碾压混凝土结构流激振动特性及损伤识别研究
发布时间：2019-05-18 00:55
【摘要】：泄流诱发水工结构振动是一种复杂的流固相互作用现象,在复杂的泄流荷载作用下可能引起结构的剧烈振动,甚至破坏。碾压混凝土结构在泄流激励条件下结构的振动特性更加复杂,开展泄流条件下结构的振动机理及损伤识别研究,对碾压混凝土泄流结构的设计及安全运行具有重要的指导意义。本文通过开展泄流结构水弹性模型试验以及数值分析,结合泄流结构的流激振动特性,对碾压混凝土分层结构的流激振动特性进行了研究,分析了水流荷载、泄流结构自身特性以及流激振动响应三者之间的关系。对应变模态与结构损伤之间的敏感性以及应变模态的正交性进行了理论分析和总结,并汇总了现有的基于应变模态的结构损伤识别指标,主要内容如下:(1)开展了一系列泄流条件下结构振动模型试验,应用谱分析、波形分析以及时频分析等方法对试验数据进行分析。通过分析不同结构形式的导墙模型在泄流荷载激励下的振动响应特征,来研究整体及分层结构在泄流条件下的随机共振特性;(2)结合水力拍振的概念,对不同结构形式的泄流结构在不同荷载作用下开展有限元数值计算,对比分析整体与成层结构的振动响应特性,并对成层结构在泄流条件下出现的流激振动现象进行合理解释,为高碾压混凝土坝的设计、施工以及后期的运行管理提供依据;(3)对导墙结构进行数值模拟分析,得出整体和损伤结构应变模态的三维分布,分析了在不同损伤类型及损伤位置条件下导墙结构应变模态的变化特性;(4)针对裂缝及软弱带等损伤形式提出了基于应变指标的动应变时程识别方法,分别根据结构各测点动应变时程的偏态系数和均方差分布可以实现对结构损伤的准确识别;提出了光纤传感和应变指标相结合的损伤识别方法。
[Abstract]:The vibration of hydraulic structure induced by discharge is a complex phenomenon of fluid-solid interaction, which may cause severe vibration and even destruction of the structure under complex discharge load. The vibration characteristics of RCC structure under discharge excitation are more complex. The research on vibration mechanism and damage identification of RCC structure under discharge condition is of great significance for the design and safe operation of RCC discharge structure. In this paper, through the hydroelastic model test and numerical analysis of the discharge structure, combined with the flow-induced vibration characteristics of the discharge structure, the flow-induced vibration characteristics of roller compacted concrete layered structure are studied, and the flow load is analyzed. The relationship between the characteristics of discharge structure and the response of flow-induced vibration. The sensitivity between variable mode and structural damage and the orthogonality of strain mode are analyzed and summarized theoretically, and the existing structural damage identification indexes based on strain mode are summarized. The main contents are as follows: (1) A series of structural vibration model tests under discharge conditions are carried out, and the test data are analyzed by spectral analysis, waveform analysis and time-frequency analysis. By analyzing the vibration response characteristics of guide wall models with different structural forms under discharge load, the stochastic resonance characteristics of the whole and layered structures under discharge conditions are studied. (2) combined with the concept of hydraulic beat vibration, the finite element numerical calculation of different structural forms of discharge structure under different loads is carried out, and the vibration response characteristics of the whole structure and the layered structure are compared and analyzed. The phenomenon of flow-induced vibration of layered structure under discharge condition is explained reasonably, which provides the basis for the design, construction and later operation management of high roller compacted concrete dam. (3) the numerical simulation analysis of the guide wall structure is carried out, and the three-dimensional distribution of the strain mode of the whole structure and the damage structure is obtained, and the variation characteristics of the strain mode of the guide wall structure under different damage types and damage positions are analyzed. (4) aiming at the damage forms such as cracks and weak zones, a dynamic strain time history identification method based on strain index is proposed. According to the skewness coefficient and mean square error distribution of the dynamic strain time history of each measuring point of the structure, the accurate identification of structural damage can be realized. A damage identification method based on optical fiber sensing and strain index is proposed.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV33
本文编号：2479537
[Abstract]:The vibration of hydraulic structure induced by discharge is a complex phenomenon of fluid-solid interaction, which may cause severe vibration and even destruction of the structure under complex discharge load. The vibration characteristics of RCC structure under discharge excitation are more complex. The research on vibration mechanism and damage identification of RCC structure under discharge condition is of great significance for the design and safe operation of RCC discharge structure. In this paper, through the hydroelastic model test and numerical analysis of the discharge structure, combined with the flow-induced vibration characteristics of the discharge structure, the flow-induced vibration characteristics of roller compacted concrete layered structure are studied, and the flow load is analyzed. The relationship between the characteristics of discharge structure and the response of flow-induced vibration. The sensitivity between variable mode and structural damage and the orthogonality of strain mode are analyzed and summarized theoretically, and the existing structural damage identification indexes based on strain mode are summarized. The main contents are as follows: (1) A series of structural vibration model tests under discharge conditions are carried out, and the test data are analyzed by spectral analysis, waveform analysis and time-frequency analysis. By analyzing the vibration response characteristics of guide wall models with different structural forms under discharge load, the stochastic resonance characteristics of the whole and layered structures under discharge conditions are studied. (2) combined with the concept of hydraulic beat vibration, the finite element numerical calculation of different structural forms of discharge structure under different loads is carried out, and the vibration response characteristics of the whole structure and the layered structure are compared and analyzed. The phenomenon of flow-induced vibration of layered structure under discharge condition is explained reasonably, which provides the basis for the design, construction and later operation management of high roller compacted concrete dam. (3) the numerical simulation analysis of the guide wall structure is carried out, and the three-dimensional distribution of the strain mode of the whole structure and the damage structure is obtained, and the variation characteristics of the strain mode of the guide wall structure under different damage types and damage positions are analyzed. (4) aiming at the damage forms such as cracks and weak zones, a dynamic strain time history identification method based on strain index is proposed. According to the skewness coefficient and mean square error distribution of the dynamic strain time history of each measuring point of the structure, the accurate identification of structural damage can be realized. A damage identification method based on optical fiber sensing and strain index is proposed.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV33
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