A loading method for hydrostatic pressure under damaged condition of a car roll-on / roll-off ship

Abstract

The application discloses a kind of static water pressure loading methods of automobile roll-on / roll-off ship under broken compartment condition, at least including as follows: broken compartment water line is expressed using function segmentation under broken compartment condition at a transverse section;Broken compartment water line is cut into several segments in longitudinal direction under broken compartment condition;The method of finite element is segmented to apply static water pressure under broken compartment condition.The main problem of simulating the correct broken compartment water line under broken compartment condition is solved, so as to accurately check the structural strength of watertight deck;The operation of conventional application method is conservative, which causes the broken compartment pressure to be greater than the actual value, resulting in the unreasonable increase of structure, and the broken compartment water line simulation is accurate in the application, and the structure arrangement is reasonable.

Description

Technical Field

[0001] The present invention relates to the technical field of ships, and in particular to a method for loading hydrostatic pressure under a damaged cabin condition of a roll-on / roll-off car ship. Background Art

[0002] The damage strength of a car roll-on / roll-off ship is crucial to the safety of the hull. Many classification society specifications require verification of the structural strength of the watertight deck under damage conditions.

[0003] In the probabilistic damage stability calculation of a ship, the final equilibrium waterline envelope corresponding to all damage conditions contributing to the survival probability s is derived. This equilibrium waterline envelope reflects the position of the ship's external equilibrium waterline under different damage conditions. Based on the needs of various specialized designs, the damage equilibrium waterline can be further determined at different sections. The damage equilibrium waterline serves as a primary reference for verifying hull structural strength and determining the tightness and height of openings.

[0004] The damaged waterline of a certain cross section of a car ro-ro ship is as follows Figure 1 As shown in the figure, the waterline is not a straight line in the width direction of the ship, but is approximately a multi-segment line. In theory, the hydrostatic pressure exerted by the waterline on the watertight deck at different width positions is different.

[0005] At present, the method for verifying the watertight deck under the damage condition is to take the intersection of a certain cross section and the outer shell as the calculated pressure head (usually the point with the maximum pressure head at the section), calculate the pressure value of the watertight deck at the waterline, and thus solve the structural strength under the damage condition.

[0006] The calculation of damage conditions in the existing technology is very conservative, that is, the calculation results are much worse than the actual situation, resulting in unnecessary strengthening and weight increase of the structure, forming an unreasonable design. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for loading hydrostatic pressure under a damaged cabin condition of a car roll-on / roll-off ship, which mainly solves the problem of correctly simulating the damaged waterline under the damaged cabin condition, thereby accurately checking the structural strength of the watertight deck.

[0008] The object of the present invention is achieved as follows: A method for loading hydrostatic pressure under a damaged cabin condition of a car ro-ro ship comprises at least the following:

[0009] Under the damaged condition, the damaged waterline is expressed by a function segment at a certain cross section;

[0010] Under the damaged condition, the damaged waterline is cut into several segments in the longitudinal direction;

[0011] The finite element method is used to apply the hydrostatic pressure under the damage condition in sections.

[0012] Furthermore, the damage pressure is expressed as:

[0013] P=f1(y), y<a1;

[0014] P=f2(y), a2<y<a1;

[0015] P=f3(y), a3<y<a2;

[0016] …………

[0017] P=f n (y), y>a n ;

[0018] Among them, a1, a2, a3, ..., a n It is the coordinate position of the inflection point of the damaged waterline in the cross section.

[0019] Further, through the function f1 to f n The pressure head of the damaged waterline at a certain cross-section is accurately fitted and then applied to the deck at that cross-section, completing the process of applying the hydrostatic pressure of the damaged condition at a certain cross-section.

[0020] Furthermore, the breach waterline is divided into segments S1-Sn along the length of the ship. The above application process is repeated in each segment to finally obtain the hydrostatic pressure of the watertight deck along the length and width of the ship.

[0021] The beneficial effects of the present invention are:

[0022] 1. Mainly solve the problem of correctly simulating the damaged waterline under damaged conditions, so as to accurately check the structural strength of the watertight deck;

[0023] 2. Conventional application methods are conservative in operation, resulting in a damage pressure greater than the actual value, leading to an unreasonable increase in structure. The present invention accurately simulates the damage waterline under the damage condition and has a reasonable structural layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the damaged waterline under a certain section.

