Comparative natural global vibration modes analysis of two gas carrier maritime ships

This technical paper presents a comparative study of two gas carrier maritime ships, focusing on their natural global vibration characteristics. The selected ships are an LPG carrier with a length of 125.6 m and an LNG carrier with a length of 289.3 m, both of which have fully developed structural models, previously used for strength assessment analysis. For both ships, relevant loading conditions are selected, full cargo and ballast cases. The natural global vibration analysis provides the vertical, horizontal, torsional, and longitudinal eigenmodes, with or without the inclusion of the fluid-structure effect. The results emphasize the sensitivity and the differences in the two ships’ structures on the modal vibration characteristics.