A method for arranging a LNG carrier's main deck bend structure

Abstract

The application provides a method for arranging a LNG ship main deck bending structure, comprising the following steps: step 1, arranging the main deck and its longitudinal frame: the ship middle section main deck adopts a bending arrangement, the ship bow section and the ship stern section main deck adopt a straight arrangement, and a transition arrangement is adopted between the bending arrangement and the straight arrangement; step 2, arranging the upper longitudinal frame and the lower longitudinal frame of the diagonal side plate: in the bending arrangement and the transition arrangement, the diagonal side plate is changed into a full longitudinal frame structure, and a diagonal side longitudinal frame is additionally arranged at the connection between the main deck before bending and the diagonal side plate; step 3, arranging the outfitting platform: an outfitting platform is additionally arranged between every two strong frame sections; step 4, optimizing the manhole arrangement: the first manhole position on the strong frame is lifted to the direction of the inclined dome deck and is translated to the ship inner side direction to obtain the second manhole position, and the manhole is rearranged according to the second manhole position. The application greatly reduces the number of structural parts, reduces the structural self weight, and reduces the labor cost of construction.

Description

Technical Field

[0001] This invention relates to the field of ship design and manufacturing technology, and specifically to an arrangement method applicable to the bent structure of the main deck of an LNG ship. Background Technology

[0002] In the main deck area of ​​an LNG carrier, the traditional straight layout creates an acute angle between the main deck and the diagonal sideboards. Due to the extremely limited space at this angle, longitudinal skeletons cannot be installed, necessitating a transverse frame structure. This structure requires several elbow plates to be installed between the main deck longitudinal skeletons and the diagonal sideboard longitudinal skeletons below the main deck, such as... Figure 1 As shown, this not only increases the number of parts, but also greatly increases the difficulty of construction because the operating space at the angle is too narrow.

[0003] Furthermore, in the space formed by the sideboard and the sloping dome deck above the main deck, manholes must be installed on the strong frame in this area to meet passage requirements. However, due to limited space, the manholes can only be located close to the deck. This arrangement results in the manholes being very close to the longitudinal rib through holes of the sideboard, weakening the local structural strength. Therefore, the design requires the addition of watertight reinforcement plates near the manholes at the longitudinal rib through holes of the sideboard to strengthen the structure. This further increases the number of structural parts and the length of welding, thus significantly increasing construction time and workload. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an arrangement method suitable for the bent structure of the main deck of an LNG ship.

[0005] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0006] A method for arranging the bent structure of the main deck of an LNG carrier includes the following steps:

[0007] Step 1, Main Deck and its longitudinal arrangement: The main deck in the midship section adopts a bent arrangement, while the main decks in the bow and stern sections adopt a straight arrangement. A transition arrangement is used between the bent and straight arrangements. In the bent arrangement, the main deck bends downward along the first bend line near the end longitudinal rib, and the bent section of the main deck is perpendicular to the side plate. In the transition arrangement, a second bend line is designed based on the connection position between the main deck and the side plate in the bent arrangement and the connection position between the main deck and the side plate in the straight arrangement. The main deck bends along the second bend line to achieve the connection between the bent and straight arrangements.

[0008] Step 2, Arrangement of upper and lower longitudinal ribs of the sideboard: In the bending and transition arrangements, the elbow plate at the connection between the main deck and the sideboard is removed, and the sideboard is changed to a full longitudinal frame structure. An additional sideboard longitudinal rib is added at the connection between the main deck and the sideboard before bending. At the same time, the sideboard located in the ballast tank area below the main deck after bending is equipped with a lower longitudinal rib, and the sideboard located in the empty tank area above the main deck is equipped with an upper longitudinal rib.

[0009] Step 3, Outfitting Platform Arrangement: An outfitting platform is added between every two strong frames. The outfitting platform includes a platform, two legs set at the bottom of the platform, railings set on both sides of the platform, and steps set in the middle section of the platform. The bottom end of one leg is connected to the upper longitudinal bone of the diagonal plate, and the bottom end of the other leg is connected to the bending section of the main deck.

[0010] Step 4, Manhole Optimization Arrangement: Based on the outfitting platform layout, the position of the first manhole on the strong frame is raised towards the inclined dome deck and shifted towards the inward side of the ship to obtain the position of the second manhole. The manholes are then rearranged according to the position of the second manhole.

[0011] Furthermore, the distance between the first bend line and the longitudinal rib at the end of the main deck is 20mm.

