抄録
This study is related with an approach for the diagnosis of defects or peculiar on structures using hammering test that is one of the non-destruction inspection methods of the structure. In this paper, the detection method of the defects as a non-destruction inspection method has been suggested and the efficiency of the diagnosis method based on the hammering sounds has been estimated in a simple structure model, an aluminum bar with free end. According to the simulation by FEM model, it became obvious that the natural frequencies for the relating vibration mode of the aluminum bar decrease when the crack is at the abdomen of the vibration mode. On the contrary, the natural frequencies may not be changed or the change may be small when the crack is at near the nodes of natural vibration mode. The diagnosis of the existence of the defect was done from the correlation of the Wavelet coefficient between the two sound signals from aluminum bar without and with crack. The rough position of the crack is estimated from the relationship among the natural frequencies.
