SOUND WAVES ABSORBING LAMINATE COMPOSITE MATERIAL STRUCTURE

Abstract

A sound wave absorbing laminate composite material structure for an aircraft including stacked plies of a hybrid composite material, wherein each of the hybrid composite material plies includes first polymer material tows parallel to a warp direction, second polymer material tows parallel to a weft direction, and sound absorbent material tows parallel to the warp direction, wherein the first and second polymer material tows carbon or glass fiber reinforcing polymer.

Claims

1. A sound wave absorbing laminate composite material structure for an aircraft comprising: at least three plies of a hybrid composite material, wherein each of the hybrid composite material plies includes: a plurality of first polymer material tows arranged parallel to a warp direction, wherein each of the first polymer material tows has a first width W.sub.1 a plurality of second polymer material tows arranged parallel to a weft direction, wherein each of the second polymer material tows has a third width W.sub.3, a plurality of sound absorbent material tows arranged parallel to the warp direction, wherein each of the sound absorbent material tows has a second width W.sub.2, the first and second polymer material tows are tows of carbon fiber reinforcing polymer (CFRP) or glass fiber reinforcing polymer (GFRP); and the plurality of first polymer material tows, the plurality of second plurality of second polymer material tows, and the plurality of sound absorbent material tows are intertwined in each of the hybrid material plies; and the first width W.sub.1, the second width W.sub.2 and the third with W.sub.3 conform with a formula which is:
<(2W.sub.2+W.sub.1). wherein is a wavelength of a sound wave.

2. The sound wave absorbing laminate composite material structure according to claim 1, further comprising a plurality of composite material plies of carbon fiber reinforcing polymer (CFRP) or glass fiber reinforcing polymer (GFRP), wherein the plurality of composite material plies are between a pair of adjacent ones of the hybrid composite material plies.

3. The sound wave absorbing laminate composite material structure according to claim 1, wherein the first width W.sub.1 is equal to the third width W.sub.3.

4. The sound wave absorbing laminate composite material structure according to claim 1, wherein the plurality of first polymer material tows, the plurality of second plurality of second polymer material tows, and the plurality of sound absorbent material tows are intertwined in a 22 twill weave pattern.

5. The sound wave absorbing laminate composite material structure according to claim 1, wherein the plurality of first polymer material tows, the plurality of second plurality of second polymer material tows, and the plurality of sound absorbent material tows are intertwined in a 5 harness pattern.

6. The sound wave absorbing laminate composite material structure according to claim 1, wherein the at least three stacked hybrid material plies are arranged in a stack and include: a first hybrid composite material ply in which the plurality of first polymer material tows are oriented in a first direction (d.sub.1), a second hybrid composite material ply in which the plurality of first polymer material tows are oriented in a second direction (d.sub.2), and a third hybrid composite material ply in which the plurality of first polymer material tows are oriented in a third direction (d.sub.3), wherein the second direction (d.sub.2) forms +45 angle respect to the first direction (d.sub.1) and the third direction (d.sub.3) forms 45 angle respect to the first direction (d.sub.1).

7. The sound wave absorbing laminate composite material structure according to claim 1, further comprising, in order of stacking on a stack, at least thirty plies of a composite material, a first hybrid composite material ply of the hybrid composite material plies, a second hybrid composite material ply of the hybrid composite material plies, a further ply of composite material, a third hybrid composite material ply of the hybrid composite material plies.

8. The sound wave adsorbing laminate composite material of claim 1, wherein in the first hybrid composite material ply the plurality of first polymer material tows are oriented in a first direction (d.sub.1), the in second hybrid composite material ply the plurality of first polymer material tows are oriented in a second direction (d.sub.2), and the in third hybrid composite material ply the plurality of first polymer material tows are oriented in a third direction (d.sub.3), wherein the first direction (d.sub.1) forms +45 angle respect to the second direction (d.sub.2) and the third direction (d.sub.3) forms +135 angle respect to the second direction (d.sub.2).

