CN112992113B - Light and thin composite sound insulation structure based on acoustic super-surface and sound insulation method - Google Patents
Light and thin composite sound insulation structure based on acoustic super-surface and sound insulation method Download PDFInfo
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- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
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Abstract
The invention provides a light and thin composite sound insulation structure and a sound insulation method based on an acoustic super-surface, wherein the light and thin composite sound insulation structure based on the acoustic super-surface comprises the following components: the sound source side surface sound insulation layer, the middle sound insulation layer and the sound insulation side surface sound insulation layer are arranged on the sound source side surface; a plurality of first convex grooves are arranged on the reverse side of the sound insulation layer on the side surface of the sound source; the front surface of the middle sound insulation layer is provided with a plurality of grooves; the upper sub-space forms an upper sound absorbing layer for arranging the gradient foam units. The lower subspace forms a lower vibration-damping sound-absorbing layer for arranging vibration-damping sound-absorbing materials. The invention has the advantages of simple structure, easy processing, splicing and assembly, low cost, high structural strength and rigidity, small density, thin thickness, fire prevention and heat preservation, wide frequency band sound insulation effect, excellent blocking effect on low-frequency band noise, realization of higher sound insulation on specific frequency band noise by matching with the sub-wavelength acoustic super-surface design in the sound absorption layer and the application of damping materials, and good application prospect.
Description
Technical Field
The invention relates to the technical field of sound insulation and noise reduction, in particular to a light and thin composite sound insulation structure based on an acoustic super-surface and a sound insulation method.
Background
The rapid development of modern society leads to the gradual appearance of environmental pollution problems. Noise pollution is one of the environmental pollution, and causes great harm to the production and life of human beings. Among them, the noise problem in aerospace, transportation and industrial production is particularly serious. In the field of aviation, engine noise and noise generated by friction between an aircraft body and air in the high-speed flight process of an aircraft are very huge, and commercial aircraft pay attention to the noise level and riding comfort of a passenger cabin, so that a sound insulation wall plate needs to be installed on the inner wall of the aircraft to isolate the noise, and the weight, thickness and heat insulation performance of the sound insulation wall plate are strictly limited; in industrial production, the noise sound pressure level of mechanical equipment in the working process is generally higher than 90dB, and serious harm is brought to the use comfort level and physical and psychological health of operators, so that the sound insulation cover is very wide in application, and the occupied area and the thickness of the sound insulation cover are limited.
The three elements of noise propagation include the sound source, medium and receptor, and with respect to the method of noise management, noise reduction at the sound source is generally the most effective and economical noise control measure. Sound insulation is a noise reduction measure commonly used in noise control engineering, sound insulation and noise reduction technologies are generally realized by increasing the thickness or density of sound insulation materials or structures, however, low-frequency noise has strong penetrating power and is difficult to separate, in practical production and application, certain requirements are required on the weight and thickness of a sound insulation device, the sound insulation device needs to be installed conveniently, an existing common light and thin sound insulation structure only has a good sound insulation effect on medium and high frequencies, and a low-frequency section cannot play a good sound insulation effect. Therefore, how to reduce the weight and reduce the thickness without reducing the noise, especially the low-frequency noise, is of great significance to the military and civil fields.
Disclosure of Invention
In order to make up the defect of the noise isolation effect of the existing light and thin sound insulation device on noise, particularly low-frequency-band noise, the invention provides a light and thin composite sound insulation structure based on an acoustic super-surface and a sound insulation and vibration reduction method, which solve the contradiction between the quality and thickness of the sound insulation structure and the sound insulation effect, realize broadband sound insulation by using smaller density and thinner thickness on the premise of ensuring the structural strength, and particularly have excellent sound insulation effect on low-frequency noise below 200 Hz.
