Method for setting an inner shell corner line
By optimizing the setting method of the inner hull corner line, the problems of ship structural fatigue and insufficient space utilization caused by improper design of the inner hull corner line were solved, thereby improving safety, strength and operational efficiency, meeting international standards and increasing loading capacity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DALIAN SHIPBUILDING INDUSTRY CO LTD
- Filing Date
- 2025-09-29
- Publication Date
- 2026-07-24
Smart Images
Figure CN121247005B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of shipbuilding and design, and specifically relates to a method for setting the inner hull corner line. Background Technology
[0002] The hull bend line is a key element in the structural design of double-hull oil tankers, directly affecting the ship's safety, structural strength, construction process, and operational efficiency.
[0003] The inner hull bend line is the transition area between the longitudinal bulkhead and the bottom or top side compartments, bearing the responsibility of transferring longitudinal and lateral loads. During ship navigation, the hull is subjected to various loads such as wave impact, cargo pressure, and mechanical vibration. A well-designed bend line can effectively disperse stress and prevent localized stress concentration that could lead to steel plate cracking or deformation. Improper bend line design may result in structural fatigue or even catastrophic accidents.
[0004] The geometry of the corner lines directly affects the usable space in the cargo hold. A well-designed corner line (such as using rounded transitions or sloping corners) can maximize cargo hold volume and increase cargo capacity. At the same time, smooth corner lines help reduce cargo residue, facilitate cleaning and maintenance, and meet the MARPOL Convention requirements for the cleanliness of oil tanker cargo holds.
[0005] Due to the complex stress variations in the corner area and its long-term exposure to alternating loads, its design directly affects the fatigue life of a ship. The design of the corner must also consider construction processes, such as the feasibility of cold or hot bending. A suitable corner shape can reduce processing difficulty and improve construction efficiency. Simultaneously, the corner area typically includes a maintenance access channel (width ≥ 600mm) to facilitate daily inspection and maintenance, meeting the inspection requirements of classification societies (such as DNV and ABS).
[0006] The hull bend line must meet international standards such as the IMO MARPOL Convention and IACS CSR (Common Structural Standard) to ensure the environmental compliance of the vessel. For example, the bend line position of a double-hull oil tanker must meet the minimum double-hull distance requirement (e.g., ≥2m) to prevent oil tank leaks from polluting the marine environment.
[0007] Therefore, the design of the angle line is a crucial aspect that cannot be ignored in marine engineering. Currently, there is no method for designing the angle line of the inner hull. Summary of the Invention
[0008] To address the aforementioned problems, this invention provides a method for setting inner shell corner lines, aiming to maximize cabin capacity through the rational setting of corner lines. The technical solution adopted is as follows:
[0009] A method for setting the inner shell corner line, the specific steps of which are as follows:
[0010] S1: Draw the initial frame of the ship according to the design requirements. Determine the double bottom height as L1 and the double hull width as L2 according to the total ballast water volume. Offset the lower inflection point downward by 2m to form the inner bottom limit line point M1, and offset the upper inflection point outward by 2m to form the inner hull limit line point M2.
[0011] S2. Import all the hull lines in the parallel midbody area of the ship into the initial frame one by one according to the rib number. The ship's hull lines become thinner from the middle to both ends. Stop when the hull lines imported towards the bow or the hull lines imported towards the stern intersect with the restriction line point M1 or M2. Define the hull lines that intersect with the restriction line M1 towards the bow as FRs, and define the hull lines that intersect with the restriction line M2 towards the stern as FRw.
[0012] S3, import the FRs profile towards the bow into the initial frame one by one according to the rib number. At this time, the inner shell inclined plate will shrink inward at an angle R according to the profile. The FRsn profile will be offset inward by 2000mm. The offset line FRsn' intersects with the ship's inner bottom at point Psn1. The offset line FRsn' intersects with the inner shell at point Psn2. The intersection points Psn1 and Psn2 form a new inner shell inclined plate 2frn. When the intersection point Psn2 is determined to be the minimum point between the profile and the new inner shell inclined plate, draw a perpendicular line vertically upward through Psn2 to form a new inner shell 4frn.
