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1.
EigenAnalysisforBalanceStatesofCombiningSystemsofCableSupportingMechanismwithCableChenNan(陈南)(DepartmentofMechanicalEnginee...  相似文献   

2.
DynamicGraphicalSimulationofaLargeScaleMotorCraneChassisChenYunfeia(陈云飞)HuangXishib(黄锡时)XuShangxiana(许尚贤)(aDepartmentofMechan...  相似文献   

3.
ARandomMultiAccessMethodforDataServicesinCDMACelularSystemLiZhen(李振)YouXiaohu(尤肖虎)(NationalMobileCommunicationsResearchLabor...  相似文献   

4.
ResearchonFaultDiagnosticClassifierZhaoLindu1(赵林度)HuaChangchun2(花长春)ShengZhaohan1(盛昭瀚)1(DevelopmentResearchCenterofSystemsand...  相似文献   

5.
High-PerformanceNetworkCommunicationsforCSCWSongJun(宋军)GuGuanqun(顾冠群)(DepartmentofComputerScienceandEngineering,SoutheastUni...  相似文献   

6.
听力部分Ⅰ 从A、B、C中选出你所听到的单词并将代表答案的字母填入前面的括号中(5分)()1 AnightBlightClate()2 AleaveBnewClove()3 AwashBwhichCwatch()4 AmiddleBlittleCtable()5 AsupperBsoldierCtableⅡ 根据所听对话及问题 ,选择正确答案(5分)()1 AShestudiesinChina.BSheteachesinChina.CSheisateacher.()2 AShecomesfromCana…  相似文献   

7.
DOCSISTX1IntroductionInJanuary1996,cablecompaniesandmanufac-turesinNorthAmericaestablishedMCNS(Multime-diaCableNetworkSystemPa...  相似文献   

8.
RemoteCommunicationandControlofaRobotUsingMMSDingXinquan(丁心泉)(DepartmentofComputerScienceandEngineering,SoutheastUniversity,...  相似文献   

9.
1995年全国各级成人学校基本情况BasicStatisticsofAdultSchoolsinChinabyLevel&Typein10thousand(A):ofthetotal:TheRegularShort-CycleCoursesinRad...  相似文献   

10.
全国各级成人学校基本情况BasicStatisticsofAdultSchoolsinChinabyLevel&Type¥//(A):Ofthetotal:TheRegularShort-CycleCoursesinRadio/TVUniversit...  相似文献   

11.
FlexuralBehaviourofHigh-StrengthSteelFiber-ReinforcedConcreteBeamsQianChunxiang(钱春香)(DepartmentofMaterialsScienceandEngineeri...  相似文献   

12.
To study the bonding properties between steel strand and concrete at room and cryogenic temperatures, a series of center pullout experiments were conducted on 96 bonding anchorage specimens at the lowest temperature of-165 ℃. The impacts on the bonding property of such parameters as the temperature, concrete strength, the relative concrete cover thickness, and the relative anchorage length were analyzed. The test results indicate that the changes in temperature have a clear effect on the bonding property between steel strand and concrete. As the temperature decreases, the bond stress, which corresponds to a 1 mm slip of steel strand in relation to concrete, and the ultimate bond strength initially increase and subsequently decrease at the inflection point of-80 ℃. The impact of the concrete strength on the bonding property, as shown by the tensile strength and the moisture content interaction, indicates that the bond stress vs concrete strength curve initially increases and later decreases with a decrease in temperature; the bond stress vs concrete cover thickness curve linearly increases, but the bond stress vs anchorage length curve linearly decreases at first and finally levels off.  相似文献   

13.
Performance of cross-shaped concrete columns confined by stirrups   总被引:1,自引:0,他引:1  
The stress-strain curves of confined concrete were obtained based on tests of seven cross-shaped columns confined by stirrups under axial load. The experiment results showed that the strength and deformation of confined concrete can be enhanced effectively by stirrups for cross-shaped columns. Compared with the non-confined concrete, when the stirrup characteristic value is in the range of 0.046--0.230, the confined concrete compressive strengths has an increase of 8%--43%, and the strain corresponding to the peak stress of confined concrete has an increase of 25%-- 195%. According to the test results, the effects of stirrup characteristic and stirrup spacing on the compressive strength and strain of confined concrete were analysed. It is shown that the compressive strength of confined concrete has a linear relationship with the product of stirrup characteristic value and stirrup effective restraint coefficient, and the strain corresponding to the peak stress of confined concrete has a nonlinear relationship with the product of stirrup characteristic value and stirrup effective restraint coefficient. The stress-strain curve equation of confined concrete was proposed for cross-shaped columns, and the calculated curves are in good agreement with the experimental curves.  相似文献   

