ABSTRACT

To oil tanker and LNG carrier with membranetype containment system, the tank wall as an integral part of hull structure is regarded as a rigid boundary. The loads and forces from ship motion excitation are directly transferred to the rigid tank wall, which is called non-elastic support tank in this paper. As the support of the independent tank belongs to elastic structure, the ship motion excitation needs to be passed to the tank through elastic support structure so as to induce the liquid sloshing, which in turn feeds back to the elastic support structure. Accordingly, the motion of the independent tank is the combined results of elastic support passing the external excitation and inner tank liquid

1 INTRODUCTION

As the natural gas is widely used as a clean and efficient energy source around the world, the need for the transportation and storage of the gas arises, various LNG carriers and offshore floating LNG plant concepts have aroused wide concern. The International Gas Carrier (IGC) code defines membrane tanks as well as three type categories for self-supporting tanks. Instead of constituting a part of the hull, the self-supporting tanks are independent of hull structure, so they are also called the independent tanks, such as the IMO Type B tanks including SPB (Self-supporting, Prismatic IMO Type B) by IHI and Moss spherical tank by Moss Maritime.