PROGRESS OF DAMAGE DETECTION FOR STRUCTURAL HEALTH MONITORING

This paper discusses the current approaches of structural damage detection in structural health monitoring (SHM) and their respective features. The damage detection methods are classified into two cate- gories, one is based on the theory of modal analysis and another is based on signal processing of the structural dynamic tests. The damage detection method in the first category uses low order vibration modes of the structure and requires dynamic testing on the whole structure, the dynamic responses of the structure can be calculated from its finite element model. In the second category, the damage detection method is usually used to detect damage of structural components by the damage characteristic parameters extracted from measured dynamic response data without finite element modeling of the structure. The concepts of comparative method and non-comparative method of damage detection are proposed in this paper. In the comparative damage detection method, the characteristic parameter of the intact structure is required to serve as the comparing template, while the non-comparative method determines the damage state directly from the measured dynamic response of the structure with the help of some physical and engineering knowledge. The problems of signal sensing and processing techniques and the collocation of sensors used in damage detection are also discussed in this paper. The approach to quantify damage severity and to estimate residual life of the damaged structure by combined active and passive detecting techniques is proposed.