[0013] When the profile contracts inward and the intersection point Psn2 is not the minimum point, a vertical line is drawn downward from the minimum point Psn3 as the base point to intersect with the inclined plate of the inner shell to form a new inner shell bend line.
[0014] Among them, FRsn is the rib line with the number n in the bow section of FRs.
[0015] S4, gradually completing all the hull lines from the cargo hold area to the bow, then ends.
[0016] S5, import the FRw profile towards the stern into the initial frame one by one according to the rib number. At this time, the lower sloping plate will shrink inward at an angle R according to the profile. The FRwn rib profile will be offset inward by 2000mm to form the offset line FRwn'. The offset line FRwn' intersects with the ship's inner bottom at point Pwn1. The offset line FRwn' intersects with the ship's inner hull at point Pwn2. The line connecting Pwn1 and Pwn2 forms a new inner hull sloping plate. When this intersection point is determined to be the minimum point between the profile and the lower sloping plate, draw a vertical line upward through Pwn2 to form a new inner hull 4frn.
[0017] When the profile contracts inward and the intersection point Pwn2 is not the minimum point, a vertical line is drawn downward from the minimum point Pwn3 as the base point to intersect with the inclined plate of the inner shell to form a new inner shell bend line.
[0018] Among them, FRwn is the rib line with the number n in the stern section of FRw.
[0019] S6. In order to increase the cargo hold capacity, when the stern profile gradually flattens out, Pwn1 is tilted upward to form Pwn2 with the inner shell. The straight line formed by Pwn1 and Pwn2 is far from the profile offset line FRwn'. At this time, a downward tilting line can be drawn from the intersection point Pwn2' of the inner shell and the profile offset line to shorten the distance between the offset line and the new inner shell line, forming the intersection point Pwn4 with the inner shell. At this time, the distance between Pwn4 and the outer plate is less than 2m, maximizing the cargo hold capacity while meeting the specifications.
[0020] Furthermore, in the above-mentioned method for setting the inner shell corner line, a box is placed at the intersection of the inclined inner shell plate and the inner bottom. The height of the box is M3 and the width is M4. The width M4 is the intersection of the parallel line determined by M3 and the inclined inner shell.
[0021] Furthermore, in the above-mentioned method for setting the inner shell corner line, the inner shell corner line drawn by the profile between FRs and FRw is consistent with the initial inner shell line.
[0022] Furthermore, the aforementioned method for setting the inner shell corner line can be further improved to 1600mm. <M3<3000mm。
[0023] Furthermore, in the aforementioned method of setting the inner shell corner line, the small box extends continuously along the length of the ship and is equipped with internal reinforcing ribs.
[0024] Furthermore, in the aforementioned method of setting the inner shell corner line, both the double bottom height L1 and the double shell width L2 are greater than 2 meters.
[0025] Furthermore, in the aforementioned method for setting the inner shell corner line, Psn3 is the limiting point for the FRsn type line to offset inward by 2m, and the only limiting point that meets the 2m requirement.
[0026] This invention can coordinate the hull angle lines of the entire ship according to the hull profile, improving the overall safety, economy, and environmental friendliness of the vessel. By optimizing the geometry, strengthening the structural strength, and employing advanced manufacturing processes, the overall performance of the ship can be significantly improved, ensuring its long-term reliable operation in complex sea conditions. It simplifies the construction process, meets strength requirements while reducing structural weight, and increases the overall loading capacity of the ship. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of the shell bend line within the parallel midbody area of the cargo hold;
[0028] Figure 2 Schematic diagram of the hull bend line within the bow cargo hold area;
[0029] Figure 3 Schematic diagram of the hull bend line in the foremost cargo hold area;
[0030] Figure 4 Schematic diagram of the angled line of the inner hull of the stern cargo hold;
[0031] Figure 5 Schematic diagram of the fold line of the inner hull of the stern cargo hold (with small box);
[0032] Wherein, 1-hull outer plating, 2-inner hull inclined plate, 3-side outer plating, 4-inner hull, 6-inner bottom plate, L1-double bottom height, L2-double hull width, M1-inner bottom limiting point, M2-inner hull limiting point, R-inner hull inclined plate angle. Detailed Implementation
[0033] The invention will be further described with reference to the accompanying drawings.
