부산대학교 도서관

Dynamic characteristics of a structure have been using as an input data in the area of structural health monitoring. Since natural frequencies can be measured easily and less affected by experimental errors, in most of the studies have resorted to the changes in natural frequencies. But if the system is symmetrical, damages in different locations make identical changes in a pair of natural frequencies. The modal data which the paper dealing with are natural and anti-resonant frequencies associated to solve this problem in a symmetrical systems. This paper deals with identification of open cracks in a vibrating beam under bending vibration. The detection method is based of the genetic algorithm(GA). First, natural and anti-resonant frequencies were extracted by finite element cantilever models which have open cracks. These modal data were used as input data of detection program based the GA. Second, modal data were measured using experimental modal analysis which used in model updating between theoretical and real damaged beam structures. Finally, severity and locations of damages in a beam structure are detected by GA.