AU2013220310B2

AU2013220310B2 - Submarine structure comprising a sound baffle, for the integration of a sonar receiving antenna on a thin shell

Info

Publication number: AU2013220310B2
Application number: AU2013220310A
Authority: AU
Inventors: Christian Audoly; Francois Reynard
Original assignee: DCNS SA
Current assignee: Naval Group SA
Priority date: 2012-02-17
Filing date: 2013-02-15
Publication date: 2016-09-29
Anticipated expiration: 2033-02-15
Also published as: MY167419A; IN2014DN06560A; ES2581289T3; CA2864412C; AU2013220310A1; EP2814723A1; EP2814723B1; FR2987028A1; PL2814723T3; BR112014020278A8; BR112014020278A2; FR2987028B1; WO2013121007A1; BR112014020278B1; CA2864412A1

Abstract

The invention relates to a submarine structure (1) comprising a thick inner shell (2) and a thin outer shell (3), with sonar receiving antenna means being placed on the sides of said structure. The structure is characterised in that the sonar receiving antenna means comprise receiver means (4) secured to the outer surface of the thin shell (3) and sound baffle means (5) secured to the inner surface of the thin shell (3) opposite the receiver means (4).

Description

Submarine structure comprising a sound baffle, for the integration of a sonar receiving antenna on a thin shell

The present invention relates to a submarine structure comprising a sound baffle, for the integration of a sonar receiving antenna on a thin shell.

More particularly, the invention relates to a submarine structure that includes a thick inner shell, called "strong" shell, and a thin outer shell, with sonar receiving antenna means being placed on the sides thereof.

Submarine structures equipped with this type of antenna are already known from the state of the art.

Thus, reference may for example be made to document FR 2,720,590, in particular to figure 1 of that document, which describes an acoustic side antenna for submarines.

The acoustic antenna is placed on the thick shell of a submarine and comes into contact with the water by means of openings formed in the thin shell of that submarine.

The sensors of the antenna are fastened to the surface of a metal plate forming a hard reflector, and become flush with the thin shell. Absorbing reflectors of the soft type are fastened on the inner surface of the metal plate, and absorbing reflectors made from flexible tubes embedded in a soft matrix are fastened on the outer surface of the thick shell.

The heterogeneity and thickness of such a structure make it complicated to implement, which causes a high manufacturing cost.

Furthermore, the acoustic antenna described in this document is designed to be incorporated on a thick shell, and cannot be incorporated on a thin shell due to its complexity and its thickness.

Preferred embodiments of the invention may resolve these drawbacks and to propose a submarine structure comprising a sound baffle, for the integration of a sonar receiving antenna on a thin shell that has a simple design and is inexpensive to implement.

According to the invention there is provided a submarine structure including a thick inner shell and a thin outer shell, with sonar receiving antenna means being placed on the sides of said structure, wherein the sonar receiving antenna means comprise receiver means secured to the outer surface of the thin shell and sound baffle means secured to the inner surface of the thin shell facing the receiver means.

According to other features of preferred embodiments of the invention, considered alone or in combination: - the sound baffle means include a composite structure comprising at least one plate forming a hard reflector and a sound barrier forming a soft reflector; - stiffeners are positioned on the inner surface of the thin shell, and the sound barrier means are distributed in modules positioned between the stiffeners of the thin shell; - the hard reflector plate is a metal plate; - the hard reflector plate comprises a layer of viscoelastic metal; - the hard reflector plate is fastened on the inner surface of the thin shell and the sound barrier forming the soft reflector is fastened on said plate; - the hard reflector plate has a thickness comprised between 5 and 50 mm; - the soft reflector sound barrier has a thickness comprised between 20 and 100 mm; - the sound baffle means are fastened on the thin outer shell using means for gripping against the latter; - the sound baffle means are fastened on the thin outer shell using gluing means.

The invention will be better understood using the following description, provided solely as an example and done in reference to the appended drawing showing a crosssectional view of a submarine structural part incorporating a sonar receiving antenna according to the invention.

This figure shows a submarine structural part designated by general reference 1.

Traditionally, this submarine structure 1 comprises a thick inner shell designated by general reference 2 and a thin outer shell designated by general reference 3.

According to the invention, the outer surface of the thin outer shell 3 is provided with sonar receiving antenna means. These sonar receiving antenna means comprise receiver means designated by general reference 4.