The technical scheme adopted by the invention is as follows:
the invention provides a light and thin composite sound insulation structure based on an acoustic super surface, which comprises: the sound source side surface sound insulation layer 1, the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3; the middle sound insulation layer 2 is sandwiched between the sound source side surface sound insulation layer 1 and the sound insulation side surface sound insulation layer 3; a space formed between the middle sound insulation layer 2 and the sound source side surface sound insulation layer 1 is an upper layer space; the space formed between the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3 is a lower layer space;
a plurality of first convex grooves 6 are arranged on the reverse side of the sound source side surface sound insulation layer 1; the front surface of the middle sound insulation layer 2 is provided with a plurality of grooves 7; the first convex groove 6 of the sound source side surface sound insulation layer 1 is inserted into the groove 7 of the middle sound insulation layer 2, so that an upper layer space formed between the sound source side surface sound insulation layer 1 and the middle sound insulation layer 2 is divided into a plurality of upper layer subspaces; each of said upper subspaces forming an upper sound absorption layer 4 for arranging gradient foam cells 9; wherein, the gap between the gradient foam unit 9 and the sound source side surface sound insulation layer 1 and the gap between the first convex groove 6 and the groove 7 form an upper layer sound absorption layer air cavity 14;
a plurality of second convex grooves 8 are formed in the reverse side of the middle sound insulation layer 2, so that a lower layer space formed between the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3 is divided into a plurality of lower layer subspaces; and each lower layer subspace forms a lower layer vibration-damping sound-absorbing layer 5 for arranging vibration-damping sound-absorbing materials.
Preferably, the first convex groove 6 and the front surface of the middle sound insulation layer 2 have a gap; specifically, a gap is formed between the first convex groove 6 and the bottom surface of the groove 7; a gap is formed between the top of the groove 7 and the reverse side of the sound source side surface sound insulation layer 1;
the cross section of the first convex groove 6 and the cross section of the groove 7 are both rectangular; the first convex groove 6 and the groove height of the groove 7 are smaller than the height of the upper sound absorption layer 4, larger than 1/2 the height of the upper sound absorption layer 4 and are 1-10 mm.
Preferably, the first convex groove 6 and the concave groove 7 are symmetrical about a central axis, the groove 7 has a groove width larger than that of the first convex groove 6, and a gap formed between the concave groove 7 and the first convex groove 6 is a first sound absorption layer air cavity 14.1;
the groove width of the groove 7 is 2-40 mm, and the groove width of the first convex groove 6 is 1-10 mm.
Preferably, the first convex grooves 6 are convex grooves arranged in parallel at equal intervals; the grooves 7 are equidistantly and parallelly arranged; the upper-layer space is divided into a plurality of rectangular upper-layer subspaces which are arranged in parallel through the matching of the first convex groove 6 and the groove 7;
or
The first convex grooves 6 are convex grooves which are uniformly and vertically arranged in a transverse and longitudinal direction; the grooves 7 are uniformly and vertically arranged in the transverse and longitudinal directions; the upper-layer space is divided into a plurality of upper-layer subspaces which are arranged in a matrix form through the matching of the first convex grooves 6 and the concave grooves 7; the groove 7 is grooved and avoided at the cross point, and the first convex groove 6 and the groove 7 are ensured not to be contacted with each other.
Preferably, the second convex groove 8 is longitudinally aligned with the first convex groove 6, and the second convex groove 8 is in contact with the reverse side of the sound insulation side surface sound insulation layer 3, namely: the groove height of the second convex groove 8 is equal to the height of the lower vibration-damping sound-absorbing layer 5, and the groove width of the second convex groove 8 is 1-10 mm.
Preferably, the gradient foam unit 9 comprises n foam blocks with equal width and sequentially decreasing height; wherein the width of each foam block is d/n, and d is the total width of the gradient foam unit 9; the n foam block heights are designed as follows: enabling the phase response of each foam block to generate linear phase gradient change, enabling the range of the linear phase gradient change to cover 0-2 pi, and realizing abnormal control on sound waves;
in the gradient foam unit 9, a partition plate 10 with the height slightly lower than that of the upper sound absorption layer 4 is arranged between two adjacent foam blocks and on the outer side of the foam blocks;
and a gap formed between the gradient foam unit 9 and the sound source side surface sound insulation layer 1 is a second sound absorption layer air cavity 14.2.
