Development of a damage detection system for structures using strain memorizing sensors

在对系统辨识方法进行综述的基础上，提出了几种与系统辨识相对应的方法，如自适应H_无穷和卡尔曼滤波、具有网络结构记忆能力的神经网络和自适应蒙特卡罗滤波。这些算法具有有效的时间推进能力，可以识别非线性和非平稳结构系统。为了提高结构参数非平稳变化的收敛速度，提出了一种卡尔曼滤波与蒙特卡罗滤波相结合的混合算法，并将遗传算法引入到蒙特卡罗滤波中。同时还发展了参数和非参数系统辨识技术，适用于处理高度非线性和时变的系统。这些算法在高速笔记本电脑上实现和执行，通过AD转换与来自观测系统的输入数据同步，该结构识别系统能够实时识别结构参数的非平稳变化。开发了简单、廉价的被动传感器，可以监测峰值应变或位移。通过将LC电路引入传感器启用的数据无线读取，可以无线检索存储的数据。制作了传感器样机并进行了测试，将无线数据采集系统与结构识别系统相结合，研制了一种用于结构系统识别的便携式设备。通过三层框架结构的微震观测，验证了所开发系统的有效性。

Based on a recent review of system identification, we developed several promising methodologies corresponding to the system identification such as an adaptive H infinity and Kalman filter, a neural network with forgetting capability of network structure and an adaptive Monte Carlo filter. Those algorithms possess efficient time-marching capabilities to identify non-linear and non-stationary structural systems. To improve convergence of non-stationary change of structural parameters we also developed a hybrid algorithm combining the Kalman filter with the Monte Carlo filter and the Genetic algorithm was also introduced into the Monte Cairo filter. Both parametric and non-parametric system identification technologies were also developed suitable to deal with highly nonlinear and time varying systems. Those algorithms were implemented and executed on a high speed laptop computer synchronized with input data through AD converters from an observation system, a structural identification system, which enables a real time identification of non-stationary change of structural parameters.Simple and inexpensive passive sensors that can monitor the peak strain or displacement were developed. The memorized data can be wirelessly retrieved by introducing an LC circuit into the sensor enabled wireless reading of the data. A prototype sensor was fabricated and tested.A portable equipment to be used for structural system identifications was developed by combining a wireless data acquisition system with the structural identification system. Efficiency of the developed system was demonstrated by micro-tremor observations of a three stories frame structure.