In the illustrated example, the receiver means 4 include antenna modules distributed along the outer surface of the thin shell 3 on the sides of the submarine structure, and in which sound sensors are for example placed traditionally.

As also illustrated, the sonar receiving antenna means include, on the inner surface of the thin shell 3, sound baffle means designated by general reference 5, positioned across from the receiver means 4.

These sound baffle means 5 include a composite structure comprising at least one plate forming a hard reflector, designated by general reference 6, and a sound barrier forming a soft reflector, designated by general reference 7.

Stiffeners, designated by general reference 8, can also be positioned on the inner surface of the thin shell 3.

In the illustrated example, the stiffeners 8 are regularly distributed on said inner surface of the thin shell 3, and the sound barrier means 5 are distributed in modules positioned between the stiffeners 8 of the thin shell 3.

Advantageously, the hard reflector plate 6 is a metal plate.

Preferably, the plate 6 is made from the same material as that making up the thin shell 3.

Generally, any material with a density significantly higher than that of water is suitable to form the plate 6.

The plate 6 may, for example, comprise a layer of viscoelastic metal. This type of structure makes it possible to increase the structural damping of the device, and therefore to reduce the disruptive noise that may limit the performance of the sound baffle means 5.

In the example illustrated in the appended figure, the hard reflector plate 6 is fastened on the inner surface of the thin shell 3, and the sound barrier 7 forming the soft reflector is fastened on the plate 6.

It will be noted that the hard reflector plate 6 has a thickness comprised between 5 and 50 mm.

It will also be noted that the soft reflector sound barrier 7 has a thickness comprised between 20 and 100 mm.

Generally, the thicknesses of the hard reflector plate 6 and the soft reflector sound barrier 7 are determined based on the frequency range for which the performance of the sound baffle means 5 is optimized.

The soft reflector sound barrier 7 is for example made from a material having an acoustic impedance much lower than that of water. In general, the soft reflector sound barrier 7 is made from a material having a strong impedance break with water.

Lastly, the sound baffle means 5 are fastened on the thin outer shell 3 using means for gripping against the latter.

Alternatively, the sound baffle means 5 are fastened on the thin outer shell 3 using gluing means.

One can then see that such a structure makes it possible to resolve the various aforementioned issues.

Indeed, the participation of the thin shell in the thickness of the sound baffle means 5 makes it possible to limit the excess mass to what is strictly necessary relative to the solutions described in the aforementioned prior art.

Furthermore, this structure does not create any external protuberance that could disrupt the hydrodynamics of the submarine.

Lastly, the presence of the sound baffle means 5 makes it possible to provide a correct sound response by the receiver means 4.

Still other embodiments may of course also be considered.

Thus, such a structure could be assembled during the construction of a new submarine or incorporated into a submarine being refurbished, using means for example with screws or other means for gripping it against the thin shell, or using gluing means.

The invention has been described by way of non-limiting example only and many modifications and variations may be made thereto without departing from the spirit and scope of the invention.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOW:

1. A submarine structure including a thick inner shell and a thin outer shell, with sonar receiving antenna means being placed on the sides of said structure, wherein the sonar receiving antenna means comprise receiver means secured to the outer surface of the thin shell and sound baffle means secured to the inner surface of the thin shell facing the receiver means.
2. The structure according to claim 1, wherein the sound baffle means include a composite structure comprising at least one plate forming a hard reflector and a sound barrier forming a soft reflector.
3. The structure according to claim 1 or 2, wherein stiffeners are positioned on the inner surface of the thin shell, and in that the sound barrier means are distributed in modules positioned between the stiffeners of the thin shell.
4. The structure according to claim 2 or 3, wherein the hard reflector plate is a metal plate.
5. The structure according to any one of claims 2 to 4, wherein the hard reflector plate comprises a layer of viscoelastic metal.
6. The structure according to any one of claims 2 to 5, wherein the hard reflector plate is fastened on the inner surface of the thin shell and in that the sound barrier forming the soft reflector is fastened on said plate.
7. The structure according to any one of claims 2 to 6, wherein the hard reflector plate has a thickness comprised between 5 and 50 mm.
8. The structure according to any one of claims 2 to 7, wherein the soft reflector sound barrier has a thickness comprised between 20 and 100 mm.
9. The structure according to any one of the preceding claims, wherein the sound baffle means are fastened on the thin outer shell using means for gripping against the latter.
10. The structure according to any one of claims 1 to 8, wherein the sound baffle means are fastened on the thin outer shell using gluing means.