Ship vibration analysis

Abstract

Ship vibration phenomena have been noticed since the first days of internal propulsive power. At first typical vibration levels were such so as not to be more than a mere annoyance, and were generally taken to be an unavoidable price which had to be paid for the comfort of internal propulsion. With the advent of more powerful engines, larger ships and an increase in the standards of passenger ships, ship vibration became a problem which had to be solved. The increasing sophistication of warships also necessitated the provision of acceptable vibration levels and since in most cases a vibration-prone ship is not a good warship most of the early research was carried out for some of the world's navies. There are basically two types of vibration classes and three ways in which to solve them. In the first type, the whole hull vibrates along its length very much like a vibrating beam. This type of vibration is at its worst when the generator of such vibrations, such as the main engines, is operated at a speed corresponding to the fundamental frequency of the ship's hull.