Preferably, the material of the foam blocks is melamine foam, and the number n of the foam blocks included in the gradient foam unit 9 is 4 or 8.
Preferably, each of the lower subspaces forms a lower vibration-damping sound-absorbing layer 5 for arranging vibration-damping sound-absorbing materials, specifically:
determining the modal vibration mode corresponding to each lower subspace according to the vibration displacement response simulation result of the sound insulation structure, and arranging a constraint damping material 11 in the lower subspace corresponding to the generation position of the front 6-order modal main array mode; and arranging a free damping material 12 in a lower-layer subspace corresponding to the generation position of the first 6-order modal sub-array type, wherein the rest lower-layer subspace is a lower-layer vibration reduction sound absorption layer air cavity 13.
Preferably, the sound source side surface sound insulation layer 1, the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3 are 0.5-10 mm in thickness, the upper layer sound absorption layer 4 is 5-50 mm in thickness, and the lower layer vibration reduction sound absorption layer 5 is 1-10 mm in thickness;
the sound source side surface sound insulation layer 1, the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3 are made of aluminum alloy or composite materials.
The invention also provides a sound insulation method of the light and thin composite sound insulation structure based on the acoustic super-surface, which comprises the following steps:
1) incident sound waves reach the sound source side surface sound insulation layer 1, and reflection and transmission are generated on the surface of the sound source side surface sound insulation layer 1; wherein, a large amount of sound waves in the incident sound waves are reflected by the sound source side surface sound insulation layer 1 and are isolated; a small amount of incident sound waves penetrate through the sound insulation layer 1 on the side surface of the sound source to form transmission sound waves;
2) the transmitted sound wave reaches the gradient foam unit 9, the surface of the gradient foam unit 9 is a sub-wavelength acoustic super surface, the transmitted sound wave generates abnormal reflection and incidence on the sub-wavelength acoustic super surface, and the period length of the gradient foam unit 9 is smaller than a half wavelength, namely: let λ beiThe/d is more than or equal to 2, the high-order reflected wave of low-frequency-band noise can be eliminated, the sound absorption coefficient is basically kept unchanged when sound waves are incident from various angles, and therefore the gradient foam is realizedPrimary absorption of the transmitted acoustic wave by the cell 9;
in addition, the sound waves which are abnormally reflected are generated on the sub-wavelength acoustic super surface, and the sound waves which are reflected between the first convex groove 6 and the groove 7 are dissipated in the air cavity 14 of the upper sound absorption layer in a resonant mode, so that the aim of improving low-frequency noise absorption is fulfilled;
3) the unabsorbed transmitted sound waves reach the middle sound insulation layer 2, are reflected by the middle sound insulation layer 2, and reflected waves enter the gradient foam unit 9, so that secondary absorption of the gradient foam unit 9 on the reflected waves is realized;
the lower vibration-damping sound-absorbing layer 5 is regularly provided with a constrained damping material 11, a free damping material 12 and a lower vibration-damping sound-absorbing layer air cavity 13; wherein, the lower vibration-damping sound-absorbing layer air cavity 13 absorbs a small amount of transmitted sound waves passing through the middle sound-insulating layer 2 again; the constrained damping material 11 and the free damping material 12 are used for inhibiting and weakening resonance and anastomosis effects, so that most of transmitted sound waves are isolated and absorbed, and a broadband sound insulation effect is achieved.
