced, whereas the shear ductility is improved. In addition, the influences of variables including the degree of prestress, stirrup ratio and load level on the shear performance of both uncycled and cycled beams were also discussed and compared, respectively.  相似文献   

17.
二次受力下碳纤维布加固梁抗弯性能试验研究   总被引:1,自引:0,他引:1  
进行了4根不同二次受力条件下碳纤维布加固的钢筋混凝土梁和1根对比混凝土梁的抗弯性能试验研究。试验及分析结果表明,用粘贴碳纤维布的方法来提高梁的承载力十分有效,且预加载的存在使加固梁的极限荷载降低;碳纤维布能有效约束裂缝的开展,但裂缝的数量增加和分布区域变大,且预加载的大小会影响加固梁裂缝的开展和分布;碳纤维布加固可以增强梁的刚度,但延性有所降低。  相似文献   

18.
Carbon fiber reinforced polymer (CFRP) bars were prestressed for the structural strengthening of 8 T-shaped reinforced concrete (RC) beams of a 21-year-old bridge in China. The ultimate bearing capacity of the existing bridge after retrofit was discussed on the basis of concrete structures theory. The flexural strengths of RC beams strengthened with CFRP bars were controlled by the failure of concrete in compression and a prestressing method was applied in the retrofit. The field construction processes of strengthening with CFRP bars including grouting cracks, cutting groove, grouting epoxy and embedding CFRP bars, surface treating, banding with the U-type CFRP sheets, releasing external prestressed steel tendons-were introduced in detail. In order to evaluate the effectiveness of this strengthening method, field tests using vehicles as live load were applied before and after the retrofit. The test results of deflection and concrete strain of the T-shaped beams with and without strengthening show that the capacity of the repaired bridge, including the bending strength and stiffness, is enhanced. The measurements of crack width also indicate that this strengthening method can enhance the durability of bridges. Therefore, the proposed strengthening technology is feasible and effective.  相似文献   

19.
为了研究钢筋增强ECC梁受弯性能,进行了钢筋增强ECC梁和普通钢筋混凝土梁受弯的对比研究.结果表明,相比普通钢筋混凝土梁,钢筋增强ECC梁的受弯承载力和延性分别提高了24.8%和187.76%,并且在梁中用ECC代替混凝土可有效延缓裂缝的发展.此外,采用简化的ECC本构模型对钢筋增强ECC及混凝土梁的受弯性能进行了非线性有限元分析,模拟结果与试验结果吻合较好,在服役期间钢筋增强ECC梁的裂缝可以控制在0.4 mm以下.ECC材料的使用可明显提高梁的抗弯承载力、变形能力、延性等受弯性能.  相似文献   

20.
INTRODUCTION The aging or deterioration of existing R. C.(reinforced concrete) or P. C. (prestressed concrete)structures is one of the major problems that modernengineers have to face. If the flexural or shear strengthof R. C. or P. C. structures is not sufficient to maintaintheir service functions, strengthening of these struc-tures becomes necessary. To date, steel plates havebeen used to strengthen concrete members. Usingcomposite plates to strengthen R.C. or P.C. structures…  相似文献   

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