ES2601160T3 - Underwater vehicle structure such as a submarine - Google Patents

Abstract

Structure of an underwater vehicle, of the type consisting of a thick hull (1) that appears at least over part of its length, in the general form of a cylinder, characterized in that the lateral flanks of this structure (1) consist of al minus a part of the length of the cylinder, of means that form an acoustic baffle (2) consisting of each side of the thick hull, of preparation organs (2) of V section, inclined against the hull (1) and associated to this helmet through shock absorbing and noise damping means (6).

Description

DESCRIPTION

Underwater vehicle structure such as a submarine.

[0001] The present invention relates to an underwater vehicle structure such as a submarine

Properly said.

[0002] More particularly, the invention relates to an underwater vehicle structure consisting of a thick hull that is presented at least over a part of its length in the general form of a cylinder.

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[0003] This structure may also consist of other parts such as, for example, a part called a sail or even a part called an apparatus for directing the submarine.

[0004] Different studies have shown the importance it represented for these structures 15 and, in particular, for submarines, the threat linked to evolutions and the proliferation of sonars such as,

for example, sonars called assets.

[0005] In order to take this threat into account, studies have been carried out to reduce the target Index, that is, to increase in fact the acoustic stealth technology of a submarine, even at a very frequent frequency.

20 low.

[0006] The improvement of the particular acoustic stealth technology of a submarine can be obtained mainly in two ways. In fact, it is about eliminating or canceling the echo sonar forwarded by the target such as, for example, the submarine, towards the threat, that is, the adverse active sound.

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[0007] Thus, the improvement of the stealth technology of a submarine can be obtained by tilting the different flat walls of its structure with respect to the vertical, the sound wave emitted by the adverse sonar is then reflected towards strongly positive or strongly positive sites negative

30 [0008] The threat is, in most cases, to places between more or less

10 °, that is, at a level close to that of the submarine.

[0009] In addition, if the submarine consists of a semi-transparent thin hull placed around a thick hull, the sonar wave is transmitted weakly, which allows hiding the eventual echoes forwarded by the

35 structure and various equipment placed for example under the thin hull of this.

[0010] The improvement of the stealth technology can also be obtained by using on the structure, absorbent acoustic coatings that allow to reduce strongly the amplitude of the wave reflected by the thick hull of the submarine.

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[0011] These absorbent acoustic coatings are also referred to as anechoic coatings.

[0012] FR 2 732 806 A1 describes such acoustic coating.

[0013] The target Index of a submarine is generally maximum on the side, that is, for some

markings at more or less 90 °, due to the echo forwarded by the cylindrical part of the hull and to a lesser extent, by the sail and the device to be directed from it.

[0014] As indicated above, the candle and the apparatus to be directed can be treated by one or the other of the methods described and the cylindrical hull can be treated by an anechoic coating for

improve the submarine's discretion as much as possible.

[0015] However, important difficulties appear at low and very low frequency.

[0016] Indeed, either the anechoic coating is very thick or inefficient.

[0017] In practice, it is difficult to obtain anything better than 6 dB below 3 kHz and anecoism below

1.5 kHz is almost impossible.

[0018] On the other hand, the use of this type of coating is also a problem linked to the implantation of large flank antennas for passive sonar detection.

[0019] Indeed, there is a conflict between this use of large antennas and the implantation of anechoic coating on certain portions of the cylindrical hull.

[0020] It is known, for example, that some submarine manufacturers have proposed to implant flank antennas on anechoic coatings.

10 [0021] However, this has several drawbacks:

- The anechoic coating, even in thick layer, has mediocre yields in very low frequency. In addition, the important compressibility of this coating as a function of hydrostatic pressure is detrimental to naval architecture balances.

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- The presence of this type of coating under a flank antenna degrades its performance at low frequency. In fact, there is no hard reflector behind the sensors of this antenna and acoustic interference appears due to reflections on the hull behind the anechoic lining.

20 [0022] Other submarine manufacturers have proposed using acoustic appendices added in

particular on the cylindrical part of the thick hull of the submarine.

[0023] However, all these solutions are not entirely satisfactory since it is difficult to guarantee at the same time a good acoustic stealth technology of the submarine on the side, allow a good integration of large

25 sonar flank antennas and ensure protection against the side shocks of the thick helmet.

[0024] The aim of the invention is therefore to solve these problems.

[0025] For this purpose, the invention has as its object an underwater vehicle structure according to 30 revindication 1.

[0026] According to other characteristics, the structure according to the invention of a submarine vehicle is in accordance with one or more of claims 2 to 8.

[0027] The invention will be better understood by reading the description given below.

Only by way of example and made in reference to the accompanying drawings in which:

- Figure 1 represents a partial view of a section of generally cylindrical thick hull of an underwater vehicle according to the invention and on a flank of which an acoustic deflector is installed; Y

40 - Figures 2 and 3 represent partial views illustrating variants of realization of this deflector.

[0028] Ace! As illustrated in these figures, the invention relates to an underwater vehicle structure such

as, especially, a submarine proper.

[0029] A submarine generally consists of a thick hull that is presented on at least one part

of its length, in the general form of a cylinder, this part of the thick hull being designated by the general reference 1 in these figures.

