Low-radiated-noise ship engine room bottom structure

Abstract

The application discloses a ship engine room bottom structure with low radiation noise. Box body structures are arranged on both sides of the upper part of the ship engine room bottom structure as box body pedestals, a vertical reinforcing plate (14) is arranged in each box body pedestal, the reinforcing plate divides the box body pedestal into two box body structures, and a low-speed main engine (1) is installed based on the box body pedestal. The low-speed main engine installed based on the ship engine room bottom structure of the application has a pedestal foot based on the box body pedestal, so that the vibration generated by the low-speed main engine is transmitted to the lower main body structure through the rigid box body pedestal and then to the bottom, the rigid box body structure can effectively prevent the transmission of low-frequency vibration, thereby effectively reducing the ship body structure vibration and underwater radiation noise caused by the rigidly-installed low-speed main engine.

Description

Technical Field

[0001] This invention relates to a ship noise suppression structure, and more particularly to a ship engine room bottom structure with low radiated noise. Background Technology

[0002] Currently, with the rapid increase in the number and size of commercial ships in recent years, the underwater noise radiated by ships has become increasingly louder. The underwater radiated noise generated by ship navigation will have a certain impact on marine life and damage the marine ecological environment.

[0003] Existing technologies mainly focus on vibration isolation and base structure considerations for medium and high-speed engines, and basically use elastic vibration isolation and damping near the base to solve the problems of vibration and underwater radiated noise. However, for rigidly installed low-speed engines, conventional bottom structure of the engine room is used, without taking into account the problem of underwater radiated noise.

[0004] In summary, the main problem at present is:

[0005] The rigidly installed low-speed two-stroke main engines all use conventional engine room bottom structures, without taking into account the underwater noise radiated by them. This makes it impossible to effectively reduce the hull structure vibration and underwater radiated noise caused by the rigidly installed low-speed two-stroke main engines, thus failing to meet the relevant underwater radiated noise limit requirements.

[0006] In addition, although flat steel with a small height is usually installed at the connection between the main engine mounting bolts and the inner bottom plate for structural reinforcement, this is not enough to achieve sufficient rigidity, and its effect on suppressing hull structural vibration and underwater radiated noise is limited. Summary of the Invention

[0007] The purpose of this invention is to provide a low-radiated-noise bottom structure for a ship's engine room, which can effectively reduce the vibration of the ship's structure and underwater radiated noise caused by a rigidly installed low-speed main engine.

[0008] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0009] A low-radiation noise ship engine room bottom structure, wherein box structures are respectively provided on both sides of the upper part of the ship engine room bottom structure as box bases, and the low-speed main engine is installed on the box bases.

[0010] Furthermore, each box base is provided with an upright reinforcing plate, which divides the box base into two box structures.

[0011] Furthermore, a reinforcing elbow plate is provided between the box base and the main body of the bottom structure of the ship's engine room to strengthen the rigid connection between the box base and the main body of the bottom structure of the ship's engine room.

[0012] Furthermore, an inner bottom plate is provided on the housing base, and the low-speed host is installed based on the inner bottom plate on the housing base.

[0013] Furthermore, damping is installed at the bottom of the ship's engine room structure to reduce underwater radiated noise in the mid- and high-frequency ranges.

[0014] Furthermore, the damping installed at the bottom of the ship's engine room bottom structure adopts either free damping or constrained damping.

[0015] Furthermore, the ship's engine room bottom structure includes an outer bottom plate. Based on the outer bottom plate, above it, there is a central longitudinal girder, two adjacent inner longitudinal girders, and two adjacent outer longitudinal girders. The central longitudinal girder is located at the center of the entire engine room bottom structure. Starting from the central longitudinal girder and extending to the outermost sides of the entire engine room bottom structure, adjacent inner and outer longitudinal girders are sequentially arranged. The two adjacent outer longitudinal girders are located at the outermost sides of the entire engine room bottom structure. The two adjacent inner longitudinal girders are respectively located between the central longitudinal girder and the two adjacent outer longitudinal girders. The ship's engine room bottom structure also includes... The upper platform plate and the lower platform plate are provided. The upper platform plate passes through two adjacent inner longitudinal girder and is located between two adjacent outer longitudinal girder. The lower platform plate is located below the upper platform plate and passes through the central longitudinal girder in the middle and is located between two adjacent inner longitudinal girder. On both sides of the bottom structure of the ship's engine room, the adjacent inner longitudinal girder and the adjacent outer longitudinal girder extend to the upper platform plate. Based on the upper part of the adjacent inner longitudinal girder and the adjacent outer longitudinal girder, an inner bottom plate is provided, thereby forming the box base on both sides of the upper part of the bottom structure of the ship's engine room.

