STUDY ON THE DAMAGE DETECTION OF SPACE STRUCTURE SYSTEMS BY SYSTEM IDENTIFICATION APPROACH

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This study is concerned with the damage detection of space truss and frame structures by using small-scaled experimental models. These structures are composed of a large number of members. To carry out the damage detection of space structures effectively and efficiently, a system identification approach is promising. However, it is widely believed that the system identification is good for global damage detection but not so useful for local damage detection. To overcome this problem, in this study, the intermediate damage detection is incorporated between global and local damage detection. In the case of the damage detection of space trusses, the damaged region is inferred by using the change in the kinetic energy distribution before the pinpoint of damaged members. In the case of the damage detection of space frames, the damaged story is located and evaluated before the pinpoint of damaged portions within the damaged story. To enhance the accuracy and robustness of the damage detection scheme, moreover, local and higher-mode vibrations are excited in addition to global and lower-mode vibrations. In the case of space trusses, a series of impact hammer tests have been performed in order to excite local vibrations after a series of shaking table tests. In the case of space frames, a small vibration generator is installed in the experimental model in order to excite higher-mode vibrations after a series of shaking table tests. It is shown that the system identification approach is still very useful for the local damage detection of space structures by using a multi-level damage detection scheme.