Based On The Fractal Theory Of Bridge Structure State Analysis

Research on Bridge Structure Health Monitoring and state analysis Technology, Based on the dynamic response of the bridge structure theory and time series analysis theory and technology are paid more and more attention on the study of bridge structure monitoring technology. This paper, fractal theory are introduced, nonlinear behavior and on the basis of fractal characteristics are explored, comprehensive Hurst index and multifractal indexes of bridge system state analysis technology, combining Midas Simulation Model with real bridge scale model was validated. The main contents include:? Bridge structure nonlinear influence factors and its mechanism are explored, analyzing bridge system fractal feature in the nonlinear cases from the theory and laying the foundation for further analysis based on fractal theory of bridge structure.? For the system response of the time series fractal features prominent enough in full cycle problem, introduced the Hurst index to analyze the of long-range correlation analysis of structural vibration acceleration time sequence, finding the fractal characteristics of the vanishing point, thereby obtaining the time series fragment which own fractal characteristics.? For the single fractal characteristics of indicators characterizing the system state lack completeness, putting forward the multifractal characteristic index system which is made of the weight factor, the quality index, singular index and multifractal spectrum by using multifractal theory to analyze the structural vibration acceleration time series of long-range correlation time sequence fragment, thus building the comprehensive Hurst index and multifractal indicators of the structure system state evolution mode.? Depending on the Midas simulation model and real bridge scale model, first, through the Hurst index structure in the different conditions extract acceleration time series own obvious fractal characteristics of time sequence fragment,then, the time series fragment using multifractal theory, analysis of natural frequency and intensity of the inherent parameters of structure state and the correlation of multifractal parameters. The results show that "the length of the memory" of vibration acceleration time series of bridge structure system own obvious differences, existing long-range correlation in the normal conditions, and multi-fractal spectrum evolution of the system state bridge structure sensitive.