Analysis Of Dynamic Structural Health Diagnosis Based On Transfer Function

Numerous in-service structures has entered the aging state, and many of the structures are in sick at work in our country nowadays. Health diagnosis and monitoring have become an indispensable methods to both of the completed buildings and the under constructed buildings. It is an urgent and very meaningful research to carry out fast and accurate health diagnosis and monitoring methods for the building structure. Dynamic structural health diagnosis, which based on the current transfer function, is a commonly used detection method. A five-story frame structure and a gravity dam were studied respectively as case study in this paper. In order to provide a theoretical basis and practical models for the dynamic structural health diagnosis which based on the transfer function, finite element software(Ansys) was used to calculate the seismic response of structures in the different damage cases, the law of seismic displacement and acceleration response of structures were studied, which variation with stiffness degradation and quality reduced of the vulnerable parts of the structure. Matlab mathematical toolbox were use to fit transfer function expression, and the difference of transfer function expression of structure system were analyzed in different conditions. The law of transfer function variation with structural location and extent of damage were revealed.The key summarized studies are as follows:1) The current status and development trend of structural damage detection method were reviewed, and the applicability of the method commonly used in dynamic testing of structures abroad were comparative analyzed. The necessity and urgency of the dynamic testing for in-service structure which based on the transfer function were also present.2) Taking a five-story frame structure and a gravity dam as case study, the law of seismic displacement and acceleration response of structures were studied in the case of EL-Centro seismic wave excitation, by using ANSYS. The response of change variation of the peak displacement and the peak acceleration of the structure varied with the stiffness degradation and quality reduced of the vulnerable parts of the structure. The law of seismic displacement and acceleration response to the stiffness and quality of structures were studied,3) The transfer function expression in the form of ARMA were fitted by using Matlab mathematical toolbox, and the law of transfer function variation with the stiffness and quality of structural location and extent of damage were present.