CZ2021108A3 - Acoustic partition - Google Patents

Abstract

The solution concerns the acoustic partition (1) between the space (4) with the noise source (2) and the space (5) for receiving the noise. The partition (1) is formed by a thin plate with both radii (R1, R2) of curvature of finite size and the same sign. The partition (1) is equipped with at least one rib (10) of closed or open shape. The ribs (10) are formed by thin plates with both radii of curvature of finite size and the same sign. The thickness (td) of the partition (1) is equal to or less than the thickness (tz) of the ribs (10).

Description

Acoustic partition

Field of technology

The invention relates to an acoustic partition between a space with a noise source and a space for receiving noise.

Current state of the art

Today's partitions between spaces where there is a source of noise and spaces where there are people with a need for reduced noise are mainly constructed by choosing different absorbing materials. Their shape is not systematically chosen. In many cases, the external shape of the space is cylindrical, which increases the emission of acoustic energy on surface lines. If the partitions are made of thin plates and are reinforced with ribs, then for manufacturing reasons the ribs have planar transitions, which increases the emission of acoustic energy.

The object of this invention is a device for reducing the transmission of noise through a partition, the construction of which is based on structural elements with less emission of acoustic energy applicable to any material.

The essence of the invention

The essence of the acoustic partition between the space with the noise source and the space for receiving noise according to the invention is that the acoustic partition is formed by a thin plate with both radii of curvature of finite size and the same sign. The acoustic partition is equipped with at least one rib of closed or open shape. Zebras are formed by thin plates with both radii of curvature of finite size and the same sign. The zebras can be oval and arranged next to each other or concentrically, or they are arranged above each other in layers, they can be provided with openings between the spaces of adjacent ribs or the spaces of ribs and additional ribs. The thickness of the acoustic baffle is equal to or less than the thickness of the fins. Inside the ribs and/or additional ribs is a sound-insulating material.

Clarification of drawings

The essence of the acoustic partition between the space with the source of noise and the space for receiving noise is shown schematically in the attached images, where it shows:

Fig. 1 general layout of a noise barrier between two spaces;

Fig. 2 specific partition, or part thereof;

Figs. 3 to 12 of alternative forms of the partition provided with ribs;

Figs. 13a, b to 18a, b are a section and plan view of other alternative forms of the partition equipped with ribs;

Fig. 19 alternative form of the partition with passages between the spaces of the individual ribs;

Fig. 20a, b longitudinal and transverse section of another alternative form of partition with ribs;

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Examples of implementation of the invention

Fig. 1 shows a general typical arrangement of noise (acoustic energy) transmission between two spaces. Noise is also vibrations and shocks (NVH = noise, vibration, harshness) and sound. Space 4 with source 2 of noise is separated by an acoustic partition 1 from space 5 with receiver 3 of noise. The goal of the acoustic partition 1 is to reduce the transmission of noise from space 4 to space 5. An example of a source 2 of noise is, for example, an internal combustion engine in a car or an airplane, and the recipient 3 of noise is a driver or a passenger. Acoustic partition 1 is the dashboard of a car or the fuselage of an airplane. The source 2 of the noise can also be the cylinder of the combustion engine, and the receiver 3 of the noise is the engine compartment of the car, and the acoustic partition 1 is the cover of the engine head.

The acoustic partition solution according to this invention is based on the knowledge that flat surfaces (having infinite radii of curvature) radiate acoustic energy more than curved surfaces (radius of curvature finite) and surfaces containing straight lines (one infinite radius or radii of curvature of different sign) radiate acoustic energy more than areas not containing straight lines (radii of curvature of the same sign). Therefore, cylindrical, conical and straight surfaces are unsuitable. Thin-walled constructions emit less acoustic energy than thick-walled constructions because they are lighter and contain material points (given by the imaginary cut-out of the construction) with less weight. A thin-walled structure can have problems with structural stability and deformation under load, therefore it is equipped with ribs for strengthening.

Fig. 2 shows the solution of the acoustic partition consisting in the fact that the acoustic partition 1 consists of a thin plate with thickness td, whose boundary surface has both main curvatures with radii RI and R2. Curvature of radius R1 and curvature of radius R2 are finite magnitudes of the same sign. Noise transmission is reduced when the acoustic partition 1 is as thin as possible, i.e. the smallest possible thickness td and the acoustic partition 1 is not flat, i.e. it has both curvatures of finite size, and it does not contain straight lines, i.e. both curvatures of the same sign. The acoustic partition 1 is thin when its thickness td is at most 0.1 of the plate dimension (length or width) or 0.1 of the radius R1 or R2. Acoustic partition 1 is a thin "bombed" plate. A plate is a material object between two (exactly or approximately) equidistant surfaces, and the curvature of the plate is the curvature of the boundary surface of the plate.

Fig. 3 shows that the thin plate according to Fig. 1, in order to withstand the thinness in terms of strength and structural stability, must be equipped with rib(s) 10 with a thickness of

Fig. 4 shows an example where the acoustic partition 1 is equipped with two ribs 10.

In Fig. 5 and the other Figs. 6 to 12, different arrangements of different numbers of ribs 10 are schematically shown. In Fig. 5, two rectangular ribs 10. In Fig. 6, several rectangular ribs 10. 8 polygonal ribs 10, in the given case hexagonal, in Fig. 9 oval (elliptical) ribs JO and in Fig. 10 curvilinear ribs 10 as a closed curve, in Fig. 11 curvilinear ribs 10 from several non-closed curves. In Fig. 12, the ribs 10 are oval (elliptical), mutually nested. Since the ribs 10 are also acoustically excited, they can emit noise. Therefore, it is suitable that the ribs 10 are also thin and have both main curvatures of the final magnitude of the same sign.