9. The sound wave absorbing laminate composite material structure according to claim 1, wherein the sound absorbent material is an insulation material comprising tows of an elastomeric material.

10. The sound wave absorbing laminate composite material structure according to claim 1, wherein the sound absorbent material is a reinforced insulation material comprising tows of an elastomeric material and a reinforcement carrier embedded in the elastomeric material.

11. The sound wave absorbing laminate composite material structure according to claim 10, wherein the reinforcement carrier is a mesh of carbon fiber or glass fiber.

12. A method for manufacturing a sound wave absorbing laminate composite material structure including: forming hybrid composite material plies, wherein each of the hybrid composite material ply is formed by arranging side-by-side first polymer material tows and sound absorbent material tows which are parallel to a warp direction, and interleaving second polymer material tows with the first polymer material tows and the sound absorbent material tows, wherein the second polymer material tows are parallel to a weft direction, stacking into a stack at least three of the hybrid composite material plies, and bonding together the at least three hybrid composite material plies in the stack.

13. The method according to claim 12, wherein the stacking includes: orienting the first polymer material tows in a first hybrid material ply of at least three of the hybrid composite material plies in a first direction, orienting the first polymer material tows in a first hybrid material ply of at least three of the hybrid composite material plies in a second direction, orienting the first polymer material tows in a third hybrid material ply of at least three of the hybrid composite material plies in a third direction, wherein the second direction is oriented at an angle of +45 to the first direction and the third direction is at an angle of 45 angle to the first direction.

14. The method according to claim 13, wherein the stacking includes: orienting the first polymer material tows in a first hybrid material ply of at least three of the hybrid composite material plies in a first direction, orienting the first polymer material tows in a first hybrid material ply of at least three of the hybrid composite material plies in a second direction, orienting the first polymer material tows in a third hybrid material ply of at least three of the hybrid composite material plies in a third direction, wherein the second direction is oriented at an angle of +45 to the first direction and the third direction is at an angle of +135 to the second direction

15. The method according to claim 12, further comprising interspersing a composite material plies between a pair of adjacent ones of the hybrid composite material plies

16. A laminate composite material structure comprising: a stack of plies of a hybrid composite material, wherein each of the hybrid composite material plies includes: first polymer material tows parallel to a warp direction, wherein each of the first polymer material tows has a first average width W.sub.1, second polymer material tows arranged parallel to a weft direction, wherein each of the second polymer material tows has a third average width W.sub.3, sound absorbent material tows arranged parallel to the warp direction, wherein each of the sound absorbent material tows has a second average width W.sub.2, the first and second polymer material tows are tows of carbon fiber reinforcing polymer or glass fiber reinforcing polymer; and the plurality of first polymer material tows, the plurality of second plurality of second polymer material tows, and the plurality of sound absorbent material tows are intertwined in each of the hybrid material plies.

17. The laminate composite material of claim 16, wherein the first width W.sub.1, the second width W.sub.2 and the third with W.sub.3 conform with a formula which is:
<(2W.sub.2+W.sub.1). wherein is a wavelength of a sound wave.

18. The sound wave adsorbing laminate composite material of claim 16, wherein in the first hybrid composite material ply the plurality of first polymer material tows are oriented in a first direction (d.sub.1), the in second hybrid composite material ply the plurality of first polymer material tows are oriented in a second direction (d.sub.2), and the in third hybrid composite material ply the plurality of first polymer material tows are oriented in a third direction (d.sub.3), wherein the first direction (d.sub.1) forms +45 angle respect to the second direction (d.sub.2) and the third direction (d.sub.3) forms +135 angle respect to the second direction (d.sub.2).

Description

DETAILED DESCRIPTION

[0065] FIG. 1 shows a cross sectional view of a sound wave absorbing laminate composite material structure (1) for an aircraft structure. The laminate composite material structure (1) comprises three plies of a hybrid composite material (2) according to a first embodiment of the present invention.