[0016] The main advantages of the low-radiated noise ship engine room bottom structure of the present invention compared with the prior art are as follows:

[0017] Box-shaped bases are installed on both sides of the upper part of the bottom structure of the ship's engine room. The box-shaped bases have strong rigidity. The low-speed main engine installed on the bottom structure of the ship's engine room has its base feet on the box-shaped bases. In this way, the vibration generated by the low-speed main engine must be transmitted to the main structure below through the rigid box-shaped bases, all the way to the bottom. The rigid box-shaped structure can effectively prevent the transmission of low-frequency vibrations, thereby effectively reducing the hull structure vibration and underwater radiated noise caused by the rigidly installed low-speed main engine. Attached Figure Description

[0018] Figure 1 This is a first structural schematic diagram of the low-radiation noise ship engine room bottom structure of the present invention, which is a perspective view;

[0019] Figure 2 This is a second structural schematic diagram of the bottom structure of the ship's engine room according to the present invention, and the diagram is a cross-sectional view;

[0020] Figure 3 This is a schematic diagram of a ship engine room bottom structure using the present invention for installing a low-speed main engine;

[0021] Figure 4 This is a comparison diagram of the underwater radiated sound pressure levels of the ship's engine room bottom structure of the present invention and a conventional bottom structure. Detailed Implementation

[0022] The following provides further details on specific embodiments of the present invention:

[0023] This embodiment provides a low-radiated noise bottom structure for a ship's engine room, which can effectively reduce the vibration of the ship's structure and underwater radiated noise caused by the rigidly installed low-speed main engine 1.

[0024] See Figure 1 Those skilled in the art will understand that a typical ship hull structure is mainly composed of numerous longitudinal girder, platform plate, and rib plate combined together, and then some other components, such as elbow plates, reinforcing plates, etc., are also configured, with an outer bottom plate at the bottom of the hull. The ship engine room bottom structure provided in this embodiment also has this basic structure.

[0025] Specifically, see Figure 1 and Figure 2 In this embodiment, the bottom structure of the ship's engine room is based on the outer bottom plate 5. Above the outer bottom plate 5, there is a central longitudinal girder 11, two adjacent inner longitudinal girder 12, and two adjacent outer longitudinal girder 13. The central longitudinal girder 11 is located in the center of the entire bottom structure of the ship's engine room. Starting from the central longitudinal girder 11, adjacent inner longitudinal girder 12 and adjacent outer longitudinal girder 13 are arranged sequentially on both sides of the bottom structure of the ship's engine room. The two adjacent outer longitudinal girder 13 are located on the outermost sides of the bottom structure of the ship's engine room. The two adjacent inner longitudinal girder 12 are respectively arranged between the central longitudinal girder 11 and the two adjacent outer longitudinal girder 13.

[0026] The ship's engine room bottom structure also includes two platform plates: an upper platform plate 21 and a lower platform plate 22. The upper platform plate 21 is located at a relatively high position in the entire engine room bottom structure. The upper platform plate 21 transversely passes through two adjacent inner longitudinal girder 12 and lies within the area between two adjacent outer longitudinal girder 13. The lower platform plate 22 is located below the upper platform plate 21. The lower platform plate 22 transversely passes through the central longitudinal girder 11 in the center and lies within the area between the two adjacent inner longitudinal girder 12. In other words, the central longitudinal girder 11 and the lower platform plate 22 intersect and are joined together, and this joint is within the area defined by the upper platform plate 21, the outer bottom plate 5, and the two adjacent inner longitudinal girder 12.

