Reinforcing method for small corner opening in FPSO high-stress area

Abstract

The invention relates to the technical field of ocean engineering structure fatigue strength design, and discloses an FPSO high-stress area small corner opening reinforcing method which comprises the following steps that S1, a first opening is formed in a mother board, and the corner radius of the first opening meets the structural strength requirement; s2, a web plate is attached to the surface of the mother board, and the thickness of the web plate is consistent with that of the mother board; s3, forming a second open hole in the web plate, wherein the size of the second open hole is smaller than that of the first open hole; and S4, an MCT cable frame is installed on the inner wall of the second open hole of the web plate. According to the reinforcing method for the small corner opening in the FPSO high-stress area, a first opening which is a large hole is formed in a mother board to meet the strength requirement, and then a second opening which is actually needed is formed in a web. According to the structure, the problem of stress concentration caused by forming the right-angle small corner on the mother board can be reduced, and the mother board is prevented from being torn.

Description

Technical Field

[0001] This invention relates to the field of fatigue strength design technology for marine engineering structures, specifically a reinforcement method for small corner openings in the high stress zone of FPSOs. Background Technology

[0002] FPSO stands for Offshore Area or Special Area, a special area of ​​an offshore platform structure. It is a floating platform that integrates crude oil production, storage, and unloading functions. Its deck structure is subjected to complex environmental loads such as wind, waves, and currents for a long time, resulting in high-stress zones in specific areas, such as bulkhead joints and equipment support points. In these areas, electrical engineers need to install MCT, or Multi-Cable Transit, a sealed frame structure used to penetrate bulkheads to ensure watertightness, fire resistance, and electromagnetic shielding performance of cables when they pass through.

[0003] Traditional MCT openings are designed with small right-angle corners. If the corner radius is less than R12, the dynamic fatigue load in the high-stress area will cause severe stress concentration at such small-radius corners, leading to the risk of structural tearing of the base material. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a reinforcement method for small corner openings in high-stress areas of FPSOs, thus solving the problems mentioned in the background.

[0005] This invention provides the following technical solution: a method for reinforcing small corner openings in high-stress areas of FPSOs, comprising the following steps:

[0006] Step S1: Open a first opening on the mother plate, wherein the corner radius of the first opening meets the structural strength requirements;

[0007] Step S2: Attach the web plate to the surface of the mother plate, wherein the thickness of the web plate is the same as that of the mother plate;

[0008] Step S3: A second opening is made on the web plate, the size of the second opening being smaller than that of the first opening;

[0009] Step S4: Install the MCT cable frame on the inner wall of the second opening of the web.

[0010] Preferably, the shape of the first opening is circular, oval, or rectangular;

[0011] The shape of the web is the same as that of the first opening, and the web covers the entire area of ​​the first opening.

[0012] Preferably, the distance between the outer contour edge of the web and the edge of the first opening is ≥20mm.

[0013] Preferably, the corner radius R of the second opening is ≥12mm.

[0014] Preferably, in step S2, the web plate and the mother plate are fixedly connected by welding;

[0015] Furthermore, the web plate is welded to the base plate using a continuous fillet weld or a bevel weld, with the welding position located at the contact edge between the web plate and the base plate.

[0016] Preferably, in step S4, the MCT cable frame and web are pre-welded and installed in the workshop.

[0017] Preferably, step 5 is also included: packaging the welded mother plate, web plate and MCT cable frame as a whole for segmented pre-outfitting.

[0018] Preferably, the mother plate is located in the high-stress zone or fatigue load zone of the offshore platform.

[0019] Preferably, the cutting of the first opening, the second opening, and the web is all completed by CNC cutting.

[0020] Preferably, the MCT cable frame is used for electrical engineering cable routing within a compartment.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention first creates a large opening in the mother plate to meet strength requirements, and then creates a second opening in the web as needed. This structure reduces stress concentration caused by creating small right-angle corners in the mother plate, preventing the mother plate from tearing.

[0023] 2. The present invention ensures the continuity of stiffness by designing the web and the base plate to be of equal thickness, thus avoiding abrupt changes in stiffness in the reinforcement zone.

[0024] 3. This invention enables segmented pre-outfitting by pre-installing the MCT cable frame and web plate in the workshop, saving on-site installation time. Attached Figure Description

[0025] Figure 1 This is a flowchart of the present invention;

[0026] Figure 2 This is a side sectional view of the present invention;

[0027] Figure 3 This is a schematic diagram showing that the first opening and the web of the present invention are circular structures;

[0028] Figure 4 This is a schematic diagram of the first opening and the web of the present invention having an oval structure;

[0029] Figure 5 This is a schematic diagram of the first opening and the web of the present invention, which are rectangular structures.

[0030] In the diagram: 1. Mother plate; 2. First opening; 3. Web plate; 4. Second opening; 5. MCT cable frame. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figure 1-5 The reinforcement method for small corner openings in high-stress areas of FPSOs includes the following steps:

[0033] Step S1: A first opening 2 is made on the mother plate 1, and the corner radius of the first opening 2 meets the structural strength requirements.