[0012] Furthermore, no longitudinal ribs are arranged in the curved section of the main deck, and the spacing between the longitudinal ribs in the straight section of the main deck is c.

[0013] Furthermore, in the bending arrangement, the length of the bending section is less than c, and in the transition arrangement, the length of the main deck is 5c.

[0014] Furthermore, the spacing between the bones of the lower longitudinal bone is a, and the spacing between the bones of the upper longitudinal bone is b, where a < b.

[0015] Furthermore, taking the direction of the straight section of the main deck as the X-axis and the direction perpendicular to the straight section of the main deck as the Y-axis, the difference in the vertical coordinate between the coordinates of the platform center point and the coordinates of the point on the straight section of the main deck is 300-400mm, and the difference in the horizontal coordinate between the coordinates of the platform center point and the coordinates of the center point of the first manhole is 200-300mm.

[0016] Furthermore, the difference in the ordinate between the center point of the second manhole and the center point of the first manhole is consistent with the difference in the ordinate between the center point of the platform and the point on the straight section of the main deck; the x-coordinate of the center point of the second manhole is consistent with the x-coordinate of the center point of the platform.

[0017] Furthermore, the second manhole is oval in shape.

[0018] Furthermore, the watertight patch plate is removed at the longitudinal bone through hole position of the diagonal plate on the strong frame, and a ground patch plate is installed instead.

[0019] The beneficial effects of this invention are as follows:

[0020] (1) After actual calculation, compared with the original design, after the main deck is bent, the horizontal frame type is changed to the longitudinal frame type at the corner of the side plate and the main deck. This can save the weight of the elbow plate caused by the horizontal frame type. At the same time, after changing to the longitudinal frame type, the number of longitudinal bones of the longitudinal frame type is significantly less than the number of elbow plates, which greatly reduces the number of structural parts and reduces the labor cost of construction.

[0021] (2) By arranging outfitting platforms and optimizing manholes, the present invention increases the passage space by taking advantage of the trend of the inclined dome deck. The watertight patch plate that originally had to be installed can be replaced with a simpler ground patch plate to meet the strength requirements, which reduces the self-weight of the structure and significantly reduces the welding length and construction time. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the straight arrangement described in this invention.

[0023] Figure 2 This is a cross-sectional view of the bending structure applicable to the main deck of an LNG ship as described in this invention.

[0024] Figure 3 This is a development diagram of the double-broken-line arrangement described in this invention.

[0025] Figure 4 This is a schematic diagram of the longitudinal arrangement of the main deck and side deck as described in this invention.

[0026] Figure 5 This is a structural diagram of the outfitting platform described in this invention.

[0027] In the diagram: 1. Main deck; 2. Side plate; 3. Longitudinal rib; 4. Lower longitudinal rib; 5. Upper longitudinal rib; 6. Outfitting platform; 61. Platform; 62. Railing; 63. Leg; 64. Step; 7. First manhole; 8. Second manhole; 9. First bend line; 10. Second bend line; 11. Elbow plate; 12. Ground patch plate; 13. Sloping dome deck. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0029] An arrangement method suitable for the bent structure of the main deck of an LNG ship, such as Figure 2 As shown, it includes the following steps:

[0030] Step 1: Arrangement of the main deck 1 and its longitudinal ribs 3. In this embodiment, the main deck 1 in the midsection of the ship is no longer arranged in a traditional straight manner, but instead bends downward along the first bending line 9 at the longitudinal rib 3 near the end of the main deck 1. The distance between the first bending line 9 and the longitudinal rib 3 at the end of the main deck 1 is 20mm. The bent section of the main deck 1 is perpendicular to the side plate 2, thus achieving a bent arrangement. The main deck 1 after bending has an overall bent structure.

[0031] like Figure 3 As shown, since the ballast tanks in the bow and stern sections are connected to the engine room and bow area respectively, the main deck 1 retains a straight arrangement in both sections. Therefore, a triangular area is formed between the bent and straight main deck 1 arrangements. Considering the continuity of the overall ship structure, a transition arrangement is adopted between the bent and straight arrangements. Specifically, the transition arrangement involves determining the connection positions of the main deck 1 and the side plate 2 in the bent arrangement, as well as the connection positions in the straight arrangement. Based on the connection positions in the bent and straight arrangements, a second bend line 10 is designed at the end of the main deck 1. The main deck 1 bends along the second bend line 10 to achieve the connection between the bend and straight arrangements, thus completing the transition arrangement. The first bend line 9 and the second bend line 10 form a double-bend line.