[0030] According to the invention, the lateral flanks of this cylindrical part of thick hull are equipped at least a part of their length by 50, by means forming an acoustic deflector, of which one is designated by

general reference 2 in these figures.

[0031] In fact, these means forming an acoustic deflector consist as illustrated in particular in Figures 2 and 3, on each side of the thick hull 1, of the V-section preparation organs, lying against the

55 coarse hull of the submarine and associated with this hull through means of shock and noise damping, of which one end is attached to the preparation organ and the other end is attached to the submarine hull for example.

[0032] In these figures, one of the V-section preparation organs inclined against the helmet

thick, is designated by general reference 3 and consists, for example, of a metal plate with sloping sides on both sides of its central edge, designated by general references 4 and 5.

[0033] This metal plate has for example a thickness between 8 and 10 mm.

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[0034] The sides of the inclined V-plate may be inclined at an angle at least equal to 15 ° with respect to the vertical.

[0035] As indicated above, damping means are provided between these 10 preparation organs and the rest of the helmet.

[0036] These means are designated by the general reference 6 in these figures and consist, for example, of any classical shock absorber structure, for example of a rod, telescopic tubes or other.

[0037] Several dampers are then distributed, for example, along the plate between it and the rest.

of the helmet

[0038] These 6 dampers allow cushioning as! the eventual shocks on the flanks of the thick hull and avoid the transmission of vibrations from the hull to the baffles, which is convenient to reduce

20 of the noise radiated by the submarine and, therefore, at its acoustic discretion.

[0039] Each side of the preparation organ may then be formed by a portion of flat metal material plate such as that designated by general reference 7 in Figure 2.

[0040] An acoustic coating of soft material type, that is of reduced acoustic impedance with a

typical thickness of 20 to 30 mm, is provided for example on the inner side of it. This coating is

designated by general reference 8 in figure 2.

[0041] This configuration then allows the target Index of submarine 30 on the side to be significantly reduced and this at a very low frequency.

[0042] A reduction for example from 10 to 15 dB can be reached at 1.5 kHz.

[0043] In addition and as illustrated in Figure 3, it is also possible to use these preparation organs and,

35 in particular, the lower side 5 of the plate thereof, to install a sonar flank antenna designated by the

general reference 10 in this figure 3.

[0044] This sonar flank antenna then points to the negative sites as shown in this figure.

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[0045] It is known in effect that marking towards negative sites is more favorable in terms of signal / noise ratio.

[0046] The acoustic response of the antenna at low frequencies can also be improved by using additional speakers as known on the other hand.

[0047] In Figure 3, the sonar flank antenna module is designated by the general reference 10 and is therefore installed on the external face of the corresponding lower side 5 of the plate forming the deflector organ, while the internal face of this consists of an additional plate for example of thick steel

50 characteristic of 10 to 20 mm and a layer of soft material of characteristic thickness of 20 to 40 mm.

[0048] This plate and layer assembly then forms an additional speaker designated by general reference 11 in this figure 3, on the inner face of the corresponding side 5 of the plate.

55 [0049] Of course, different ways of carrying out these preparation organs and, in particular, of the

sides or of the flat plates enter into the constitution of these, as well as means that form a shock absorber, can be taken into account.

[0050] Thus, for example, flat parts, ie the sides of this baffle structure, can be

also be made of composite material in order to allow an increase in mass, with the exception of the reception areas of the sonar antennas, in which these sides are necessarily of material of strong acoustic impedance, that is, for example of steel.

[0051] The shape of the acoustic baffle structure can also address the thick hull according to

different configurations connecting to the underwater vehicle bridge or not.

[0052] In addition, the areas between the preparation organs and the thick helmet make it possible to integrate certain small-sized equipment on the outside of this helmet.

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[0053] Similarly, electrical cables can be circulated, for example, for the supply and recovery of the signals of the sonar flank antennas.

[0054] Of course, even other realization modes can be taken into account.

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Claims (6)

1. Underwater vehicle structure, of the type consisting of a thick hull (1) presented to the less on a part of its length, in the general form of a cylinder, characterized in that the lateral flanks 5 of this structure (1) consist of at least a part of the length of the cylinder, of means forming acoustic baffle (2) which consist of each side of the thick helmet, of preparation organs (2) of V section, inclined against the helmet (1) and associated with this helmet through means (6) of shock and noise damping. 10 2. Underwater vehicle structure according to claim 1, characterized in that the organs of Preparation (2) are at least partly metallic. 3. Underwater vehicle structure according to claim 2, characterized in that the preparation organs (2) are made from plates (3) of metallic material. fifteen 4. Underwater vehicle structure according to claim 3, characterized in that the plates (3) consist of inclined sides (4, 5). 5. Underwater vehicle structure according to claim 4, characterized in that the plates (3) 20 have a thickness between 8 and 10 mm. 6. Underwater vehicle structure according to claim 4, characterized in that the inclined sides (4, 5) of the plates (3) are inclined at least 15 ° with respect to the vertical. Structure of submarine vehicle according to any of the preceding claims, characterized because the lower side (5) of the V-section preparation organs (2), consists on its external face, of means that form a flank sonar antenna (10). 8. Underwater vehicle structure according to any of the preceding claims, characterized 30 because the lower side (5) of the V-section preparation organs (2), consists on its internal face, of means forming additional acoustic baffle (11).