Frequency-Domain Hybrid GA and Recursive Hybrid GA to Structural Dynamic Parameter Identification

• Main Authors: Yong-Cin Tsai, 蔡永勤
• Other Authors: Grace S. Wang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/44496740904856579706

碩士 === 朝陽科技大學 === 營建工程系碩士班 === 99 === Currently, in various important buildings, schools, bridges and other civil buildings in Taiwan are equipped with Strong-motion seismographs. It can recording the relevant information when the earthquake occurred. We can use those data to identify the system parameters of structure and building’s damage assessment. And the structural reinforcement is also according to the assessment result. Over the past few decades there are already developed many system identification methods that can be applied to buildings system identification and quickly to understand the post-earthquake system characteristics. In recent years, many scholars use the results of system identification to do the structural health monitoring research. Structural health monitoring is comparative the structure parameters or baseline state before and after earthquake to determine the location and extent of damage due to earthquake. The time-domain hybrid genetic algorithm has to take more time to count the response. In order to accelerate the identification process, hybrid GA in the frequency domain is developed. That is using Fourier transform to convert the response, because frequency-domain operations only need to use algebraic approach, compared to time-domain differential approach to computing is more rapid, it can significantly reduce the computation time. This will be applied in the numerical simulation of the dynamic characteristics of the system to identify, verify its feasibility; used in order to be more realistic to determine the feasibility of the building, but also for the numerical simulation of the earthquake with the noise and response records to identify new identification method to study identification. Finally, the method is applied to real building - Taiwan Electricity Main Building. The comparison is made between the results in the frequency domain and the time domain. Either time-domain or frequency-domain hybrid genetic algorithm, nonlinear systems are not used. In order to implement the hybrid GA to nonlinear system, the time history of the measurement is divided into a series of time intervals. Then, the model of equivalent linear system is employed to identify the modal parameters of the system for each time interval. this research and then propose a recursive application of hybrid genetic algorithm to nonlinear system identification, recursive hybrid genetic algorithms method is used to identify sub-way, the recognition results can be seen when the building affected by the earthquake when the parameters change. Verification of this law is similar to the frequency-domain hybrid genetic algorithm approach is the use of numerical simulation system and containing the numerical simulation of seismic noise records and the reaction verify its feasibility. Finally, recursive hybrid genetic algorithm applied to real building - National Center for Research on Earthquake Engineering, and Taitung Fire Brigade building, and algorithm is applied to these structures and the damage indices are then computed according to the identified parameters. By monitoring the variation of the identified parameters, the damage assessment of these structures is performed and the damage states of these structures are evaluated.