Internal loss factors of ship structures and its application for computing vibration and noise

Results of internal loss factors (ILF) measurements for different ship structures are presented. It is found that dispersion of ILF is quite large. Origin of dispersion is mainly random. Statistical properties of ILF as random value are evaluated on the basis of measurement results. Computational example for vibration propagation on ship-like structure is presented. At that Statistical Energy Analysis (SEA) and probabilistic approach are used. ILF, which are generated on the basis of statistical properties, are used as input data. Calculated results show possible dispersion of vibration of distant ship structures up to 7-10 dB. Appropriateness of probabilistic approach and approximate techniques for computing of vibration and noise on ships are justified.