On the use of the autocorrelation function to identify the damage in the side shell of a ship's hull

When structural damage occurs, the dynamic characteristics of the structure changes correspondingly. This can be used to detect damage occurrence. In this paper, an autocorrelation function was utilized to identify damage in the side shell of ship structures using a combination of experimental and numerical studies. A stiffened plate was used to model the side shell of a ship structure. The damage was simulated by a cut in the longitudinal near the transverse member. The cut was made using a hacksaw. An experimental study using modal testing methods was carried out to measure the random response time history of the undamaged and damaged stiffened plate model. The random response time history was used to obtain its autocorrelation function and its random decrement signature. The autocorrelation function was then compared with the random decrement signature. Finite element models were developed for the stiffened plate, in the undamaged and damaged conditions. The random responses of the model were used to obtain the autocorrelation functions. The autocorrelation functions obtained numerically were compared to the ones obtained experimentally. The results indicate that the autocorrelation functions can be used to identify the occurrence of damage in the stiffened plate model.