Fundamental Study on the Optimization Method for Vibration Level : Optimization for Vibration Level Corresponding to the Guidelines for the Overall Evaluation in Merchant Ship (ISO6954)

Abstract

ISO6954 (Guidelines for the overall evaluation of vibration in merchant ship), which was adopted by ISO (International Standard Organization) in 1984, is generally used as the guideline for evaluation of vibration in a superstructure. It is necessary to design the superstructure, as the vibration that occurs to the superstructure should be satisfied with the evaluation curve of this guideline. In this paper, the word of 'Linear Grade' is defined as amounts of vibration level corresponding to the ISO6954. Then the linear grade and the linear grade's sensitivity of design variables are formulated by using sensitivity analysis at the peak frequency. Furthermore, by combining the linear grade and the linear grade's sensitivity with the optimization system of vibration level, it is verified that optimization of the vibration level corresponding to the ISO6954 is possible.