안티롤링 진자에 의한 선박의 횡동요 저감에 대한 연구

Abstract

As ships and marine structures float on the water surface, they are usually exposed to waves, and move unceasingly. Rolling motion of floating body makes crews and passengers exhausted and/or applies forces to the structure to cause damage, and even might upset the body. Therefore bilge keels are equipped in almost ships for anti-rolling, in special case anti-rolling tank(ART) or fin stabilizer or gyroscope could be installed. But ART requires big capacity to install, and fin stabilizer and gyroscope need much costs to install and also much expenses to operate and maintain.

Recently the new Anti-Rolling System(ARS) which has a moving mass on the arc rail with passive control system was introduced, and showed abilities to suppress ship’s rolling. And this device was also very big, heavy and expensive.

This paper suggests the Anti-Rolling Pendulum(ARP) which moves on the circle shaped orbital track, induces the linear equation of motion and nonlinear equation of motion, and confirms the effectivities by comparing with the experiments.

The conclusions are as follows;

1. A linear equation and a non-linear equation of the roll motion of ship with the ARP is suggested, and the application of ARP system shows the effectiveness by comparing with the experimental result.

2. The ARP’s remarkable damping ability is proved by experiments and analysis. The 32g ARP has the same or better damping performance comparing with the 50cc ART.

3. The ARP with cylinder type could reduce the device volume remarkably comparing with the ART.

4. Not so big additional space needed for installing ARP by placing it on the front wall of the engine room or in the cofferdam.

As the weight of about 0.5% of ship’s displacement is so heavy for a big ship, the ARP for a big ship might be needed more additional studies. But for fishing boats or small passenger boats the proposed ARP would be powerful to reduce the roll motion of boats.