基于环境振动的设缝相邻结构模态参数识别及有限元模型修正

发布时间：2018-06-01 20:12

本文选题：变形缝 + 相邻结构　；参考：《北京交通大学》2017年硕士论文

【摘要】：对于设缝相邻结构,在设计阶段通常假定彼此是相互独立的。结构建成后,变形缝的处理措施可能引起相邻结构的相互作用,进而改变独立结构的动力特性。因此,本文利用环境振动测试,并考虑测试误差和模型误差的不确定性,利用概率方法对设缝相邻结构的模态参数进行识别,分析变形缝对相邻结构动力特性的影响,并提出设缝相邻结构的有限元建模方法。为了考虑模型参数设计值与实际值的区别及测试误差和模型误差的不确定性,得到更为精确的有限元模型,利用概率方法和识别结果对所建立的有限元模型进行修正。本文的主要研究内容及结论如下:(1)分别对三栋多层设缝钢筋混凝土相邻结构进行了环境振动测试,利用实测加速度数据和快速贝叶斯FFT方法对结构进行了模态参数识别,得到了相邻结构的自振频率、阻尼比、振型的最有可能值及定量表征其不确定性的变异系数。识别结果表明:楼板装修面层如地砖在伸缩缝处未断开,则相邻结构的动力特性完全相同,即通过变形缝处的连接成为一个整体,结构间为强相互作用;伸缩缝内有刚性填充物,则相邻结构的扭转模态会比沿长轴方向的平动模态提前出现,结构间为中等相互作用;防震缝按照设计来施工,则由于相邻结构间的相互作用产生的模态会出现在较低或等高的结构中,结构间为弱相互作用。(2)定量考虑模型误差及测试误差的不确定性,提出了一种基于贝叶斯理论和应用程序交互访问的有限元模型修正方法,实现了对精细化有限元模型物理参数的直接修正,通过数值算例验证了该方法的可行性,对比分析了两种不同贝叶斯目标函数的修正效果。(3)提出了设缝相邻结构的有限元建模方法:利用跨越伸缩缝的板模拟结构间的强相互作用,利用在伸缩缝处增加长轴向刚度模拟结构间的中等相互作用,对于结构间的弱相互作用采用相互独立的模型,三栋设缝相邻结构的有限元模态分析结果与识别结果基本一致。同时,利用前文所提方法和识别结果,对所测相邻结构的有限元模型进行了修正,取得了较好的修正效果。
[Abstract]:For seams adjacent structures, it is usually assumed that they are independent of each other at the design stage. After the construction of the structure, the treatment measures of the deformation joint may cause the interaction of adjacent structures, and then change the dynamic characteristics of the independent structure. Therefore, in this paper, the modal parameters of adjacent structures with joints are identified by using the probabilistic method, and the influence of deformation joints on the dynamic characteristics of adjacent structures is analyzed by using the environmental vibration test and considering the uncertainty of test error and model error. A finite element modeling method for adjacent structures with joints is proposed. In order to consider the difference between the design value and the actual value of the model parameters and the uncertainty between the test error and the model error, a more accurate finite element model is obtained, and the established finite element model is modified by the probability method and the recognition result. The main contents and conclusions of this paper are as follows: (1) the environmental vibration of three adjacent multi-story reinforced concrete structures is measured, and the modal parameters are identified by using the measured acceleration data and the fast Bayesian FFT method. The most probable values of the natural frequency, damping ratio, mode shape of adjacent structures and the coefficient of variation that quantitatively characterize the uncertainty of the adjacent structures are obtained. The identification results show that the dynamic characteristics of adjacent structures are identical if floor tiles are not disconnected at the expansion joints, that is, the joints are connected into a whole and the structures are strongly interacted. If there is a rigid filler in the expansion joint, the torsional mode of the adjacent structure will appear earlier than the translational mode along the long axis, and the interaction between the structures will be moderate. Then the modes produced by the interaction between adjacent structures will appear in the structure of lower or equal height, and the uncertainty of the model error and the test error will be taken into account in the quantitative consideration of the uncertainty of the model error and the test error. A finite element model modification method based on Bayesian theory and interactive access of application programs is proposed. The physical parameters of the refined finite element model are directly modified. The feasibility of the method is verified by numerical examples. A finite element modeling method for adjacent structures with joints is proposed. The finite element modeling method is used to simulate the strong interaction between structures by means of plates spanning expansion joints. The intermediate interaction between the structures is simulated by adding long axial stiffness to the expansion joints, and the weak interaction between the structures is modeled by an independent model. The results of the finite element modal analysis of the three jointed adjacent structures are in good agreement with the identification results. At the same time, the finite element model of the adjacent structures is modified by using the method and the recognition results, and a better effect is obtained.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU311.3

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