The problem of identification of the modal properties of a structural system has received much attention over the years because of its importance in structural model updating, structural health monitoring and structural control. This paper presents dynamic properties such as natural frequencies and mode shapes of a scaled model of floating structure. A modal testing is performed on the structure and modal parameters for the structure are extracted from the measured data. The results are compared to a finite element model of the floating structure and the correlation between the measured and analytical modal parameters is investigated.
Dynamic characteristics of a structural system, such as natural frequency, damping, and mode shape have been widely used for structural model updating, structural health monitoring, and structural control by many researchers. In the early period of structural health monitoring, studies have focused on the possibility of using modal properties such as shifts in resonant frequencies as indicators of structural damage. Many researchers have investigated and applied vibration monitoring to offshore structures (Vandiver, 1977; Kenley and Dodds, 1980; Osegueda et al., 1992). The consequence of seismic events and failure of bridge have resulted in attempts to monitor the integrity of bridges (Biswas et al., 1990; Choi et al., 2004). The use of sensitivity approaches based on the relationship between the eigenfrequencies, modal stiffness, modal mass, and modal damping have focused on the development of methods that predict the location and magnitude of any damage in the structure (Stubbs and Osegueda, 1990). In addition, Park et al. (2006) presented blind test results of damage detection by using the simulated time domain data from a four-story steel frame. They reported the results of modal analysis and also reported damage locations and estimation of damage severities for two damage cases using only mode shapes of undamaged and damaged structures
