Damage Identification Based On Model Updating And Time Series Analysis

With the rapid development of world economy and technology, modern structural design presents a large-scale, complex, diversification trend, and also have a longer life period, influential, once it is crashed, will lead to serious life and property losses. Therefore, in order to ensure the structure of the security, integrity, applicability and durability, many new large-scale structures and infrastructures installed long-term structural health monitoring system, real-time monitoring of the security situation of the structure, it proved valuable data for the study of the structural state assessment. Although the extensive research and application in the past20years, the further research are need for the structural damage identification. Therefore, model updating and time series was brought into the structural damage identification and follow results are obtained:(1) The fundamental principle of the novelty intelligent algorithm-Harmony Search Algorithm (HSA) and improved methods were introduced. As the improved HSA has a shortcoming of easily plunging into a local optimal solution and convergent slowly when searching in an extensive range. A Fast Harmony Search Algorithm (FHSA) was put forward. This method not only ensures the intensification of the optimal solution and also increases the diversification. Finally, the suggestions of the feasibility of the FHSA was gived;(2) Harmony Search Algorithm (HSA), as a novel heuristic intelligent optimization algorithm, have been applied in many fields, but rarely seen in the field of structural health monitoring. HSA was introduced into the field of structural health monitoring, and successfully applied into structure finite element model updating. In this paper, structural finite element model updating is converted into a nonlinear optimization problem and solved by the HSA. Structural modal parameters were considered as the certainty and uncertainty respectively. Numerical simulation shows that it is difficult to choose which distribution can be used in FHSA, therefore, Improved Fast harmony search algorithm (IFHSA) was proposed. The feasibility of the HSA in the field of the finite element updating was verified and it was applied into the reduced model updating of the Canton Tower. This not only extends the applying field of HSA, but also proved a new concepts for model updating;(3) HSA has been successfully applied to the felid of structural damage identification. When structural damage was identified using the model updating method, it can be converted into an optimization problem. In this study, objective function can be established using frequency error, modal assurance criterion and residual force vector combined with different weight value, structural damage were identified by using updating the structural parameter model. The feasibility of the application of HSA in the damage identification was verified and the influence of the noise was studied. The results show that this method has certain noise immunity.(4) As an information coalescer, time series can be used to establish structural parameter model, therefore, a new damage identification method was proposed based on the time series prediction model. Firstly the structure response data preprocessing, the structural response under health were used as the reference data, reference autoregressive (AR) prediction mode was established; Second, the residual of the test structure using reference AR model, the variance of the residual were taken as the damage index., the structural damage were identified. Finally, a numerical simulation shows that the damage index can not only determine whether the structure damage occurs, but also can identify structural damage location;(5) Based on the concept that transfer function can reflect the relationship between input and output structure, a damage location method was put forward by using the ARX modal establishing the Pseudo Transfer Function (PTF), and the method was improved by combining the natural excitation technique, and make its feasible in the damage identification of structures under ambient vibration. The effectiveless of this mothod verified through the numerical simulation and6floors shear frame model experimental. Finally, this method was applied into damage identification of reduced model of Canton Tower model and, the application of this method in damage identification of high-rise structure was studied.