The light and thin composite sound insulation structure and the sound insulation method based on the acoustic super surface have the following advantages:
the light and thin composite sound insulation structure and the sound insulation method based on the acoustic super surface, provided by the invention, have the sound insulation plate with the periodic structure array, are simple in structure, easy to process, splice and assemble, low in cost, large in structural strength and rigidity, small in density, light in weight, thin in thickness, fireproof and heat-insulating, can be applied to airplane bodies, ship cabins, building walls and industrial sound insulation cover structures, have a broadband sound insulation effect, particularly have an excellent effect of blocking low-frequency-band noise, and can realize higher sound insulation by matching with the design of the sub-wavelength acoustic super surface in the sound absorption layer and the application of damping materials.
Other features and characteristics of the present invention will be described in detail in several embodiments based on the design of the present sound insulation structure.
Drawings
Fig. 1 is a cross-sectional view of a light and thin composite sound insulation structure based on an acoustic super-surface provided by the invention;
FIG. 2 is a cross-sectional view of a three-layer sound barrier provided by the present invention;
FIG. 3 is a schematic structural diagram of a three-layer sound-insulating board provided by the present invention;
FIG. 4 is a diagram of the arrangement of gradient foam cells in an upper sound-absorbing layer provided by the present invention;
FIG. 5 is a schematic diagram of a subwavelength acoustic super-surface structure of a gradient foam cell;
FIG. 6 is a diagram of the arrangement of the lower vibration-damping and sound-absorbing layer provided by the invention;
FIG. 7 is a diagram illustrating the transmission attenuation of sound waves in the sound-insulating panel provided by the present invention;
FIG. 8 is a schematic structural view of a sound-insulating cover to which the sound-insulating structure of the present invention is applied;
FIG. 9 is a graph of sound insulation measured by the sound insulation cover experiment of the present invention;
wherein:
1-sound source side surface sound insulation layer; 2-middle sound insulation layer; 3-sound insulation layer on sound insulation side surface; 4-upper sound absorption layer; 5-lower vibration damping sound absorption layer; 6-first tongue; 7, a groove; 8-second tongue; 9-gradient foam unit; 10-a separator; 11-a constrained damping material; 12-a free damping material; 13-lower vibration damping sound absorption layer air cavity; 14-upper sound absorption layer air cavity; 14.1 — a first acoustical layer air cavity; 14.2-a second acoustical layer air cavity; 15-front wall board of sound insulation cover; 16-side panel wall of sound insulation cover.
Detailed Description
The following further describes the embodiments of the present invention with reference to the drawings. The illustrative embodiments of the present invention and their description are provided to illustrate the present invention and are not intended to be exhaustive of all embodiments in accordance with the invention. It is to be understood that this structure may be modified in part or combined for use in other embodiments without departing from the scope of the invention.
In the following detailed description, use of the directional terms "upper, middle, lower, positive and negative" in connection with the description of the invention generally refer to the upper, middle, lower, positive and negative dimensions of the drawing. The components of embodiments of the present invention can be positioned in a variety of different orientations and are not intended to be unduly limiting.
The invention provides a light and thin composite sound insulation structure based on an acoustic super-surface, which has the advantages of simple structure, easiness in processing, splicing and assembling, low cost, high structural strength and rigidity, small density, thin thickness, fire prevention, heat preservation, broadband sound insulation effect, excellent blocking effect on low-frequency-band noise, capability of realizing higher sound insulation on specific-frequency-band noise by matching with the design of a sub-wavelength acoustic super-surface in a sound absorption layer and the application of a damping material, and good application prospect.