The ideal solution of the ribs JO is in Fig. 9 and Fig. 12, because the ribs 10 in the projection have a curvature of the same sign. Fig. 13 and 14 show the second curvature of the ribs 10 of the same sign. In the projection on the right in figure 13 and 14, the ribs 10 have a curvature of one sign, and perpendicular to the plate of the acoustic partition 1 in the projection on the left in the figure, they have a curvature of the same sign as in the projection on the right.

Fig. 15 shows the solution of the acoustic partition 1 with the rib 10, which is closed and has curvatures of finite size and the same sign. If the rib 10 is closed, it is structurally more stable and can be thinner. The thinner JO rib emits less acoustic energy.

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Fig. 16 shows the solution of the acoustic partition 1 with ribs 10, which is closed and has curvatures of finite size and the same sign. The zebras 10 cover the whole or a large part of the acoustic partition 1. It is similar to the solution of Fig. 8, but the ribs 10 are closed and have curvatures of finite size and the same sign.

Fig. 17 shows a solution of an acoustic partition 1 with ribs 10 which are covered by additional ribs 12. The additional ribs 12 are connected to the rib(s) 10 or another additional rib(s) 12.

In the given case, the ribs 10 are separately connected to the acoustic partition 1 and the additional ribs 12 are not connected to the acoustic partition 1. The advantage is that the ribs 10 or the additional ribs 12 can be both thin-walled and thus radiate less acoustic energy, and on the other hand form additional partitions to prevent further spread of noise.

Fig. 18 shows a similar solution to the acoustic partition from Fig. 17. The additional ribs 12 here connect the acoustic partition 1 with the rib 10. Only the next layer of additional ribs 12 is connected only to the previous additional ribs 12. Furthermore, inside the closed additional rib 12 there is a filling from acoustic insulation material 6, which can be, for example, foam, cotton wool, loose material, granules, particles. This filling can occur inside other or all or only some of the ribs 10 and/or 12. This filling can fill the entire space of the rib or only a part.

Fig. 19 shows a similar solution from Fig. 18 consisting in the fact that the rib 10 and/or additional ribs 12 contain a different number of holes 13. The holes 13 are next to each other or are separated by the attachment of additional ribs 10 or 12. The advantage is that the openings 13 allow the sound to pass through, but it is attenuated by interaction with the internal space inside another additional rib 12. Inside the ribs 10 or 12, there may also be other open ribs, for example according to Figs. 13 and 14.

Fig. 20 shows the solution of the acoustic partition 1, which is closed, for example the fuselage of the aircraft, the cabin of the crew or, conversely, the engine compartment. Longitudinal and cross-sectional views are shown. Acoustic baffle 1 is thin and has curvatures of finite magnitude and equal sign. The closed acoustic partition 1 in Fig. 20 has a shape significantly different from a cylinder. It can be reinforced with ribs 10 and additional ribs 12. These ribs can cover the entire acoustic partition L

Zebra 10 and 12 represent "insect (bee) comb" patterns in certain embodiments.

The advantage of the described invention is the possibility to reduce the transmission of noise between two spaces through a partition. The essence is to create a thin-walled acoustic partition in the shape of a thin plate with curvatures of finite size and the same sign. The board is as thin as possible and its strength and structural stability is solved by the ribs. Zebras are thin and also have curvatures of finite magnitude and the same sign. The area of each rib 10, 12 is significantly smaller than the area of the acoustic partition 1.

The greater the curvature and the smaller the thickness and the smaller the area, the less radiated acoustic energy will pass through the partition or rib.

Inside the closed ribs 10 or 12, there can be a filling made of acoustically insulating material 6, which can be, for example, foam, cotton wool, loose material, granules, particles. Loose material, which in addition does not completely fill the space of the rib, begins to move under the action of acoustic energy and dampens the acoustic energy by the friction of the particles against each other. An example is sand.

All described variants can be combined with each other in different numbers. The device can be made of any material. A suitable production technology is 3D printing, which allows the creation of ribs with finite curvatures and closed ribs.

Claims (8)

1. An acoustic partition between the space (4) with the noise source (2) and the space (5) for receiving noise, characterized by the fact that the partition (1) is formed by a thin plate with both radii (RI, R2) of curvature of finite size and the same sign . 2. Acoustic partition according to claim 1, characterized in that the partition (1) is provided with at least one rib (10) of closed or open shape. 3. Acoustic partition according to claim 2, characterized in that the ribs (10) and/or additional ribs (12) are formed by thin plates with both radii of curvature of finite size and the same sign. 4. Acoustic partition according to claim 2 and 3, characterized in that the ribs (10) are oval and arranged next to each other or concentrically. 5. Acoustic partition according to claim 2 and 3, characterized in that the ribs (10) and/or additional ribs (12) are arranged one above the other in layers. 6. Acoustic partition according to claim 5, characterized in that the ribs (10) and/or additional ribs (12) are provided with openings (13) connecting the spaces of the closed ribs (10) and/or additional ribs (12). 7. Acoustic partition according to claim 2 and 3, characterized in that the thickness (td) of the partition (1) is equal to or less than the thickness (tz) of the ribs (10). 8. Acoustic partition according to claim 2 and 3, characterized by the fact that inside the ribs (10) and/or additional ribs (12) there is sound insulation material (6).