[0025] Figure 2 Schematic diagram of calculation points at different locations.

[0026] Figure 3 It is a schematic diagram of the hydrostatic pressure under the condition of partial damage of a watertight deck.

[0027] In the figure: 1-section waterline; 2-hull; 3-watertight deck. DETAILED DESCRIPTION

[0028] The following is a combination of the embodiments of the present invention Figure 1-3 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] like Figure 1 As shown in the figure, at the calculation points P1, P2, and P3, the calculated pressure heads (vertical distances from the waterline to the calculation points) are theoretically d1, d2, and d3, that is, the calculated pressure heads at different positions in the width direction are variable. Using a uniform d value (d>d1, d2, d3) will cause the calculated pressure to be greater than the actual pressure, resulting in unnecessary structural increases.

[0030] like Figure 2 As shown in the figure, a method for loading the hydrostatic pressure under the damage condition of a car ro-ro ship is proposed. According to the actual pressure head used to apply the damage pressure, the damage pressure can be expressed as:

[0031] P=f1(y), y<a1;

[0032] P=f2(y), a2<y<a1;

[0033] P=f3(y), a3<y<a2;

[0034] …………

[0035] P=f n (y), y>a n ;

[0036] Among them, a1, a2, a3, ..., a n is the coordinate position of the corner point of the damaged waterline in the cross section, such as Figure 2 As shown, Figure 2 The cross-section waterline 1 and the shell 2 can be seen.

[0037] Through the function f1 to f n The pressure head of the damaged waterline (section waterline 1) at a certain cross section is accurately fitted and then applied to the watertight deck 3 at the cross section, completing the application of the hydrostatic pressure of the damaged condition at a certain cross section.

[0038] like Figure 3 As shown in the figure, along the direction of the ship length, the damaged waterline at different sections is not a straight line. A similar method is used to divide the damaged waterline into S1-S2 along the direction of the ship length. n Each section adopts a similar application method as above, and finally obtains the static water pressure of the watertight deck 3 that varies along the length and breadth of the ship.

[0039] The key to this embodiment lies in the segmented description and application method of the damaged waterline under the damaged condition.

[0040] Use the following means:

[0041] Under the damaged condition, the damaged waterline is expressed by a function segment at a certain cross section;

[0042] Under the damaged condition, the damaged waterline is cut into several segments in the longitudinal direction;

[0043] The finite element method is used to apply the hydrostatic pressure under the damage condition in sections.

[0044] Conventional application methods are conservative in operation, resulting in a damage pressure greater than the actual value, leading to an unreasonable increase in structure. In this embodiment, the damage waterline simulation under the damage condition is accurate and the structural arrangement is reasonable.

[0045] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "front", "back", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention; in the present invention, it should also be noted that the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, an integrally formed connection, a mechanical connection, or an indirect connection through an intermediate connecting component, and the specific meaning of the terms in this utility model can be understood according to the specific circumstances.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description. It is intended that all variations within the meaning and range of equivalents of the claims be embraced herein, and any reference signs in the claims should not be construed as limiting the claims to which they relate.

[0047] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for loading hydrostatic pressure under damaged conditions on a ro-ro ship, characterized in that: At least the following: Under the damaged condition, the damaged waterline is expressed by a function segment at a certain cross section; Under the damaged condition, the damaged waterline is cut into several segments in the longitudinal direction; The finite element method is used to apply the hydrostatic pressure under the damage condition in sections; Among them, through the function f1 to f n The pressure head of the damaged waterline at a certain cross section is accurately fitted and then applied to the deck at that cross section, completing the process of applying the hydrostatic pressure of the damaged condition at a certain cross section; Along the length of the ship, the breach waterline is divided into segments S1-Sn in the length direction. The above application process is repeated in each segment to finally obtain the hydrostatic pressure of the watertight deck along the length and width of the ship.

2. The method for applying hydrostatic pressure to a ro-ro ship under a damaged compartment condition according to claim 1, characterized in that: The damage pressure is expressed as: P=f1(y), y<a1; P=f2(y), a2<y<a1; P=f3(y), a3<y<a2; ………… P=f n (y),y>a n ; Among them, a1, a2, a3, ..., a n It is the coordinate position of the inflection point of the damaged waterline in the cross section.

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