基于嵌入式阻抗模型和小波谱单元的混凝土结构损伤诊断

A study on damage diagnosis of concrete structures based on an embedded impedance model and wavelet spectral element will be performed in order to reflect the veritable changes in physical performances and mechanical responses of concrete structures and to detect incipient damage inside concrete structures. The embedded impedance model is established based on the existing impedance models, which can truly reflect the 3D and multi-direction force interaction between piezoelectric impedance transducer and concrete structure. The concrete structure containing piezoelectric impedance transducers is numerically modeled and analyzed by finite element method, and the analysis results will be compared to those based on the embedded impedance model. An experimental study on health monitoring and damage detection for concrete structures is implemented to localize damage and demonstrate the correctness of the above-mentioned finite element model and embedded impedance model. Subsequently, the methodology of wavelet spectral element will be studied, and the damaged and undamaged concrete structures will also be simulated and quantitatively analyzed by wavelet spectral element method. Combined with the measured piezoelectric impedance signals and the improved genetic algorithm, the established wavelet spectral element model is updated and the size of incipient damage of concrete structure is identified quantitatively.

为了真实反映混凝土结构内部物理性能和力学响应的变化，检测混凝土结构内部微小损伤，本项目将开展基于嵌入式阻抗模型和小波谱单元的混凝土结构损伤诊断研究。项目将在已有阻抗模型的基础上建立能准确反映埋入式压电阻抗传感器与混凝土结构之间三维、多向力相互作用的嵌入式阻抗模型；利用有限元法对压电混凝土结构进行数值建模和分析，将数值分析结果与嵌入式阻抗理论模型分析结果进行对比研究，并通过试验验证已推导的嵌入式阻抗理论模型和有限元数值模型的正确性；对混凝土结构进行分布式健康监测和损伤检测试验研究，实现混凝土结构的损伤识别和定位；开展小波谱单元法理论与算法研究；利用小波谱单元法对损伤前后的混凝土结构进行数值建模和损伤定量分析，同时借助压电阻抗测试信号以及改进的遗传算法对已建模型进行修正，定量地识别出混凝土结构初始损伤的大小。

为了真实反映混凝土结构内部物理性能和力学响应的变化，检测混凝土结构内部微小损伤，本项目开展了基于嵌入式阻抗模型和谱单元的混凝土结构损伤诊断研究。项目在已有阻抗模型的基础上建立了能准确反映埋入式压电阻抗传感器与混凝土结构之间三维多向力相互作用的嵌入式阻抗模型；利用有限元法对压电混凝土梁结构进行了数值建模与分析，将数值分析结果与嵌入式阻抗理论模型分析结果进行了对比研究，并通过试验验证了已推导的嵌入式阻抗理论模型和有限元数值模型的正确性；对混凝土梁、板结构进行了分布式健康监测和损伤检测试验研究，实现了混凝土结构的损伤识别和定位；开展了基于拉普拉斯变换及小波变换的谱单元法理论与算法研究；利用谱单元法对损伤前后的混凝土梁结构进行了数值建模和损伤定量分析，同时借助压电阻抗测试信号以及改进的遗传算法对已建模型进行修正，定量地识别了混凝土梁结构初始损伤的大小。此外，本项目还提出了应变统计矩这一新的损伤识别指标并建立了基于应变统计矩差的梁类结构损伤检测两步法，数值与试验研究结果证实了该方法的有效性。