【作者】 蔡新江；

【导师】 田石柱；

【作者基本信息】 哈尔滨工业大学 ， 防灾减灾工程及防护工程， 2010， 博士

【摘要】 混合试验源于子结构拟动力试验,是一种集物理试验与数值模拟于一体的先进抗震试验方法,可以对结构进行类似于有限元的精细化计算分析,借助于互联网技术可以形成功能强大的“网络协同混合试验方法”,此方法是目前国际土木工程学术界的热点前沿课题,国内外多个研究机构已经对此进行了相应的基础性研究。基于实验室现有的试验资源和计算资源,本文针对混合试验方法的基本理论及其在多跨桥中的应用展开研究,主要内容如下:1.与传统的子结构拟动力试验方法相比较,指出混合试验方法的最大优势在于模型中集成了多个非线性试验单元,从而可以对结构进行更为精细化的整体分析而非单独的构件分析,并且可以基于互联网技术将异地分布的多个结构实验室连接起来协作进行大比例或足尺结构试验,从而共同开展更为复杂结构的抗震试验研究。2.针对土木工程中广泛应用的MTS结构试验系统,基于FlexTest GT控制器及MTS 793系列控制软件,提出了一种基于内部命令控制的混合试验方法,利用VB_COM接口程序控制输入输出,实现对GT控制器的控制,进一步开发了三个程序:站监测程序、正弦波加载程序和斜坡加载程序,并将斜坡加载程序嵌入NetSLab-Tester中,通过建立一个Master-Slaver网络进行了MTS与NetSLab之间的对接集成。在实验室局域网范围内进行了一根悬臂钢柱的验证试验,试验结果表明:该方法简化了试验连接并提高了速度,为混合试验研究提供了一种新方法,但对试验系统硬件和软件提出较高的要求,并且Master-Slaver网络可以有效地起到保护系统操作计算机的目的。3.针对多跨桥混合试验中一个柱试验单元,设计了4个钢筋混凝土短柱模型,基于M. J. N. Priestley et al抗剪承载力设计方法进行了FRP加固计算,并进行了各种材料的力学性能测试。为预先了解试件力学特性,基于ANSYS和OpenSees两种软件建立了未加固短柱和加固短柱的数值有限元模型,分别进行了单调荷载、拟静力荷载和地震荷载作用下的非线性数值模拟。计算结果表明:FRP加固的主要作用在于提高延性,而对承载力提高幅度较小。4.利用上述设计的短柱试件进行了未加固短柱和加固短柱的抗震拟静力试验,试验结果表明:FRP加固钢筋混凝土短柱在小测移范围内基本不改变刚度,更主要的作用是提高构件的延性,使剪切破坏向弯曲破坏转化。研究多跨桥混合试验中的数值积分算法及加载控制方法:研究ACD-Newmark组合算法和一种限值保护下外位移加载控制方法,进一步实现了连续斜坡逼近加载技术。以一个多跨桥模型结构为例,试验单元为CFRP加固短柱模型,在实验室局域网范围内进行了弹性阶段、塑性局部破坏以及局部破坏后二次加载三种工况下的验证试验,试验结果表明:合适的误差限及延迟时间是确保加载精度和缩短试验时间的有效手段;在产生塑性变形、局部破坏之后,在一定位移范围内,试件具有稳定的二阶退化刚度,刚度值约降为未破坏时的1/3,与拟静力试验结果一致,试验结果为后续互联网协同混合试验中数值单元的设置提供参考。5.为适应目前的单自由度网络协同混合试验系统,设计了针对多跨桥抗震试验相应的两种简化方案,并进行了NetSLab软件的网络环境测试。测试结果表明:网络通讯时间占整个试验时间比例很小,目前的国内及国际网络基本能够满足混合试验要求。依据Santa Monica原型桥梁的简化模型,三校协作基于国内网络进行了四跨三柱桥梁在小震、中震和大震作用下的混合试验;依据Russion River原型桥梁的简化模型,四校协作基于国际网络进行了六跨五柱桥梁在小震、中震和大震作用下的混合试验;针对网络环境和试验时间分配的分析结果表明:大部分试验时间花费在逼近加载及等待作动器响应平稳这两项上,目前的网络环境基本能够适合慢速网络混合试验的要求。6.本文进行的两个多跨桥的混合试验是国内首次多站点网络协同示范性试验,并可以作为标准试验平台进行扩展。试验结果表明:网络协同混合试验方法实现了设备共享,为大型复杂桥梁结构抗震试验提供了一种可行的研究途径。更多还原

