ABSTRACT
Damage detection methods can be classified into two major categories depending on the nature of the experimental data: dynamic identification methods that use dynamic test data and static identification methods that use static test data. Compared with the static identification techniques, the dynamic methods have been more fully developed (Doebling et al., 1998b). To obtain a good estimation of the damage parameters, many difficulties inherent in the dynamic identification methods have to be overcome, such as the damping and mass changes due to the damage and the accurate measurements of higher vibration modes and frequencies. These may be very difficult with the experimental data analysis. However, the static identification method is usually simpler, since the static equilibrium equation only involves the stiffness properties of a structure. Also, static testing is comparatively cheaper and many advanced techniques have been developed recently for the static measurement. Accurate deformation or strain of the structure can be obtained rapidly and economically. Therefore, this group of methods attracts much attention from the engineering industry. This chapter gives a brief description of this group of methods. Basically, the static
parameter estimation is based on measured deformations induced by static loads, such as a truck on a bridge deck, a mass on a building or an actuator-induced static load on a structure. Section 5.2 gives the output error functions for system identification. Section 5.3 describes several techniques to detect the local damage based on static deflection profiles. Finally, the limitations of these methods are discussed in Section 5.4.