[0027] On both sides of the bottom structure of the ship's engine room, the inner longitudinal girder 12 and the outer longitudinal girder 13 extend to the top of the upper platform plate 21. Furthermore, an inner bottom plate 23 is provided on the upper part of the inner longitudinal girder 12 and the outer longitudinal girder 13. Thus, a box structure is formed on both sides of the upper part of the bottom structure of the ship's engine room. For ease of description, this box structure is defined as a "box base" (e.g., Figure 2 (The locations indicated by the middle arrows A1 and A2).

[0028] As for a single box base, it is located on the side of the bottom structure of the entire ship's engine room and above the upper platform plate 21. The upper boundary of the box base is the inner bottom plate 23, the lower boundary of the box base is the upper platform plate 21, and the two side boundaries of the box base are adjacent to the inner longitudinal girder 12 and the outer longitudinal girder 13, respectively.

[0029] In other words, these two box-shaped bases are set up based on the main body of the bottom structure of the ship's engine room, and these two box-shaped bases are located on the upper sides of the bottom structure of the ship's engine room, and protrude upward from the main body of the bottom structure of the ship's engine room.

[0030] See Figure 3 In this embodiment, the low-speed host 1 is installed based on the two aforementioned housing bases, and the base feet of the low-speed host 1 are installed based on the inner bottom plate 23 on the upper part of the housing base.

[0031] The most important innovation of the ship engine room bottom structure in this embodiment is:

[0032] 1) Compared to the existing ship engine room bottom structure, in the ship engine room bottom structure of this embodiment, the upper platform plate 21 extends from the outer longitudinal girder 13 on one side to the outer longitudinal girder 13 on the other side. The upper platform plate 21 is fully spread out on the upper part of the entire ship engine room bottom structure, thereby forming two box bases on the upper parts of both sides of the ship engine room bottom structure. The box bases have strong rigidity. The low-speed main engine 1 installed based on the ship engine room bottom structure has its base feet based on the box bases. In this way, the vibration generated by the low-speed main engine 1 must be transmitted to the main structure below through the rigid box bases, and then to the outer bottom plate 5. That is to say, the vibration needs to pass through multiple box structures before reaching the outer bottom plate 5. These rigid box structures can effectively prevent the transmission of low-frequency vibration, thereby effectively reducing the hull structure vibration and underwater radiated noise caused by the rigidly installed low-speed main engine 1.

[0033] It should be noted that those skilled in the art will understand that the box structure can increase the rigidity of the entire structure, thereby increasing the natural frequency of the structure (increased rigidity leads to increased natural frequency, and the two are positively correlated), thus completely avoiding the excitation frequency of the low-speed main engine, effectively preventing low-frequency vibrations from being transmitted to the structure below the machine, and thus reducing the underwater noise radiated by the entire bottom deck plate (mainly the part in contact with water).

[0034] In addition, the ship engine room bottom structure of this embodiment has other advantages, as follows:

[0035] 2) The bottom structure of the ship's engine room in this embodiment can be adjusted as a whole according to the engine room size of different ship types. The modular design facilitates installation and construction.

[0036] In addition, see Figure 2 Unlike traditional main engine mounts with smaller flat steel bars, this embodiment also includes a vertical reinforcing plate 14 in each housing base. This divides each housing base into two housing structures, thus increasing the rigidity of the housing base itself. A reinforcing elbow plate 31 is also provided between each housing base and the upper platform plate 21, thereby strengthening the rigid connection between the housing base and the main structure at the bottom of the ship's engine room. This further enhances the rigidity of the two housing bases, thus helping to prevent the transmission of low-frequency vibrations.

[0037] Preferably, see Figure 2 In this embodiment, damping is also provided on the outer bottom plate 5. Specifically, a damping layer is sprayed onto the inner surface of the outer bottom plate 5, thereby reducing underwater radiated noise in the mid- and high-frequency ranges.

[0038] In this embodiment, the damping layer uses free damping. In other embodiments, free damping or constrained damping can be selected according to actual needs.

