JP2005225356A - Double hull structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double hull structure in which any stress concentration is not present in a bilge part, and deformation or damages hardly occurs. <P>SOLUTION: A double bottom is constituted of a bottom shell plate 11 and an inner bottom plate 12, and a double side is constituted of a side shell plate 13 and a double side bulkhead 14. A bilge hopper part 20 is provided between the double bottom and the double side. A bilge inner plate 22 of the bilge hopper part 20 is formed in a curved surface, and smoothly joined without forming any angle at a joining part with the inner bottom plate 12 and a joining part with the double side bulkhead 14. Thus, no stress concentration is present in the joining part of the bilge inner plate 22, deformation or damages hardly occur by the external force to the bottom, and the tank capacity is increased. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a double hull structure. More specifically, the present invention relates to the structure of the intersection between the double ship bottom and the double ship side in a ship.

  A conventional double hull structure will be described with reference to FIG. The ship bottom is formed into a double ship bottom by a ship bottom outer plate 11 and an inner bottom plate 12. The ship side is constituted on the double ship side by the ship side skin 13 and the double ship side wall 14. Between the ship bottom and the ship side, an outer bilge outer plate 51 and an inner bilge portion swash plate 52 form a bilge hopper portion. The bilge outer plate 51 is curved and connected to the ship bottom outer plate 11 and the ship side outer plate 13. The bilge swash plate 52 is a flat plate and is connected to the inner bottom plate 12 and the double ship side wall 14. In addition, 53 is a stiffener attached to the inner surface side of the bilge part swash plate 52 (refer nonpatent literature 1).

Since the bilge part swash plate 52 is a flat plate, it is joined to the inner bottom plate 12 at an angle, and is also joined to the double ship side wall 14 at an angle. Therefore, stress concentration is likely to occur at the two joint portions.
The stress concentration factor at the edge of the floorboard is given by (1 + 0.112 · d / r) (according to the shipbuilding design manual). Where d is the height of the double bottom and r is the corner radius of the joint. Therefore, if d = 1150 mm and r = 60 mm, the stress concentration coefficient of the joint portion between the bilge portion inclined plate 52 and the inner bottom plate 12 becomes a high value of 3.15.
By the way, an upward force acts on the bottom of the ship due to buoyancy and waves, so that the bottom of the ship is bent. When there is a load in the cargo hold, the weight of the load suppresses the bending, but in the case of an empty load, both the ship bottom outer plate 11 and the inner bottom plate 12 are greatly bent easily. As a result, stress concentration occurred at two connecting portions of the bilge portion swash plate 52, and there was a high possibility of causing deformation and damage.

Basic knowledge of merchant ship design, pages 124-125, published on August 18, 2001 by Ship Text Study Group, published by Naruyamado Shoten

  In view of the above circumstances, an object of the present invention is to provide a double hull structure in which stress is not concentrated on a bilge portion and deformation and damage are unlikely to occur.

  The double hull structure of the first invention is a double ship bottom in which the ship bottom is constituted by a ship bottom skin and an inner bottom plate, and the ship side is a double ship side constituted by a ship side skin and a double ship side wall, A bilge hopper part is formed between the double ship bottom and the double ship side, the bilge inner plate of the bilge hopper part is formed in a curved shape, and the joint part with the inner bottom plate and the double ship side wall It is characterized in that the joint is joined so as not to make an angle.

  According to the first aspect of the invention, since the bilge inner plate of the bilge hopper is curved, it can be joined to the vessel bottom inner plate and the double ship side wall at an angle, so that stress is not concentrated on the joint. Therefore, deformation and damage are less likely to occur due to the external force applied to the ship bottom. Moreover, since the width dimension in the corner in a tank spreads, a cargo volume can be enlarged.

Next, a double hull structure according to an embodiment of the present invention will be described.
FIG. 1 is a half sectional view of a center part of a hull of an oil tank ship according to an embodiment of the present invention, and FIG. 2 is a half sectional view of a front and rear part of the hull in the oil tank ship.

As shown in FIG. 1, the ship bottom is a double ship bottom composed of a ship bottom skin 11 and an inner bottom plate 12, and the ship side is a double ship side composed of a ship side skin 13 and a double ship side wall 14. And the bilge hopper part 20 is formed between the said double ship bottom and the said double ship side.
The bilge hopper 20 is formed by a bilge outer plate 21 and a bilge inner plate 22. The bilge skin 21 is curved like the conventional structure, and is connected to the ship bottom skin 11 and the ship side skin 13.

The bilge inner plate 22 is a characteristic part of the present invention and is a curved plate material. When this curved bilge inner plate 22 is used, the joint portion with the inner bottom plate 12 can be smoothly connected without an angle. Moreover, the joint part with the double ship side wall 14 can also be smoothly connected in a state where there is no angle.
In the joint between the bilge inner plate 22 and the inner bottom plate 12, when the height d of the double ship bottom is 1150 mm, which is the same as the conventional example of FIG. 3, r is large, for example, 700 mm, so the stress concentration coefficient is 1.18. It becomes. That is, it is a little less than one-third that of the conventional example in FIG.

  Further, as shown in FIG. 2, a curved plate material obtained by bending the bilge inner plate 22b so as to be parallel to the bilge outer plate 21b is used at the front and rear portions of the hull, and the inner bottom plate 12 and the double ship side wall 14 are provided. It can be connected smoothly so that there is no angle.

  As described above, since the two joint portions of the bilge inner plate 22 are smoothly joined, stress does not concentrate, and deformation and damage are less likely to occur due to an external force applied to the ship bottom. Moreover, since the width dimension of the double part in the corner in a tank becomes small, a cargo volume can be enlarged.

It is a half sectional view of the hull center part of the oil tank ship concerning one embodiment of the present invention. It is a half sectional view of the hull front-rear part in the oil tank ship. It is a half sectional view of the hull center part in the conventional oil tank ship.

Explanation of symbols

11 Ship bottom skin 12 Inner bottom plate 13 Ship side skin 14 Double ship side wall 21 Bilge skin 22 Bilge skin

Claims (1)

The ship bottom is a double ship bottom composed of a ship bottom skin and an inner bottom plate, and the ship side is a double ship side composed of a ship side skin and a double ship side wall, between the double ship bottom and the double ship side A bilge hopper is formed,
A double ship characterized in that a bilge inner plate of the bilge hopper is formed in a curved shape, and is joined so as not to be angled at a joint portion with the ship bottom inner plate and a joint portion with the double ship side wall. Shell structure.