Structural Damage Detection Using Virtual Passive Controllers

This paper presents novel approaches for structural damage detection which uses the virtual passive controllers attached to structures. The passive control system which mimics the mass-spring-dashpot is an energy dissipation device augmenting the system damping and thus guarantees the closed-loop system stability. Two damage detection techniques are developed. One technique uses a direct output feedback controller whereas the other technique uses the second-order dynamic feedback controller. The change in the identified natural frequencies, which are generally much less sensitive to noise and environmental uncertainties than the identified mode shapes, are used for damage detection. A least-squares technique, which is based on the sensitivity of the natural frequencies to the damage variables, is used for accurately identifying the damage variables.