[0039] Finally, it should be noted that the central longitudinal girder 11, the inner longitudinal girder 12, the outer longitudinal girder 13, the upper platform plate 21, the lower platform plate 22, the inner bottom plate 23, and the outer bottom plate 5, etc., are all combined with multiple rib plates. This is common knowledge known to those skilled in the art, so it will not be elaborated on in this article.

[0040] Each longitudinal girder and rib firmly connects the inner bottom plate 23, the upper platform plate 21, the lower platform plate 22 and the outer bottom plate 5 together, reducing the propagation of longitudinal waves, transverse waves and bending waves, and ultimately reducing the underwater acoustic radiation of bending waves from the outer plate structure.

[0041] See Figure 4 The figure provides a comparison of the underwater radiated sound pressure levels of the ship's engine room bottom structure of the present invention with those of a conventional bottom structure. The horizontal axis represents frequency (10~10kHz) in Hz; the vertical axis represents underwater radiated sound pressure level in dB, with a reference sound pressure level of 1×10⁻⁶. -6 Pa, where one vertical grid span represents 10 dB. As can be seen from the figure, the underwater sound pressure level radiated by the ship's engine room bottom structure using this implementation method is significantly lower than that of a conventional bottom structure, demonstrating a significant noise reduction effect across the entire frequency band.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-radiated noise bottom structure for a ship's engine room, characterized in that: Box structures are provided on both sides of the upper part of the bottom structure of the ship's engine room as box bases, and the low-speed main engine (1) is installed based on the box bases.

2. The low-radiated noise ship engine room bottom structure according to claim 1, characterized in that: An upright reinforcing plate (14) is provided in each box base, which divides the box base into two box structures.

3. The low-radiated noise ship engine room bottom structure according to claim 1, characterized in that: A reinforcing elbow plate (31) is provided between the box base and the main body of the bottom structure of the ship's engine room to strengthen the rigid connection between the box base and the main body of the bottom structure of the ship's engine room.

4. The low-radiated noise ship engine room bottom structure according to claim 1, characterized in that: An inner bottom plate (23) is provided on the base of the enclosure, and the low-speed host (1) is installed based on the inner bottom plate (23) on the base of the enclosure.

5. The low-radiated noise ship engine room bottom structure according to claim 1, characterized in that: Damping is installed at the bottom of the ship's engine room structure to reduce underwater radiated noise in the mid- and high-frequency ranges.

6. The low-radiated noise ship engine room bottom structure according to claim 5, characterized in that: The damping installed at the bottom of the ship's engine room bottom structure is either free damping or constrained damping.

7. The low-radiated noise ship engine room bottom structure according to claim 1, characterized in that: The bottom structure of the ship's engine room includes an outer bottom plate (5). Based on the outer bottom plate (5), above the outer bottom plate (5), there is a central longitudinal girder (11), two inner longitudinal girder (12) and two outer longitudinal girder (13). The central longitudinal girder (11) is located in the center of the bottom structure of the entire ship's engine room. Starting from the central longitudinal girder (11), the inner longitudinal girder (12) and the outer longitudinal girder (13) are arranged sequentially on both sides of the bottom structure of the entire ship's engine room. The two outer longitudinal girder (13) are located on the outermost side of the bottom structure of the entire ship's engine room. The two inner longitudinal girder (12) are respectively located between the central longitudinal girder (11) and the two outer longitudinal girder (13). The bottom structure of the ship's engine room is also provided with an upper platform plate (21) and a lower platform plate (22). The upper platform plate (21) passes through two adjacent inner longitudinal girder (12) and is located between two adjacent outer longitudinal girder (13). The lower platform plate (22) is located below the upper platform plate (21). The lower platform plate (22) passes through the central longitudinal girder (11) in the middle and is located between two adjacent inner longitudinal girder (12). On both sides of the bottom structure of the ship's engine room, the inner longitudinal girder (12) and the outer longitudinal girder (13) extend to the top of the upper platform plate (21), and an inner bottom plate (23) is provided on the upper part of the inner longitudinal girder (12) and the outer longitudinal girder (13), thereby forming the box base on both sides of the upper part of the bottom structure of the ship's engine room.

Images