Referring to fig. 1, the light and thin composite sound insulation structure based on an acoustic super surface provided by the present invention is composed of three layers, and with reference to fig. 2 and 3, includes: the sound source side surface sound insulation layer 1, the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3; the middle sound insulation layer 2 is sandwiched between the sound source side surface sound insulation layer 1 and the sound insulation side surface sound insulation layer 3; a space formed between the middle sound insulation layer 2 and the sound insulation layer 1 on the surface of the sound source side is an upper layer space; a space formed between the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3 is a lower layer space;
a plurality of first convex grooves 6 are arranged on the reverse side of the sound insulation layer 1 on the side surface of the sound source; the front surface of the middle sound insulation layer 2 is provided with a plurality of grooves 7; the first convex groove 6 of the sound source side surface sound insulation layer 1 is inserted into the groove 7 of the middle sound insulation layer 2, so that an upper layer space formed between the sound source side surface sound insulation layer 1 and the middle sound insulation layer 2 is divided into a plurality of upper layer subspaces;
each upper subspace forms an upper sound absorption layer 4 for arranging gradient foam units 9; wherein, a gap between the gradient foam unit 9 and the sound source side surface sound insulation layer 1 and a gap between the first convex groove 6 and the groove 7 form an upper layer sound absorption layer air cavity 14;
the back surface of the middle sound insulation layer 2 is provided with a plurality of second convex grooves 8, so that a lower layer space formed between the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3 is divided into a plurality of lower layer subspaces; each lower subspace forms a lower vibration-damping sound-absorbing layer 5 for arranging vibration-damping sound-absorbing materials.
The main structure of the present invention is described in detail below:
sound source side surface sound insulation layer 1, middle sound insulation layer 2 and sound insulation side surface sound insulation layer 3
The sound source side surface sound insulation layer 1, the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3 are 0.5-10 mm in thickness, and the sound source side surface sound insulation layer 1, the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3 are made of aluminum alloy or composite materials.
Referring to fig. 2, the sound source side surface sound insulation layer 1, the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3 can be formed by milling aluminum magnesium alloy, melamine foam is used between the three sound insulation layers, and damping materials and elastic members are used for supporting and connecting. The melamine foam can reach the B1 level specified in GB/T8624-2012 in the flame retardant grade without adding any flame retardant medium, and has excellent sound absorption, low volume weight and heat preservation and insulation properties, so the sound insulation board has wide use scenes.
(II) Structure of first tongue 6 and groove 7
A plurality of first convex grooves 6 are arranged on the reverse side of the sound insulation layer 1 on the side surface of the sound source; the front surface of the middle sound insulation layer 2 is provided with a plurality of grooves 7; the first convex groove 6 of the sound source side surface sound insulation layer 1 is inserted into the groove 7 of the middle sound insulation layer 2; in practical application, the first convex groove 6 can be used as a reinforcing rib of the sound source side surface sound insulation layer 1 and is integrally formed with the sound source side surface sound insulation layer 1; similarly, the groove 7 can be used as a reinforcing rib of the middle sound insulation layer 2 and is integrally formed with the middle sound insulation layer 2; and an integrated forming mode is adopted, so that the structural rigidity of the sound insulation layer is improved, and the volume utilization rate of the structure is increased.
The arrangement of the first tongue 6 and the groove 7 may be:
the first convex grooves 6 are equidistantly and parallelly arranged convex grooves; the grooves 7 are equidistantly and parallelly arranged; the upper-layer space is divided into a plurality of rectangular upper-layer subspaces which are arranged in parallel through the matching of the first convex groove 6 and the groove 7;
or
The first convex groove 6 is a convex groove which is uniformly and vertically arranged in the transverse and longitudinal directions; the grooves 7 are uniformly and vertically arranged in the transverse and longitudinal directions; the upper-layer space is divided into a plurality of upper-layer subspaces arranged in a matrix form through the matching of the first convex grooves 6 and the grooves 7; the groove 7 is grooved and avoided at the cross point, and the first convex groove 6 and the groove 7 are ensured not to be in rigid contact with each other, so that an acoustic bridge is prevented from being formed, and the sound insulation quantity is reduced.
As a specific implementation, the following design parameters can be adopted for the first tongue 6 and the groove 7:
the cross section of the first convex groove 6 and the cross section of the groove 7 are both rectangular; the groove height of the first convex groove 6 and the groove 7 is smaller than the height of the upper sound absorption layer 4, is larger than 1/2 of the height of the upper sound absorption layer 4, and is 1-10 mm. Wherein, the thickness of the upper sound absorption layer 4 is 5-50 mm.