14.
A new type of green reactive powder concrete (GRPC) with compressive strength of 200 MPa is prepared by utilizing composite mineral admixtures, natural fine aggregates, and short and fine steel fibers. The quasi-static mechanical properties (mechanical strength, toughness, fracture energy and interfacial bonding strength) of GRPC specimens, cured in three different types of regimes, are investigated. The experimental results show that the mechanical properties of the C200 GRPC made with the powder binders that is composed of 40% of Portland cement, 25% of ultra fine slag, 25% of ultra fine fly ash and 10% of silica fume are better than the others'. The corresponding compressive strength, flexural strength and fracture energy are more than 200 MPa, and 30 000 J/ m2 respectively. The dynamic tensile behavior of the C200 GRPC is also investigated through the split Hopkinson pressure bar (SHPB) according to the spalling phenomenon. The dynamic testing results demonstrate that strain rate has an important effect on the dynamic tensile behavior of GRPC. With the increase of strain rate, its peak stress and relevant strain increase. The GRPC exhibits an excellent strain ratio stiffening effect under the dynamic tensile load with high strain ratio, resulting in a significant change of the fracture pattern.  相似文献   

15.
为了能够更好地分析混凝土收缩对钢-混凝土组合梁内力的影响,在混凝土自身收缩特性的基础上,分析了钢-混凝土组合梁的混凝土收缩应变特性,从而得出凝土收缩引起的钢-混凝土组合梁的内力计算公式,并由此分析了混凝土收缩引起的内力对组合梁产生的混凝土板提前开裂、挠度增加等直接影响。  相似文献   

16.
In this study, the effect of steel fibers coated with chemically reactive enamel (CRE) on the system response of concrete structures with reinforcing bars has been investigated for the first time. In particular, the ultimate strength, ductility, and failure mechanism of 24 reinforced concrete slabs were experimentally characterized under static and blast loads. CRE coating applied on steel bars reduced the crater area of slabs under blast loads by up to 20%; it slightly increased the strength of slabs and significantly reduced the strength degradation of slabs when increasingly deflected under static loads, making the slabs more ductile. CRE coating applied on steel fibers increased the strength of slabs by up to 16% under static loads. The influence of CRE coating applied on both steel fibers and bars may be taken into account by introducing a coating factor in the range of 0.57<β<1.0 in the American Concrete Institute (ACI) development length equation.  相似文献   

17.
INTRODUCTION A number of experimental fatigue studies were conducted on plain concrete as well as on steel fibre reinforced concrete (SFRC) beams of different sizes under different loading conditions. Murdock and Kesler (1958) investigated the effect of stress ratio on the fatigue strength of plain concrete. Batson et al.(1972) reported fatigue strength of 74% and 83% of the first crack static flexural strength at 2 million cycles of complete reversed and not-reversed loads respectively…  相似文献   

18.
基于 8个碳纤维布约束高强混凝土棱柱体试件的试验 ,研究了碳纤维布对提高高强混凝土抗压强度和改善其变形性能的作用 .试验发现 ,包裹碳纤维布可以提高试件的抗压强度 ,并有效地改善混凝土的变形性能 ,其效果随碳纤维用量的增加而更加显著 .在试验基础上 ,根据理论分析和对试验结果的整理 ,归纳出碳纤维布约束高强混凝土的应力 应变全曲线方程 .最后 ,利用提出的全曲线方程编制计算机程序 ,分析了包裹碳纤维布对提高高强混凝土压弯构件的强度和延性的作用  相似文献   

19.
We proposed a bilinearity constitutive curve model of fiber reinforced polymer (FRP) confined concrete which includes a parabola in the first stage and a straight line in the second stage. The FRP-confined concrete has powerful confinement status and weak confinement status leading to different equations of parabola. We analyzed the impacts of factors such as confinement ratio and restrain stiffness on confined concrete compressive strength, ultimate strain and other control parameters through finite element analysis. The results show that the confinement ratio determines the confinement status, and the increase of the confinement ratio has a limited capacity to increase the compressive strength, The deformation of confined concrete is influenced by restrain stiffness. The stronger the restrain stiffness is, the less the lateral deformation is and the greater ultimate axial strain will be. The consideration of equivalent section coefficient kse is needed in the non-circular section confined concrete. We analyzed the results and proposed boundary values of strong and weak confinement styles, a peak/inflection point stress and strain model, and a compressive strength and ultimate strain model.  相似文献   

20.
大骨料混凝土在双轴压应力状态下的变形和强度试验研究   总被引:1,自引:0,他引:1  
利用大连理工大学自行研制改造的液压伺服静、动态三轴试验系统对不同骨料级配和尺寸的混凝土试件在双向压荷载作用下的变形和强度特性进行了试验研究.试验所用试件有3种:采用大坝原级配最大骨料粒径为80 mm的立方体试件以及相应的湿筛混凝土试件,尺寸分别为250mm×250mm×250 mm,150 mm×150 mm×150 mm和100 mm×100 mm×100 mm.试验过程中,测得了所有试件两个加载方向的应力和应变,以及未加载方向上的侧向变形,并根据试验结果,系统地探讨了不同级配混凝土的双轴抗压强度、极限变形、应力-应变曲线以及破坏形态的变化规律,发现大骨料混凝土在双轴压作用下的极限强度和变形能力要比相应的湿筛小骨料混凝土提高的更多,最后分别在主应力空间和主应变空间建立了不同级配混凝土的破坏准则,这为水工大体积混凝土按多轴强度理论进行设计提供了试验依据.  相似文献   

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