NUMERICAL AND EXPERIMENTAL CONSIDERATION OF FREQUENCY DOMAIN DECOMPOSITION METHOD FOR MODAL PARAMETERS IDENTIFICATION OF STRUCTURE

Classical modal testing of large structures such as bridges, towers and building is encountered with some problems such as exciting the structure and noisy environment. Therefore, researchers have proposed some new methods for identification of dynamic properties by measuring only the responses of structure. In this paper, one of the well-known methods entitled Frequency Domain Decomposition (FDD) is considered numerically and experimentally. The finite element method was used to conduct a model of a six stories building. The model was excited by random forces in a simulated test and modal parameters of the building were estimated. Also, the sensitivity of the results to the location and the type of excitation and measurement noise has been evaluated. To consider the FDD method experimentally, a clamped-clamped beam has been used. The classical and operational modal tests have been conducted on the beam and the modal parameters were estimated. The results of numerical and experimental studies show the effectiveness and accuracy of the FDD method in identification of modal parameters of structure.