[0032] After the main deck 1 adopts a double-fold line form, the spacing of the longitudinal ribs 3 of the main deck 1 is set to c in the straight section other than the bending section. In this embodiment, c=810mm. The length of the bending section of the main deck 1 in the bending arrangement is set to be less than c. The length of the main deck 1 in the transition arrangement is 5c. There is no need to arrange longitudinal ribs 3 in the bending section of the main deck 1, which also avoids the cumbersome process of adding elbow plates 11 at the acute angle in the original design.

[0033] Step 2, the upper longitudinal bone 5 and lower longitudinal bone 4 of the oblique plate 2 are arranged. (As shown...) Figure 4 As shown, in the bending and transition arrangements, the bending of the main deck 1 changes the stress and connection method of the sideboard 2. Therefore, the arrangement of the skeleton in the sideboard 2 also needs to be optimized. The elbow plate 11 located at the connection between the main deck 1 and the sideboard 2 in the original design is eliminated, and the sideboard 2 is changed to a full longitudinal frame structure. Specifically, at the connection between the main deck 1 and the sideboard 2 before bending, a sideboard longitudinal skeleton is added to replace the structural function of the main deck 1 before bending. At the same time, the lower longitudinal skeleton 4 of the sideboard 2 located in the ballast tank area below the main deck 1 after bending has a skeleton spacing of a due to the greater water pressure it bears; the upper longitudinal skeleton 5 of the sideboard 2 located in the empty tank area above the main deck 1 has a skeleton spacing of b due to the less water pressure it bears, and a < b. In this embodiment, a = 760 mm and b = 815 mm. This differentiated arrangement ensures strength while avoiding material waste.

[0034] Step 3, outfitting platform 6 setup. (For example...) Figure 5 As shown, due to the inconvenience of passage through the original first manhole 7 on the strong frame after the main deck 1 is bent, this embodiment adds an outfitting platform 6 between every two strong frames. The outfitting platform 6 includes a platform 61, two legs 63 set at the bottom of the platform 61, railings 62 set on both sides of the platform 61, and steps 64 set in the middle section of the platform 61. The bottom end of one leg 63 is connected to the upper longitudinal bone 5 on the diagonal plate 2, and the bottom end of the other leg 63 is connected to the bent section of the main deck 1, making the structure stable and easy to install. The steps 64 are used for personnel to pass from the platform 61 to the main deck 1. Taking the direction of the straight section of the main deck 1 as the X-axis and the direction perpendicular to the straight section of the main deck 1 as the Y-axis, the difference in the vertical coordinate between the coordinates of the center point of the platform 61 and the coordinates of the point on the straight section of the main deck 1 is 300-400mm, and the difference in the horizontal coordinate between the coordinates of the center point of the platform 61 and the center point of the first manhole 7 is 200-300mm. The structure utilizes the orientation of the sloping dome deck 13 to create more space for passage.

[0035] Step 4, Manhole Optimization. Due to the addition of outfitting platform 6, the manhole positions on the strong frame are optimized. In this embodiment, the position of the first manhole 7 is raised towards the inclined dome deck 13 and shifted inwards to obtain the position of the second manhole 8. The manholes are then rearranged according to the position of the second manhole 8. The difference in longitudinal coordinates between the center point of the second manhole 8 and the center point of the first manhole 7 is consistent with the difference in longitudinal coordinates between the center point of platform 61 and a point on the straight section of the main deck 1; the x-coordinate of the center point of the second manhole 8 is consistent with the x-coordinate of the center point of platform 61. The second manhole 8 is oval-shaped, facilitating personnel passage. This design moves the manhole position away from the longitudinal through-hole of the oblique side plate 2, significantly increasing the distance between the manhole and the longitudinal through-hole of the oblique side plate 2, greatly improving the local structural strength of the strong frame. Therefore, the watertight patch plate, which was originally required, can be eliminated and replaced with a simpler ground-mounted patch plate 12 to meet the strength requirements. This improvement reduces the structural weight and significantly reduces welding length and construction time.

[0036] In summary, this embodiment, through the bending design of the main deck 1, combined with the offset of the outfitting platform 6 and the optimization of the manhole lifting, fundamentally eliminates the construction difficulties of traditional acute-angle structures, optimizes the passage space, simplifies the construction process, reduces the construction difficulty, and has good practical value.