[0034] A method for setting the inner shell corner line, the specific steps of which are as follows:
[0035] S1, based on ship design requirements and the total ballast water volume, determine the double bottom height as L1, the double hull width as L2, and the lower ramp inclination angle as R. Draw the initial border, as follows: Figure 1 As shown. The lower inflection point is offset downwards by 2m to form the inner bottom limiting line M1, and the upper inflection point is offset outwards by 2m to form the inner shell limiting line point M2. This is to meet the requirements of the IMO MARPOL Convention. Figure 1 As shown.
[0036] S2 imports all the hull lines in the parallel midbody region of the ship into the initial border one by one according to the rib number. The ship's hull lines become thinner from the middle to both ends. The process stops when the hull lines imported towards the bow and stern intersect with the restriction lines M1 or M2, defined as FRs and FRw. The inner hull bend lines drawn by the hull lines within the middle range of these intersecting hull lines are consistent with the initial inner hull lines. For example... Figure 2 As shown.
[0037] S3, as Figure 3 As shown, the FRs profile towards the bow is imported into the initial frame one by one according to the rib number. At this time, the lower sloping plate will shrink inward at an angle R according to the profile. The FRsn rib profile is offset inward by 2000mm. The offset line FRsn' intersects with the ship's inner bottom at point Psn1. The new inner shell sloping plate 2frn intersects with the offset line FRsn' at point Psn2. When this intersection point is determined to be the minimum point between the profile and the lower sloping plate, a vertical line is drawn vertically upward through Psn2 to form a new inner shell 4frn. When the profile shrinks inward and the intersection point Psn2 is not the minimum point, a vertical line is drawn downward from the minimum point Psn3 as the base point to intersect with the inner shell sloping plate to form a new bend line.
[0038] S4, gradually completing all the shaped lines from the cargo hold area to the bow, then ends.
[0039] S5, such as Figure 4As shown, the FRw profile towards the stern is imported into the initial frame one by one according to the rib number. At this time, the lower sloping plate will shrink inward at an angle R according to the profile. The FRwn rib profile is offset inward by 2000mm to form the offset line FRwn'. The offset line FRwn' intersects with the ship's inner bottom at point Pwn1. From Pwn1 upward, it intersects with the new inner shell sloping plate 2frn and the offset line FRwn' at point Pwn2. When this intersection point is determined to be the minimum point between the profile and the lower sloping plate, a perpendicular line is drawn vertically upward through Pwn2 to form the new inner shell 4frn. When the profile shrinks inward and the intersection point Pwn2 is not the minimum point, a vertical line is drawn downward from the minimum point Pwn3 as the base point to intersect with the inner shell sloping plate to form a new bend line.
[0040] S6, such as Figure 5 As shown, to increase the cargo hold capacity, when the stern profile gradually flattens, Pwn1 is tilted upwards to form Pwn2 with the inner shell. Since the straight line formed by Pwn1 and Pwn2 is far from the offset line, a downward tilting line can be drawn from the intersection point Pwn2' of the inner shell and the offset line to shorten the distance between the offset line and the new inner shell line, forming intersection point Pwn4 with the inner shell. At this point, the distance between Pwn4 and the outer panel is less than 2m. To meet the requirements of the IMO MARPOL Convention and simultaneously increase the cargo hold capacity, a small box with a height of M3 and a width of M4 (1600mm) can be installed between the inclined inner shell plate and the inner bottom.
