Porous-structure device for suppressing wave run-up and design method thereof

Patent metadata

Field	Value
Publication number	US-11254398-B2
Application number	US-202016934037-A
Country	US
Kind code	B2
Filing date	Jul 21, 2020
Priority date	Aug 1, 2018
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

A porous-structure device includes a semi-submersible platform consisting of four columns, two pontoons, two horizontal supports and a deck. Fillets on middle portions of the columns have a square section, a radius of the fillets, close to the deck and the pontoons, of the columns is gradually decreased to 0, a porous device is disposed outside each column and is formed by combining and connecting four single components, and each single component is formed by combining and connecting a plurality of porous laminated plates and a plurality of connecting pieces. The parameters, such as the pore type, porosity, number of layers, interlayer spacing and installation height, of the porous laminated plates are set according to the wave characteristics in different sea areas.

First claim

What is claimed is:

1. A porous-structure device for suppressing wave run-up, the porous-structure device comprising a marine platform consisting of four columns, two pontoons, four horizontal supports and a deck, wherein fillets on middle portions of the columns have a square section, and a radius of the fillets, close to the deck and the pontoons, of the columns is gradually decreased to 0; two sliding grooves are concavely and vertically formed in each of four sides of each of the columns, and connecting blocks are slidably arranged in the sliding grooves;
a porous device is disposed outside each of the columns and is formed by combining and connecting four single components, and each of the single components is formed by combining and connecting a plurality of porous laminated plates and a plurality of connecting pieces; and
a plurality of through holes penetrate through surfaces of the porous laminated plates, the plurality of porous laminated plates are arranged in parallel, 45° internal unfilled corners are formed at ends of two sides of each of the porous laminated plates, and the four single components are arrayed in a square shape to form the porous device and are disposed outside each of the columns.

2. The porous-structure device for suppressing wave run-up according to claim 1 , wherein the marine platform is a semi-submersible platform.

3. The porous-structure device for suppressing wave run-up according to claim 1 , wherein the porous laminated plates and the connecting pieces are all made of steel.

4. The porous-structure device for suppressing wave run-up according to claim 1 , wherein the connecting pieces are of a strip-shaped structure, and the plurality of connecting pieces are welded between every two adjacent of the porous laminated plates.

5. The porous-structure device for suppressing wave run-up according to claim 1 , wherein fixing plates are connected to upper ends of the single components through the connecting pieces, and each of the fixing plates has two first screwed-connection holes penetrating therethrough; and
two connecting lugs protrude on each of four sides of a top portion of each of the columns, each of the connecting lugs has a second screwed-connection hole penetrating therethrough, and each of the connecting blocks has a third screwed-connection hole penetrating therethrough; the first screwed-connection holes, the second screwed-connection holes and the third screwed-connection holes are mutually matched; and the connecting lugs, the connecting blocks and the fixing plates are fastened with bolts to ensure that the porous-structure device is fixed at the columns and is located below the deck.

6. The porous-structure device for suppressing wave run-up according to claim 4 , wherein inner walls of the first screwed-connection holes, the second screwed-connection holes and the third screwed-connection holes are of a threaded structure.

7. The porous-structure device for suppressing wave run-up according to claim 1 , wherein adapter plates are welded to ends of inner sides of the porous laminated plates of the single components, and the adapter plates are triangular and have arc notches matched with the fillets of the columns.

8. A design method of the porous-structure device for suppressing wave run-up according to claim 1 , the design method comprising the following steps:
S1: brief summary of test preparations, wherein the preparation includes preparing a water pool having a length of 50 m, a width of 40 m and a depth of 10 m and configured with a liftable false bottom to simulate any water depths from 0 m to 9.8 m for a test, wherein two multi-unit wave generation systems are separately configured on two sides of the water pool, and a ship-type semi-submersible platform including four columns, two pontoons and a deck is used as a test model, wherein fillets on middle portions of the columns have a square section, and a radius of the fillets close to the deck and the pontoons is gradually decreased to 0;
S2: comprehensively considering all factors comprising sizes of the semi-submersible platform, dimensions of a marine engineering deep pool, a simulation capacity of a marine environment and a measuring range of measurement instruments used in the test, determining a scale ratio λ of the model adopted in the test to be 60, comparing and analyzing a pore performance of the platform before installation of additional porous structures on the columns and a pore performance of the platform after installation of the additional porous structures on the columns in five wave environments, and then determining parameters of the porous structures;
S3: designing sizes of the porous structures based on the platform, wherein the designing includes according to a draft of the platform, a height of the columns and a height of a lower deck, determining a total number of the porous laminated plates to be 10, an interlayer spacing between the porous laminated plates to be 0.6 m, a distance from an installation height of a bottommost porous laminated plate to a baseline to be 30.5 m, and a distance from a topmost porous laminated plate to the lower deck to be 0.6 m; wherein sizes of corresponding models are as follows: the interlayer spacing is 10 mm, and the distance from the topmost porous laminated plate to the lower deck is 10 mm; under a survival load condition, a distance from bottom surfaces of the additional porous structures to a calm water line is 11 m, so that interaction with waves is basically avoided, and a hydrodynamic performance of the platform in normal operation will not be affected; a thickness value of the additional porous structures on the columns is 10% of a width of the columns, and comprehensively considering a height and thickness distribution of typical run-up water jets along the columns, wherein 10% of the width of the columns of the platform model is 1.825 m; as for a four-column gravity-type platform, a typical thickness of wave run-up water flows along surfaces of the columns close to the lower deck is about 1 m-1.5 m; and under the comprehensive considerations, the thickness of the additional porous structures on the columns is set to 1.5 m, and a corresponding model value is 25 mm; and
S4: determining parameters of the porous laminated plates, wherein the determination includes comprehensively considering a machining process of the additional structure models, material strength and porosity, setting a dimension of pores to 5.5 mm*3.5 mm, wherein an edge spacing between the pores in a width direction is 2 mm; and in a thickness direction, the pores are arrayed in four rows, an edge spacing between the pores is 2.2 mm, and an overall porosity is about 41.1%.

Assignees

• Univ Shanghai Jiaotong

Inventors

• Xiao Longfei
• Fang Zhichao
• Li Haobo
• Kou Yufeng
• Liu Mingyue
• Wei Handi
• Zhao Guocheng

Classifications

• B63B35/44 Primary

  Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices {(construction methods for floating offshore platforms B63B75/00)} · CPC title

• B63B1/107

  Semi-submersibles; Small waterline area multiple hull vessels and the like, e.g. SWATH · CPC title

• B63B71/20 Primary

  using towing tanks or model basins for designing · CPC title

• B63B2017/009

  Wave breakers, breakwaters, splashboards, or the like · CPC title

• B63B39/005

  Equipment to decrease ship's vibrations produced externally to the ship, e.g. wave-induced vibrations (propulsion mountings for anti-vibration purposes B63H21/30; vibration dampers, suppression of vibration in systems F16F) · CPC title