【Abstract】 Hybrid testing is an advanced testing method originated from substructure pseudo-dynamic testing, which integrates physical testing and numerical simulation. It can carry out a precise analysis similar to FEM, and can establish a strong functional networked collaborative hybrid testing method based on internet. This method is the hot topic in international academic circles of civil engineering, and several research institutions at home and abroad have carried out basic research.Based on the experimental resources and numerical resources of the present laboratories, the basic theory of hybrid testing method and it’s applications in RC multi-span bridge are researched, the main research contents are described as following:1. Comparied with traditional subsructure pseudo-dynamic testing method, the greatest advantage of hybrid testing is that several nonlinear experimental elements are integrated, which can carry out integral analysis not component analysis. Several distributed laboratories are connected and carried out the large-scall even full-scall test cooperatively based on internet, then the more complex tests can be carried out collaboratively.2. Aiming at MTS structural testing system used in civil engineering widely, based on the hardware of FlexTest GT control box and software of MTS 793, an internal command control method for hybrid testing is put forward. VB_COM program is used to control the input and output, and then the control of GT is implemented. Three programs that named Monitor Station program, SinCycle Test program and RampControl Test program are developed respectively. The RampControl Test program is embed in NetSLab-Tester, and the connection between MTS and NetSLab is established based on a master-slaver network. A verification test with a cantilever steel column is carried out, and the testing results show that the connection is simplified and the speed is improved. The internal command control provides a new method for hybrid testing, but needs high requirement of hardware and software, and the system PC can be protected effectively by master-slaver network.3. Aiming at a column experimental element in hybrid testing of multi-span bridge, four reinforced concrete short columns are designed, and FRP strengthening calculation based on M. J. N. Priestley shear bearing capacity model are carried out. The mechanical properties testing of different materials are tested. The finite element simulation of unstrengthening and strengthening short column based on ANSYS and OpenSees are researched and nonlinear analysis of monotonic loading, quasi-static loading and seismic loading are carried out for investigating the specimens’s mechanical properties beforehand. The numerical results show that the main effect of FRP strengthening is improving ductility not bearing capacity.4. The seismic quasi-static testing of unstrengthening and strengthening short columns are carried out respectively. The testing results show that the stiffness of FRP strengthening short columns has little improvement under small displacement. The primary function of FRP strengthening is increasing ductility and making the failure from shearing mode to bending mode.The numerical integral algorithms and loading control methods of hybrid testing are researched. An accumulated central difference method and Newmark combined algorithms, an external displacement loading control method under limit value protecting are researched, and a continuous ramp approach loading technique is implemented. Take a mulati-span bridge model structure for example, a CFRP strengthening short column is setted an experimental element, a verified hybrid testing is carried out at the stage of elastic behavior, plastic partial damage and post partial damage. The results show that a suitable diaplacemnet limit value and delay time are the effective means for satisfing the loading precision and decreasing the time. The specimen has stable 2nd order degradation stiffness at the range of some displacement, and the stiffness falls to be 1/3 of the initial value, which has consistence with the results from quasi-static testing. This work further provides a reference for settting of numerical elements in networked collaborative hybrid testing.5. In order to adapt the SDOF networked hybrid testing system, two simplified seismic testing scheme of multi-span bridge are designed. The networked environment test of NetSlab is carried out, the test results show that the proportion of communication time in the total testing time was very small, and the hybrid testing demand could be satisfied basically. Based on the simplified model of Santa Monica prototype bridge, associating with three universities, the hybrid testing of four spans three columns bridge structure in the action of small earthquake, medium earthquake and large earthquake is carried out based on domestic networked. Based on the simplified model of Russion River prototype bridge, associating with four universities, the hybrid testing of six spans five columns bridge structure in the action of small earthquake, medium earthquake, large earthquake is carried out based on international network. The networked environment and elapsed time are analyzed in detail, corresponding improvement measures are proposed. The analysis results show that the most testing time is spended on approach loading and waitting for stability of actuator, and the slow hybrid testing demand could be satisfied basically by the present network environment.6. The above two multi-span bridge hybrid testing are the first demonstrative multiple sites collaborative testing domestic, which can be extended as a standardization test platform. The testing results show that the networked collaborative hybrid testing method realizes the equipment sharing and provides a reference for seismic testing of complex bridge structure.更多还原