[0066] FIG. 2 shows a cross sectional view of a second embodiment of a sound wave absorbing laminate composite material structure (1) for an aircraft structure. The laminate composite material structure (1) comprises three plies of hybrid composite material (2: 2.1, 2.2, 2.3) and four plies (6) of a carbon fiber reinforcing polymer (CFRP) composite material. The hybrid composite material plies (2) are interspersed between the CFRP plies (6).

[0067] In a particular example, the first hybrid composite material ply (2.1) is arranged in a first direction (d.sub.1), the second hybrid composite material ply (2.2) is arranged in a second direction (d.sub.2), and the third hybrid composite material ply (2.3) is arranged in a third direction (d.sub.3) respectively. The second direction (d.sub.2) forms +45 angle respect to the first direction (d.sub.1) and the third direction (d.sub.3) forms 45 angle respect to the first direction (d.sub.1).

[0068] FIG. 3 shows a cross sectional view of a third embodiment of a sound wave absorbing laminate composite material structure (1) for an aircraft rear structure which protects the auxiliary power unit (APU). The laminate composite material structure (1) comprises from the outside of the aircraft to the inside, thirty plies of composite material (6), a first hybrid composite material ply (2.1), a ply of composite material (6), a second hybrid composite material ply (2.2), a ply of composite material (6), a third hybrid composite material ply (2.3), and three plies of composite material (6). In a particular example, the first hybrid composite material ply (2.1) is arranged in a first direction (d.sub.1), the second hybrid composite material ply (2.2) is arranged in a second direction (d.sub.2), and the third hybrid composite material ply (2.3) is arranged in a third direction (d.sub.3) respectively. The first direction (d.sub.1) forms +45 angle respect to the second direction (d.sub.2) and the third direction (d.sub.3) forms +135 angle respect to the second direction (d.sub.2). The composite material plies (6) are preferably carbon fiber reinforcing polymer (CFRP).

[0069] FIGS. 4 and 5 show hybrid composite material ply (2) that comprises a plurality of first polymer material tows (3) (identified by dots), a plurality of second polymer material tows (4) (identified by crossed lines), and a plurality of sound absorbent material (5). These polymer material tows (3, 4) are plastic material reinforced by carbon fiber or glass fiber. The sound absorbent material (5) may be an elastomeric material. The first polymer material tows (3) are arranged in a warp direction (d.sub.warp) and each first polymer material tow (3) comprises a first width W.sub.1. The second polymer material tows (4) are arranged in a weft direction (d.sub.weft) and each second polymer material tow (4) comprises a third width W.sub.3. The elastomeric material tows (5) are arranged in the warp direction (d.sub.warp) parallel to the first polymer material tows and each elastomeric material tow (5) comprises a second width W.sub.2. In a particular embodiment, the first width W.sub.1 is equal to the third width W.sub.3.

[0070] A tow is a bundle of fibers generally aligned along a common longitudinal direction. A warp direction is oriented in a lengthwise direction of a ply, and a weft direction is generally perpendicular direction to the warp direction. The weft direction typically extends side-to-side of a ply. Tows are arranged

[0071] In FIG. 4, the first (3) and second (4) polymer material tows and the elastomeric material tows (5) are intertwined among them forming a 22 twill weave carbon fiber pattern (8) as it can be observed. A twill is a type of weave pattern in which the second (4) polymer material tows, which are oriented in the weft direction, are intertwined with the first (3) polymer material tows and the elastomeric material tows (5) which are both oriented in the warp direction. In a 22 twill weave each tow (3, 4 5) passes over two tows oriented perpendicular to the two before going under the next twos.

[0072] In FIG. 5, the first (3) and second (4) polymer material tows and the elastomeric material tows (5) are intertwined among them forming a 5 harness carbon fiber pattern (8).