The first convex groove 6 and the groove 7 are symmetrical about the central axis, and the groove width of the groove 7 is larger than that of the first convex groove 6; for example, the groove width of the concave groove 7 is 2 to 40mm, and the groove width of the first convex groove 6 is 1 to 10 mm.
A gap is formed between the first convex groove 6 and the front surface of the middle sound insulation layer 2; specifically, a gap is formed between the bottom surfaces of the first convex groove 6 and the groove 7; a gap is formed between the top of the groove 7 and the reverse side of the sound source side surface sound insulation layer 1; a gap formed between the groove 7 and the first convex groove 6 is a first sound absorption layer air cavity 14.1;
(III) Structure of second tongue 8 and first tongue 6
The reverse side on middle sound insulation layer 2 sets up a plurality of second tongue 8, and second tongue 8 vertically aligns with first tongue 6, and second tongue 8 contacts with the reverse side on sound insulation side surface sound insulation layer 3, promptly: the groove height of the second convex groove 8 is equal to the height of the lower vibration-damping sound-absorbing layer 5, and the groove width of the second convex groove 8 is 1-10 mm.
Therefore, in the invention, the reverse side of the sound source side surface sound insulation layer 1 is provided with a first convex groove 6 serving as a transverse and longitudinal reinforcing rib, the front side of the middle sound insulation layer 2 is provided with a groove 7 serving as a reinforcing rib, and the reverse side of the middle sound insulation layer 2 is provided with a second convex groove 8 serving as a reinforcing rib; the sound insulation side surface sound insulation layer 3 is a flat plate, a first convex groove 6 on the reverse side of the sound source side surface sound insulation layer 1 and a groove 7 on the front side of the middle sound insulation layer 2 are inserted into each other, and a second convex groove 8 arranged on the reverse side of the middle sound insulation layer 2 is consistent with the position of the first convex groove 6 on the sound source side surface sound insulation layer 1.
(IV) gradient foam unit 9
Each upper subspace forms an upper sound absorption layer 4 for arranging gradient foam units 9; with reference to fig. 4 and 5, the gradient foam unit 9 includes n foam blocks with equal width and sequentially decreasing height; wherein the width of each foam block is d/n, and d is the total width of the gradient foam unit 9; the n foam block heights are designed as follows: enabling the phase response of each foam block to generate linear phase gradient change, enabling the range of the linear phase gradient change to cover 0-2 pi, and realizing abnormal control on sound waves; wherein, the material of the foam block includes but is not limited to melamine foam, and the number n of the foam blocks included in the gradient foam unit 9 can be flexibly set according to actual needs, and for example, can be 4 or 8. In the figures, each gradient foam unit 9 is provided with 4 foam blocks, respectively: foam block P1, foam block P2, foam block P3, and foam block P4. Therefore, in the present invention, the n foam blocks are periodically arranged as a gradient foam unit.
The gap formed between the gradient foam unit 9 and the sound source side surface sound insulation layer 1 is a second sound absorption layer air cavity 14.2.
By changing the thickness of the gradient foam units 9 and the thickness of the air cavity 14.2 of the second sound absorption layer, the phase of the surface of the structure can be adjusted, the range of the phase covers 0-2 pi, the phase difference between two adjacent gradient foam units 9 is kept consistent, and the sound wave phase can be adjusted and controlled within the range of 0-2 pi.
As shown in fig. 5, in the gradient foam unit 9, a partition plate 10 with a height slightly lower than that of the upper sound absorption layer 4 is arranged between two adjacent foam blocks and on the outer side of the foam blocks; the separator 10 may be made of an aluminum sheet. By arranging the partition plate 10, the sound waves incident in each gradient foam unit 9 can only act on the medium in the gradient foam unit 9 and are not influenced by the adjacent gradient foam units 9.
