CN112849352A

CN112849352A - Cylindrical floating body horizontal truss optimized structure

Info

Publication number: CN112849352A
Application number: CN202110125107.9A
Authority: CN
Inventors: 杨玥; 刘亚冲; 王璞
Original assignee: 708th Research Institute of CSIC
Current assignee: 708th Research Institute of CSIC
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2021-05-28

Abstract

The invention relates to a cylindrical floating body horizontal truss optimized structure which is characterized by comprising a radial vertical perforated bulkhead structure arranged in each sub-outer ballast water tank, a section of horizontal truss I arranged on each radial vertical perforated bulkhead structure, a back bracket plate arranged on each bulkhead II and a section of horizontal truss II arranged on each bulkhead II. The hull weight is greatly optimized according to the horizontal truss structure optimized according to the stress transfer path, and compared with the total weight of the horizontal truss structure before optimization, the overall weight of the optimized horizontal truss structure is reduced by 30-40% under the equivalent structural stress level; the horizontal truss structure optimized according to the stress transmission path greatly optimizes the stress distribution and the stress extreme value of the ship body, effectively decomposes the stress concentration phenomenon of the structure, has more even stress distribution, reduces the stress concentration problem of the opening corners of the horizontal truss, and reduces the stress by 20 to 40 percent under the same thickness of the component.

Description

Cylindrical floating body horizontal truss optimized structure

Technical Field

The invention relates to a cylindrical floating body horizontal truss structure designed by using a topological optimization method, and belongs to the field of ship and ocean engineering.

Background

Because the reserves are abundant, the exploitation to marine oil has continuously increased in recent years, but because the marine environment is complicated, the exploitation degree of difficulty is great, leads to the exploitation cost higher, has greatly restricted marine oil's exploitation. Therefore, it is becoming more and more important to design more optimized offshore oil production equipment.

Currently, the mainstream offshore oil exploitation equipment in the world mainly comprises an offshore platform and a floating body. Among them, the cylindrical hull has better hydrodynamic performance than the conventional boat-type hull, and does not rely on a single point turret device, and has become more and more popular with ocean design practitioners in recent years. However, how to optimize the structural form of the cylindrical floating body can make the cylindrical floating body have lighter weight and more economic advantages on the basis of better structural strength and rigidity performance, and becomes a very troublesome problem.

For the structural design of the cylindrical floating body, the stress form caused by the appearance is greatly different from that of the traditional ship type, the local strength of the deep cabin replaces the total longitudinal strength to become the main control load of the floating body, the horizontal truss arranged on the cabin wall is used as a strong component for supporting the vertical strengthening material of the deep cabin, the local design load is very large, and external waves and the pressure of the internal deep cabin also need to be transmitted. In addition, the through-holes of the inspection channels need to be opened on the horizontal girders, which causes the problem of local structural stress concentration at the corners of the opened horizontal girders and brings many challenges to the design of the horizontal girder structure.

At present, the conventional technology is adopted, the horizontal trusses are directly subjected to component size design according to cabin arrangement and are reinforced in a local stress larger area, and a structurally effective stress transfer path is not considered, so that the following problems are brought about: 1. the horizontal truss span is large, and the size requirement of the component is large; 2. the stress distribution of the horizontal trusses is unbalanced and is concentrated around the opening and at the toe end of the transition toggle plate, the deformation of the bulkhead is large, and the structural strength and the fatigue performance are to be improved; 3. the two points result in that the weight of the structural steel material is larger, the cost is higher, and the storage capacity index of the cargo oil tank is reduced.

In summary, the main problem of the present cylindrical floating body is that the horizontal truss structure designed by the conventional method is not suitable for the cylindrical floating body.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the horizontal truss structure of the internal bulkhead of the cylindrical floating body is designed more conventionally, so that the horizontal truss structure is not effectively utilized, the structure is heavy and has local stress concentration.

In order to solve the technical problems, the technical scheme of the invention is to provide a horizontal truss optimization structure of a cylindrical floating body, wherein the cylindrical floating body comprises an external pressure loading water tank, an oil tank, an internal pressure loading water tank or an internal oil tank and a moon pool or an intermediate empty tank which are arranged from outside to inside, the external pressure loading water tank and the oil tank are separated by a ballast water tank inner plate and an oil tank outer plate, the oil tank and the internal pressure loading water tank or the internal oil tank are separated by an oil tank inner plate, the internal pressure loading water tank or the internal oil tank and the moon pool or the intermediate empty tank are separated by a moon pool area wall plate, a floating body ballast water tank outer plate is arranged outside the external pressure loading water tank, the external pressure loading water tank is divided into 2N external pressure loading water tanks by a bulkhead I, the oil tank is divided into N cargo oil tanks by a bulkhead II, N is not less than 2, and the horizontal truss optimization structure comprises a radial vertical perforated bulkhead structure arranged in each external pressure loading water tank, the first horizontal truss section is arranged on each radial vertical open-pore bulkhead structure, the back elbow plate is arranged on each second bulkhead, and the second horizontal truss section is arranged on each second bulkhead.