[0073] The acoustic properties of the present laminate composite material structure (1) depend on the width of tows which form each hybrid composite material ply (2) because wave length attenuated depend on said width. Thus, the present laminate composite material structure (1) is suitable for absorbing wave length () at different levels of absorption. For a low wave length absorption, the expression (2W.sub.2+W.sub.1) has to be greater than the wave length (). For an average wave length absorption, the first width W.sub.1 has to be lower than the wave length (). For a high wave length absorption, the expression (2W.sub.2+W.sub.1) has to be greater than the wave length () and the wave length has to be also greater than the first width W.sub.1.

[0074] The present sound wave absorbing laminate composite material structure (1) in addition is capable to transmit shear efforts of the aircraft structure by the tows comprised in each hybrid composite material ply (2).

[0075] The present invention additionally provides a method for manufacturing a sound wave absorbing laminate composite material structure (1), the method comprising the following steps:

[0076] providing at least three plies (2) of hybrid composite material,

[0077] stacking the at least three hybrid composite material plies (2),

[0078] bonding the at least three hybrid composite material plies (2), and

[0079] obtaining the laminate composite material (1);

[0080] wherein each hybrid composite material ply (2) is manufactured by the following steps:

[0081] providing a plurality of first polymer material tows (3) in a warp direction (d.sub.warp),

[0082] providing a plurality of second polymer material tows (4) in a weft direction (d.sub.weft), each second polymer material tow (4) being intertwined with the plurality of first polymer material tows (3),

[0083] providing a plurality of sound absorbent material tows (5) in the warp direction (d.sub.warp), each sound absorbent material tow (5) being intertwined with the first (3) and second (4) polymer material tows,

[0084] wherein in the manufacturing of the hybrid composite material ply, the first polymer material tows (3) and the sound absorbent material tows (5) are respectively prestressed with a first and second stress, and the second polymer material tows (4) are in charge of intertwining with the first polymer material tows (3) and the sound absorbent material tows (5).

[0085] In the steps of manufacture the hybrid composite material ply (2), firstly the first polymer material tows (3) and sound absorbent material tows (5) are arranged respectively prestressed in a warp direction (d.sub.warp) with a first and second stress; secondly the second polymer material tows (4) are intertwined with the first polymer material tows (4) and the sound absorbent material tows (5) in a weft direction (d.sub.weft). In this way, all the tows (3, 4, 5) being intertwined between them.

[0086] In a particular embodiment wherein the laminate composite material structure (1) comprises three hybrid composite material plies (2) (as it is shown in FIGS. 1 or and 2), the stacking of the hybrid composite material plies (2) is performed by the following steps:

[0087] stacking a first hybrid material ply (2.1) in a first direction (d.sub.1),

[0088] stacking a second hybrid material ply (2.2) in a second direction (d.sub.2) forming +45 angle respect to the first direction (d.sub.1),

[0089] stacking a second hybrid material ply (2.3) in a third direction (d.sub.3) forming 45 angle respect to the first direction (d.sub.1).

[0090] FIG. 6 shows an exploded view of an embodiment of stacking three hybrid composite material plies (2: 2.1, 2.2, 2.3) for a laminate composite material structure (1). In this figure, it can be identified the orientation of each ply (2.1, 2.2, 2.3) according to this particular embodiment. The first hybrid composite material ply (2.1) is oriented in the laminate composite material in a first direction (d.sub.1). The second hybrid composite material ply (2.2) is oriented in the laminate composite material in a second direction (d.sub.2) which forms +45 angle respect the first direction (d.sub.1). The third hybrid composite material ply (2.3) is oriented in the laminate composite material in a third direction (d.sub.3) which forms 45 angle respect the first direction (d.sub.1).

[0091] The three hybrid composite material plies (2.1, 2.2, 2.3) shown in FIG. 6 comprises a patterns according to the example shown in FIG. 4.

[0092] FIG. 7 shows an aircraft (7) comprising an aircraft structure (not shown) manufactured with a sound wave absorbing laminate composite material structure (1). In a particular embodiment, the aircraft structure is a fan cowl. In another particular embodiment, the aircraft structure is the passenger's cabin. In another particular embodiment, the aircraft structure is a tail cone or a rear section of the aircraft.

[0093] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.