[0037] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for arranging the bent structure of the main deck of an LNG ship, characterized in that, Includes the following steps: Step 1, Arrangement of main deck (1) and its longitudinal skeleton (3): The main deck (1) in the midship section adopts a bent arrangement, while the main deck (1) in the bow and stern sections adopts a straight arrangement. A transition arrangement is adopted between the bent arrangement and the straight arrangement. The bent arrangement is that the main deck (1) bends downward along the first bend line (9) near the end longitudinal skeleton (3), and the bent section of the main deck (1) after bending is perpendicular to the side plate (2). The transition arrangement is to design a second bend line (10) based on the connection position between the main deck (1) and the side plate (2) in the bent arrangement and the connection position between the main deck (1) and the side plate (2) in the straight arrangement. The main deck (1) bends along the second bend line (10) to achieve the connection between the bent arrangement and the straight arrangement. Step 2, arrangement of the upper longitudinal bone (5) and lower longitudinal bone (4) of the diagonal plate (2): In the bending arrangement and transition arrangement, the elbow plate (11) at the connection between the main deck (1) and the diagonal plate (2) is removed, and the diagonal plate (2) is changed to a full longitudinal frame structure. A diagonal longitudinal bone is added at the connection between the main deck (1) and the diagonal plate (2) before bending. At the same time, the lower longitudinal bone (4) is installed on the diagonal plate (2) located in the ballast tank area below the main deck (1) after bending, and the upper longitudinal bone (5) is installed on the diagonal plate (2) located in the empty tank area above the main deck (1). Step 3, outfitting platform (6) arrangement: An outfitting platform (6) is added between every two strong frames. The outfitting platform (6) includes a platform (61), two legs (63) set at the bottom of the platform (61), railings (62) set on both sides of the platform (61), and steps (64) set in the middle section of the platform (61). The bottom end of one leg (63) is connected to the upper longitudinal bone (5) of the diagonal plate (2), and the bottom end of the other leg (63) is connected to the bent section of the main deck (1). Step 4, Manhole Optimization Arrangement: Based on the arrangement of the outfitting platform (6), the position of the first manhole (7) on the strong frame is raised towards the direction of the inclined dome deck (13) and moved towards the inner side of the ship to obtain the position of the second manhole (8). The manholes are rearranged according to the position of the second manhole (8).

2. The arrangement method for the bent structure of the main deck of an LNG ship according to claim 1, characterized in that, The distance between the first bend line (9) and the longitudinal bone (3) at the end of the main deck (1) is 20 mm.

3. The arrangement method for the bent structure of the main deck of an LNG ship according to claim 1, characterized in that, The main deck (1) has no longitudinal ribs (3) in the bent section, and the longitudinal ribs (3) in the straight section of the main deck (1) are spaced at a distance of c.

4. The arrangement method for the bent structure of the main deck of an LNG ship according to claim 3, characterized in that, In the bending arrangement, the length of the bending section is less than c, and in the transition arrangement, the length of the main deck (1) is 5c.

5. The arrangement method for the bent structure of the main deck of an LNG ship according to claim 1, characterized in that, The spacing between the bones of the lower longitudinal bone (4) is a, and the spacing between the bones of the upper longitudinal bone (5) is b, and a < b.

6. The arrangement method for the bent structure of the main deck of an LNG ship according to claim 1, characterized in that, With the straight section of the main deck (1) as the X-axis and the direction perpendicular to the straight section of the main deck (1) as the Y-axis, the difference in the vertical coordinate between the coordinates of the center point of the platform (61) and the coordinates of the point on the straight section of the main deck (1) is 300-400mm, and the difference in the horizontal coordinate between the coordinates of the center point of the platform (61) and the coordinates of the center point of the first manhole (7) is 200-300mm.

7. The arrangement method for the bent structure of the main deck of an LNG ship according to claim 6, characterized in that, The difference in the longitudinal coordinates between the center point of the second manhole (8) and the center point of the first manhole (7) is consistent with the difference in the longitudinal coordinates between the center point of the platform (61) and the point on the straight section of the main deck (1); the abscissa of the center point of the second manhole (8) is consistent with the abscissa of the center point of the platform (61).

8. The arrangement method for the bent structure of the main deck of an LNG ship according to claim 1, characterized in that, The second manhole (8) is oval in shape.

9. The arrangement method for the bent structure of the main deck of an LNG ship according to claim 1, characterized in that, The watertight patch is removed from the position of the longitudinal bone through hole of the oblique side plate (2) on the strong frame, and a ground patch (12) is installed.

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