The length of the gradient foam unit 9 is d, namely the length of a block surrounded by the grooves 7 arranged on the front surface of the middle sound insulation layer 2, and in the same gradient foam unit 9, each foam block is arranged according to d phit-2 pi/d negative gradient alignment, according to the formula:
θrr: acoustic reflection angle or refraction angle;
m: the order of the diffracted wave;
d: the width of the foam cells;
λi: incident acoustic wave wavelength in each direction;
θi: the incident sound wave angle in each direction.
When the length d of the gradient foam cells 9 is less than half a wavelength, i.e. lambdaiWhen the/d is more than or equal to 2, high-order reflection can be eliminated, only specular reflection and direct transmission are generated on the surface of the material, the sound absorption coefficient is basically unchanged along with the incident angle of sound waves in the designed frequency band, and a good sound absorption effect is achieved.
(V) lower vibration-damping sound-absorbing layer 5
Each lower-layer subspace forms a lower-layer vibration-damping sound-absorbing layer 5 for arranging vibration-damping sound-absorbing materials, and the thickness of the lower-layer vibration-damping sound-absorbing layer 5 is 1-10 mm;
the method specifically comprises the following steps:
determining the modal vibration mode corresponding to each lower subspace according to the vibration displacement response simulation result of the sound insulation structure, and arranging a constraint damping material 11 in the lower subspace corresponding to the generation position of the front 6-order modal main array mode; and arranging a free damping material 12 in a lower-layer subspace corresponding to the generation position of the first 6-order modal sub-array type, wherein the rest lower-layer subspace is a lower-layer vibration reduction sound absorption layer air cavity 13. Thereby the lower vibration-damping sound-absorbing layer 5 forms a combined arrangement of damping material and air.
The invention also provides a sound insulation method of the light and thin composite sound insulation structure based on the acoustic super-surface, which refers to fig. 7, and is a transmission attenuation mode of sound waves in the sound insulation structure, and the method comprises the following steps:
1) incident sound waves reach the sound source side surface sound insulation layer 1, and reflection and transmission are generated on the surface of the sound source side surface sound insulation layer 1; wherein, a large amount of sound waves in the incident sound waves are reflected by the sound source side surface sound insulation layer 1 and are isolated; a small amount of incident sound waves penetrate through the sound insulation layer 1 on the side surface of the sound source to form transmission sound waves;
2) the transmitted sound wave reaches the gradient foam unit 9, the surface of the gradient foam unit 9 is a sub-wavelength acoustic super surface, and the transmitted sound wave is in sub-wavelength soundThe optical super surface generates abnormal reflection and incidence, so that the period length of the gradient foam unit 9 is less than half wavelength, namely: let λ beiThe/d is more than or equal to 2, so that high-order reflected waves of low-frequency-band noise can be eliminated, and the sound absorption coefficient of sound waves is basically kept unchanged when the sound waves are incident from various angles, so that the primary absorption of the gradient foam unit 9 on the transmitted sound waves is realized;
in addition, the sound waves which are abnormally reflected are generated on the sub-wavelength acoustic super surface, and the sound waves which are reflected between the first convex groove 6 and the groove 7 are dissipated in the air cavity 14 of the upper sound absorption layer in a resonant mode, so that the aim of improving low-frequency noise absorption is fulfilled;
3) the unabsorbed transmitted sound waves reach the middle sound insulation layer 2, are reflected by the middle sound insulation layer 2, and reflected waves enter the gradient foam unit 9, so that secondary absorption of the gradient foam unit 9 on the reflected waves is realized;
the lower vibration-damping sound-absorbing layer 5 is regularly provided with a constrained damping material 11, a free damping material 12 and a lower vibration-damping sound-absorbing layer air cavity 13; wherein, the lower vibration-damping sound-absorbing layer air cavity 13 absorbs a small amount of transmitted sound waves passing through the middle sound-insulating layer 2 again; the constrained damping material 11 and the free damping material 12 are used for inhibiting and weakening resonance and anastomosis effects, so that most of transmitted sound waves are isolated and absorbed, and a broadband sound insulation effect is achieved.