[0034] Step S2: Attach the web plate 3 to the surface of the mother plate 1, with the thickness of the web plate 3 being the same as that of the mother plate 1.

[0035] Step S3: A second opening 4 is made on the web 3, and the size of the second opening 4 is smaller than that of the first opening 2.

[0036] Step S4: Install the MCT cable frame 5 on the inner wall of the second opening 4 of the web plate 3.

[0037] Please see Figure 3-5 The first opening 2 is circular, oval, or rectangular in shape, and the shape of the web 3 is the same as that of the first opening 2, and the web 3 covers the entire area of ​​the first opening 2.

[0038] The distance between the outer contour edge of the web 3 and the edge of the first opening 2 is ≥20mm, and the corner radius R of the second opening 4 is ≥12mm.

[0039] In step S2, the web plate 3 and the mother plate 1 are fixedly connected by welding, and the welding of the web plate 3 and the mother plate 1 is a continuous fillet weld or a bevel weld, with the welding position located at the contact edge of the web plate 3 and the mother plate 1.

[0040] In step S4, the MCT cable frame 5 and the web plate 3 are pre-welded and installed in the workshop.

[0041] It also includes step 5: packaging the welded mother plate 1, web plate 3 and MCT cable frame 5 as a whole for segmented pre-outfitting.

[0042] The mother plate 1 is located in the high stress area or fatigue load area of ​​the offshore platform. The cutting of the first opening 2, the second opening 4 and the web plate 3 are all completed by CNC cutting. The MCT cable frame 5 is used for electrical professional cables to pass through the cabin.

[0043] First, a large hole, 2, is drilled in the mother plate 1 to meet strength requirements. Then, a second hole, 4, is drilled in the web plate 3 as needed. This structure reduces stress concentration caused by drilling small right-angle corners in the mother plate 1, preventing the mother plate 1 from tearing. The web plate 3 is designed to be the same thickness as the mother plate to ensure stiffness continuity and avoid abrupt changes in stiffness in the reinforced area. The MCT cable frame 5 and the web plate 3 are pre-installed in the workshop, realizing segmented pre-outfitting. This transforms the drilling operation in high-stress areas from shipboard construction to standardized workshop operations, eliminating the need for secondary reinforcement on-site. Segmented pre-outfitting saves on-site installation time. The first hole 2 and the second hole 4 are CNC-cut to reduce drilling accuracy errors.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A reinforcement method for small corner openings in high-stress areas of an FPSO, characterized in that, Includes the following steps: Step S1: A first opening (2) is made on the mother plate (1), and the corner radius of the first opening (2) meets the structural strength requirements; Step S2, attach the web plate (3) to the surface of the mother plate (1), wherein the thickness of the web plate (3) is the same as that of the mother plate (1); Step S3: A second opening (4) is made on the web (3), the size of the second opening (4) being smaller than that of the first opening (2); Step S4: Install the MCT cable frame (5) on the inner wall of the second opening (4) of the web plate (3).

2. The reinforcement method for small corner openings in high-stress areas of FPSOs according to claim 1, characterized in that, The shape of the first opening (2) is circular, oval, or rectangular; The shape of the web (3) is the same as that of the first opening (2), and the web (3) covers the entire area of ​​the first opening (2).

3. The reinforcement method for small corner openings in high-stress areas of FPSO according to claim 2, characterized in that, The distance between the outer contour edge of the web (3) and the edge of the first opening (2) is ≥20mm.

4. The reinforcement method for small corner openings in high-stress areas of FPSOs according to claim 1, characterized in that, The corner radius R of the second opening (4) is ≥12mm.

5. The reinforcement method for small corner openings in high-stress areas of FPSOs according to claim 1, characterized in that, In step S2, the web plate (3) and the mother plate (1) are fixedly connected by welding; Furthermore, the web plate (3) and the mother plate (1) are welded by a continuous fillet weld or a bevel weld, and the welding position is located at the contact edge between the web plate (3) and the mother plate (1).

6. The reinforcement method for small corner openings in high-stress areas of FPSOs according to claim 1, characterized in that, In step S4, the MCT cable frame (5) and the web plate (3) are pre-welded and installed in the workshop.

7. The reinforcement method for small corner openings in high-stress areas of FPSOs according to claim 1, characterized in that, It also includes step 5: packaging the welded mother plate (1), web plate (3) and MCT cable frame (5) as a whole for segmented pre-outfitting.

8. The reinforcement method for small corner openings in high-stress areas of FPSOs according to claim 1, characterized in that, The mother plate (1) is located in the high stress zone or fatigue load zone of the offshore platform.

9. The reinforcement method for small corner openings in high-stress areas of FPSOs according to claim 1, characterized in that, The cutting of the first opening (2), the second opening (4) and the web (3) is all completed by CNC cutting.

10. The reinforcement method for small corner openings in high-stress areas of FPSOs according to claim 1, characterized in that, The MCT cable frame (5) is used for electrical engineering cables to pass through the compartment.

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