Abstract
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 cantilevered beam. Simulations by FEM model made it obvious that the natural frequencies for the relating vibration mode of the aluminum beam decrease when the crack is at the anti-node 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. Detecting the existence of the defect was carried out by RMS of Wavelet coefficients between two hammering sound signals measured from aluminum beams without and with crack. Rough position of crack could be estimated from the relationship among the natural frequencies.