Preferably, the N cargo tanks are equiangularly arranged along the center of the cylindrical floating body.

Preferably, the N horizontal girders are arranged at equal angles along the center of the cylindrical floating body.

Preferably, the radial vertical open bulkhead structure and the horizontal truss thereon are positioned in the middle of each sub-outer pressure water carrying tank.

Preferably, a first inclined strut is arranged on the back toggle plate.

Preferably, a second inclined strut is arranged on the second horizontal truss and close to the inner plate of the ballast water tank and the outer plate of the oil tank.

Preferably, one end of the second inclined strut is supported at the intersection of the radial vertical perforated bulkhead structure and the inner and outer ballast water tank plates, and the other end of the second inclined strut is supported at the intersection of the second bulkhead and the first inclined strut.

Preferably, the arrangement angle range of the second inclined strut and the inner plate of the ballast water tank and the outer plate of the oil tank is 120-135 degrees.

Preferably, a first opening is formed in a closed area surrounded by the second inclined strut, the second bulkhead and the inner and outer plates of the ballast water tank.

Preferably, the back toggle plate is provided with a second opening.

Compared with the prior art, the invention has the following beneficial effects:

1) the weight of the ship body is greatly optimized according to the horizontal truss structure optimized according to the stress transfer path, and according to preliminary estimation, the overall weight of the optimized horizontal truss is reduced by 30-40% under the equivalent structural stress level compared with the total weight of the horizontal truss structure before optimization;

2) the horizontal truss structure optimized according to the stress transmission path greatly optimizes the stress distribution and the stress extreme value of the ship body, effectively decomposes the stress concentration phenomenon of the structure, has more even stress distribution, reduces the stress concentration problem of the opening corners of the horizontal truss, and reduces the stress by 20 to 40 percent under the same thickness of the component;

3) the opening structure of the horizontal truss can be set as a ladder way opening, and the total arrangement and the structural design of the floating body are greatly optimized.

Drawings

FIG. 1 is a side view of a cylindrical buoyant body and a layout of horizontal girders;

FIG. 2 is a view of the arrangement of the horizontal girders and bulkheads (FIG. 1, a detail view of a portion of the same);

FIG. 3 is a view of the cabin layout;

FIG. 4 illustrates a conventional cylindrical float reinforcement;

FIG. 5 is a stress transmission path for a finite element simulation;

FIG. 6 is a horizontal truss optimized structure;

fig. 7 shows the final optimized layout of the horizontal truss structure 1.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

With reference to fig. 1 and 2, the horizontal truss structures 1 are uniformly arranged according to the rotation of the bulkheads of the ship body, and the open pore structure formed by the horizontal truss structures 1 and the bulkheads of the ship body on each layer is fixed in the horizontal direction and can be used as a ladder way of the floating body, so that the total arrangement and the structural design of the floating body are optimized. In the present embodiment, the internal chamber of the cylindrical floating body is divided into an external pressure water-carrying tank, an oil tank, an internal pressure water-carrying tank, and a moon pool (or an intermediate empty tank without a moon pool, the present embodiment further describes the present invention by taking the moon pool as an example) by the floating body water ballast tank outer plate 2, the water ballast tank inner plate and oil tank outer plate 3, the oil tank inner plate 4, and the moon pool area tank wall plate 5. In fig. 2,

reference numerals

6, 7, and 8 denote bulkheads arranged in a water tank without internal pressure loading or an internal oil tank, where 6 denotes a moon pool bulkhead, 7 denotes a water ballast tank inner plate and an oil tank outer plate, and 8 denotes a floating body water ballast tank outer plate.

Referring to fig. 3, the optimized number and distribution of the horizontal girders are determined according to the cabin layout of the cylindrical floating body, wherein the oil tank of the cylindrical floating body proposed by the embodiment is divided into 8 cargo tanks by a bulkhead two 15, and the 8 cargo tanks are arranged along the center of the cylinder at equal angles. And the outer ballast water tank is divided into 16 sub-outer ballast water tanks by the first bulkhead 11, 12.

As shown in fig. 4, the conventional cylindrical floating body is reinforced by: for the external pressure water-carrying tank, the reinforcing form is mainly a form of truss and elbow plate, for example, a horizontal truss structure is arranged in the spaces of the adjacent first bulkhead 11, first bulkhead 12, outer plate 2 of the floating body water ballast tank and inner plate 3 of the water ballast tank and oil tank. The toggle 14 is then positioned outside the outer ballast tank to ensure that the tank wall is sufficiently rigid when subjected to a load. The structure of this type can generally satisfy the strength requirement, but since the transmission path of the load acting on the cylindrical floating body is not considered, the size of the general structural member is large, the weight of the redundant hull member is large, and the weight of the hull is greatly increased in order to ensure the structural strength and rigidity.

According to the invention, finite element software approved by classification society is used for carrying out simulation calculation according to the set loading working condition to obtain a stress transmission path, and a reinforced horizontal truss structure is arranged according to the transmission path. The optimized horizontal truss structure is mainly distributed in the oil tank and forms effective support for the ballast water tank. Fig. 5 illustrates the stress transmission path of the horizontal girder under the design condition, and the resulting cabin structure is shown in fig. 6 with the stress transmission path being sufficiently considered.