Claims
1. A method for setting the corner line of an inner shell, characterized in that, The specific setup steps are as follows: S1: Draw the initial frame of the ship according to the design requirements. Determine the double bottom height as L1 and the double hull width as L2 according to the total ballast water volume. Offset the lower inflection point downward by 2m to form the inner bottom limit line point M1, and offset the upper inflection point outward by 2m to form the inner hull limit line point M2. S2, import all the hull lines in the parallel midbody area of the ship into the initial frame one by one according to the rib number. The ship's hull lines become thinner from the middle to both ends. Stop when the hull lines imported towards the bow or the hull lines imported towards the stern intersect with the restriction line point M1 or M2. Define the hull lines that intersect with the restriction line point M1 towards the bow as FRs, and define the hull lines that intersect with the restriction line point M2 towards the stern as FRw. S3, import the FRs profile towards the bow into the initial frame one by one according to the rib number. At this time, the inner shell inclined plate will shrink inward at an angle R according to the profile. The FRsn profile will be offset inward by 2000mm. The offset line FRsn' intersects with the inner bottom of the ship at point Psn1. The offset line FRsn' intersects with the inner shell at point Psn2. The intersection points Psn1 and Psn2 form a new inner shell inclined plate 2frn. When the intersection point Psn2 is determined to be the minimum point between the profile and the new inner shell inclined plate, draw a perpendicular line vertically upward through Psn2 to form a new inner shell 4frn. When the profile contracts inward and the intersection point Psn2 is not the minimum point, a vertical line is drawn downward from the minimum point Psn3 as the base point to intersect with the inclined plate of the inner shell to form a new inner shell bend line. Wherein, FRsn is the profile line with FRs numbered n towards the bow rib; S4, the process ends after gradually completing all the hull lines from the cargo hold area to the bow; S5, import the FRw profile towards the stern into the initial frame one by one according to the rib number. At this time, the inner shell inclined plate will shrink inward at an angle R according to the profile. The FRwn rib profile will be offset inward by 2000mm to form the offset line FRwn'. The offset line FRwn' intersects with the ship's inner bottom at point Pwn1. The offset line FRwn' intersects with the ship's inner shell at point Pwn2. The line connecting Pwn1 and Pwn2 forms a new inner shell inclined plate. When this intersection point is determined to be the minimum point between the profile and the new inner shell inclined plate, draw a perpendicular line vertically upward through Pwn2 to form a new inner shell 4frn. When the profile contracts inward and the intersection point Pwn2 is not the minimum point, a vertical line is drawn downward from the minimum point Pwn3 as the base point to intersect with the inclined plate of the inner shell to form a new inner shell bend line. Among them, FRwn is the rib line with the number n in the stern direction of FRw; S6. In order to increase the cargo hold capacity, when the stern profile gradually flattens out, Pwn1 is tilted upward to form Pwn2 with the inner shell. The straight line formed by Pwn1 and Pwn2 is far from the profile offset line. At this time, the intersection point Pwn2' of the inner shell and the profile offset line can be tilted downward to shorten the distance between the offset line and the new inner shell line, forming the intersection point Pwn4 with the inner shell. At this time, the distance between Pwn4 and the outer plate is less than 2m.
2. The method for setting the inner shell corner line according to claim 1, characterized in that, A box is provided at the intersection of the inclined plate of the inner shell and the inner bottom. The height of the box is M3 and the width is M4.
3. The method for setting the inner shell corner line according to claim 1, characterized in that, The inner shell bend line drawn by the profile between FRs and FRw is consistent with the initial inner shell line.
4. The method for setting the inner shell corner line according to claim 2, characterized in that, 1600mm <M3<3000mm。 5. The method for setting the inner shell corner line according to claim 2, characterized in that, The box extends continuously along the length of the ship and is reinforced with internal ribs.
6. The method for setting the inner shell corner line according to claim 1, characterized in that, The height L1 of the double bottom and the width L2 of the double shell are both greater than 2 meters.
7. The method for setting the inner shell corner line according to claim 1, characterized in that, Psn3 is the limiting point for the FRsn type line offset inward by 2m.