Crack Identification on a Cross-Stiffened Plate Panel

Early identification of cracks in complex structures is desirable for the safety of operation and economy of maintenance of the structure. Monitoring of the vibration response of structures is a well-known technique for crack identification. As the complexity of the structure increases manual inspection becomes difficult and the use of on-line monitoring techniques for crack detection becomes more desirable. This paper discusses the use of a structure’s vibration response in the early detection of cracks. Analytical and experimental studies of the effect of cracks on the vibration response of an 1/20 scale aluminum model of the stiffened side shell panel of a tanker were carried out. The model was carefully designed to obtain natural frequencies and mode shapes similar to those of the prototype structure. The results of the analytical study were used to determine the best locations to place the sensors on the experimental model. Results of the experimental and analytical studies are reported.