船舶等の衝突強度に関する研究

概要

論文の詳細を見る
The present paper describes the strength of ships and other structures against collision. Four specific problems have been considered in this paper. The investigations on collision problems were motivated by the necessity to develop reliable protection systems for nuclear powered ships. Thus, the present study examines first the energy absorption capability of such protective ship-side structures through a series of model tests. It is demonstrated that there are two fundamental types of failure in transversely framed side structures, which are discriminated primarily by the amount of external load supported by membrane tension prior to the rupture of side shell. The characteristic modes of energy absorption pertaining to these failures are revealed. Some considerations on typical protective structure arrangements are made from the viewpoint of the energy-absorption schemes. Then the investigation is performed into the crashworthiness of liquified natural gas (L.N.G.) tankers and offshore storage tanks. The energy-absorption capabilities of fundamental grillage type of double-hull models are studied, which are relevant to the protection of those cargo tanks against ship collision. The structure models are composed of an outer hull plating and an inner hull connected by flat horizontal and vertical girders welded to form cubical cellular spaces. The energy absorption efficiency, which is defined by the amount of absorbed energy per unit volume of structure members, is discussed. The deformation modes of spherical shell segments representing L.N.G. cargo tanks are also examined.The investigation thereon is concerned about a reasonable estimation of the maximum permissible limit of bow penetration into the tank. In an effort to generate information on the design of buffers for the collision protection of both ship hulls and bridge piers, an experimental investigation has been made into small idealized ship side and bow models which collide with a rigid bridge pier. The collision force and the hull deformation ave graphically presented for a range of gross tonnage of coast-going ships. Subsequently, studies on the energy-absorption schemes of several types of buffers for protection of bridge piers are carried out through the experiments. The tests reveal that the composite structures of steel shells which rigid polyurethane foam is filled in is a useful candidate for buffer equipments. Design procedures are presented by referring to the buffer equipments tentatively installed for a long span bridge. The fourth collision problem is relevant to ship collisions with offshore platforms. Two specific fields are discussed in this paper. The first concerns the local energy absorption of steel tubular members of offshore structures, which is related to the residual strength in damaged conditions. For this purpose, a series of tests on tubular members is conducted and a semi-experimental equation is developed to evaluate the local energy absorption capabilities. The amount of energy is compared with the impact energy specified by DnV rule for mobile offshore units. The second field concerns the strength of cantilever stiffened cylindrical shells subjected to a transverse load at the free end. This is associated with the collision strength of footing-type of buoyancy elements which will be presumably used for large-scale offshore platforms. It is demonstrated that DnV code makes a reasonable estimate of the collapse strength.
独立行政法人海上技術安全研究所の論文
1988-01-30

船舶等の衝突強度に関する研究

スポンサーリンク

概要

著者

関連論文

スポンサーリンク