According to the figure 6, a radial vertical perforated bulkhead structure 16 is additionally arranged in the space of a first bulkhead 11, a first bulkhead 12, a floating body water ballast tank outer plate 2 and a water ballast tank inner plate and oil tank outer plate 3, and a section of horizontal truss I19 is additionally arranged on the radial vertical perforated bulkhead structure 16, so that the supporting rigidity of a strong member of the outer plate can be effectively increased, and the water pressure of the outer plate and the deep tank load of the water ballast tank and the oil tank can be effectively transmitted. In addition, a second bracing 18 is arranged on the horizontal truss 13 of the second bulkhead 15 near the inner and outer ballast water tank plates 3. The number of the horizontal girders 13 is 8, and the horizontal girders are arranged along the center of the cylinder at equal angles. One end of the second diagonal brace 18 is supported at the intersection of the radial vertical open-hole bulkhead structure 16 and the inner and outer ballast tank plates 3, and the other end is supported at the intersection of the second bulkhead 15 and the first diagonal brace arranged on the toggle plate 14 on the back of the second bulkhead. The arrangement angle range of the second inclined strut 18 and the inner plate of the ballast water tank and the outer plate 3 of the oil tank is 120-135 degrees. The closed area surrounded by the second inclined strut 18, the second cabin wall 15 and the inner and outer ballast water cabin plates 3 is provided with an opening I, and the opening I can be set as an access passage opening. The back toggle plate 14 of the bulkhead two 15 has the same brace one 14 and opening two, optimizing the arrangement and structural design of the floating body.

The invention is provided with two horizontal girders (a first horizontal girder 19 and a second horizontal girder 13), and a radial vertical perforated bulkhead structure 16 and a first horizontal girder 19 thereof are arranged in the middle of each ballast water tank; and another horizontal truss, namely a second horizontal truss 13, is arranged outside the internal pressure water carrying tank for providing support for the external pressure water carrying tank. The angle range of the two horizontal trusses is 120-135 degrees.

Claims

1. A cylindrical floating body horizontal truss optimization structure comprises an external pressure water-carrying cabin, an oil cabin, an internal pressure water-carrying cabin or an internal oil cabin and a moon pool or an intermediate hollow cabin which are arranged from outside to inside, wherein the external pressure water-carrying cabin is separated from the oil cabin through a water ballast cabin inner plate and an oil cabin outer plate, the oil cabin is separated from the internal pressure water-carrying cabin or the internal oil cabin through an oil cabin inner plate, the internal pressure water-carrying cabin or the internal oil cabin is separated from the moon pool or the intermediate hollow cabin through a moon pool area cabin wall plate, a floating body water ballast cabin outer plate is arranged outside the external pressure water-carrying cabin, the external pressure water-carrying cabin is divided into 2N external pressure water-carrying cabins through a first cabin wall, the oil cabin is divided into N cargo oil cabins through a second cabin wall, N is more than or equal to 2, the horizontal truss optimization structure comprises a radial vertical perforated cabin wall structure arranged in each sub external pressure water-carrying cabin, and a section of a horizontal truss structure arranged on each radial vertical perforated cabin wall, the back toggle plate is arranged on each bulkhead II, and the horizontal truss II is arranged on each bulkhead II.

2. The optimal structure of the horizontal truss of cylindrical floating body as claimed in claim 1, wherein said N cargo tanks are equiangularly arranged along the center of the cylindrical floating body.

3. The optimized structure of the cylindrical floating body horizontal truss as claimed in claim 1, wherein N horizontal trusses are arranged at equal angles along the center of the cylindrical floating body.

4. The optimized structure of cylindrical floating body horizontal truss as claimed in claim 1, wherein said radial vertical perforated bulkhead structure and said horizontal truss thereon are located in the middle of each of said sub-external pressure carrying water tanks.

5. The optimized structure of cylindrical floating body horizontal truss as claimed in claim 1, wherein said back toggle plate is provided with a first inclined strut.

6. The optimized structure of cylindrical floating body horizontal truss as claimed in claim 5, wherein a second inclined strut is arranged on the second horizontal truss near the inner plate of the ballast water tank and the outer plate of the oil tank.

7. The optimized structure of cylindrical floating body horizontal truss as claimed in claim 6, wherein one end of said second inclined strut is supported at the intersection of said radial vertical open bulkhead structure and said inner and outer ballast water tank plates, and the other end is supported at the intersection of said second bulkhead and said first inclined strut.

8. The optimized structure of the cylindrical floating body horizontal truss as claimed in claim 6, wherein the arrangement angle range of the second inclined strut and the inner plate of the ballast water tank and the outer plate of the oil tank is 120-135 °.

9. The optimized structure of the cylinder type floating body horizontal truss as claimed in claim 5, wherein the closed area enclosed by the second inclined strut, the second bulkhead and the inner and outer plates of the ballast water tank is provided with a first opening.

10. The optimized structure of cylindrical floating body horizontal truss as claimed in claim 1, wherein said back toggle plate is provided with a second opening.