Therefore, the light and thin composite sound insulation structure and the sound insulation method based on the acoustic super surface, provided by the invention, have the sound insulation plates with periodic structural arrays, are simple in structure, easy to process, splice and assemble, low in cost, high in structural strength and rigidity, low in density, light in weight, thin in thickness, fireproof and heat-insulating, can be applied to airplane bodies, ship cabins, building walls and industrial sound insulation cover structures, have a broadband sound insulation effect, particularly have an excellent effect of blocking low-frequency-band noise, and can realize higher sound insulation by matching with the application of subwavelength acoustic super surface design and damping materials in a sound absorption layer.
The light and thin composite sound insulation structure based on the acoustic super surface can be used for manufacturing any type of sound insulation products, and the application scene of the light and thin composite sound insulation structure is described by taking the industrial sound insulation cover shown in fig. 8 as an example:
referring to fig. 8, the invention provides an industrial sound insulation cover applying the light and thin composite sound insulation structure based on the acoustic super surface. The sound insulation cover is formed by combining eight sound insulation plates with composite structures, and the combination mode is screw connection. The front wall plate 15 of the sound insulation cover adopts a light and thin composite sound insulation structure designed by the invention, the upper sound absorption layer 4 adopts uniform melamine foam, the side wall plates 16 of the sound insulation cover are seven in total, the basic structural parameters are consistent with the invention, and the difference is that reinforcing ribs are removed, and only the reinforcing frame of the middle sound insulation layer is reserved.
The whole material of sound-proof cover is aluminium magnesium alloy, sound source side surface sound insulating layer 1, middle sound insulating layer 2 and sound insulation side surface sound insulating layer thickness keep unanimous, for 1mm, 4 thickness on upper sound absorbing layer between sound source side surface sound insulating layer 1 and the middle sound insulating layer 2 are 8mm, 5 thickness on lower floor's damping sound absorbing layer between middle sound insulating layer 2 and the sound insulation side surface sound insulating layer 3 are 2mm, strengthen frame both sides protruding height and each sound absorbing layer height keep unanimous, the width is 8 mm. The total thickness of the sound insulation board is 13mm, and the overall density of the sound insulation cover is 181.28kg/m3. The height of the first convex groove 6 of the sound source side sound insulation layer 1 and the height of the groove 7 on the front side of the middle sound insulation layer 2 are both 6mm, the height of the second convex groove 8 on the back side of the middle sound insulation layer 2 is 2mm, the grooves 7 on the front side and the back side of the middle sound insulation layer 2 and the second convex grooves 8 are vertically and uniformly arranged, the upper sound absorption layer 4 and the lower vibration attenuation sound absorption layer 5 are divided into block areas with the same size, and the gradient foam units 9 and the damping materials can be conveniently arranged.
Inside the sound-proof cover, for low cost and extremely thin and light consideration, gradient foam unit 9 only adopts 1 even melamine foam, as the sound absorption layer between sound source side surface sound-proof layer 1 and middle sound-proof layer 2 of side sound-proof board, promptly: n is 1; the melamine foam is flush with the upper sound absorption layer 4 in height; meanwhile, in order to fully utilize the air cavity 14 of the upper sound absorption layer to absorb sound, the upper sound absorption layer 4 between the sound source side surface sound insulation layer 1 and the middle sound insulation layer 2 of the front sound insulation plate is not filled with foam. The lower damping sound absorption layer 5 between the middle sound insulation layer 2 and the sound insulation side surface sound insulation layer 3 responds to a simulation result according to vibration displacement of the front sound insulation plate, a 6-order mode main matrix type in the front is used for restraining a damping material 11, a free damping material 12 is used in a secondary matrix type position, the total use area is controlled to be between 60% and 75% of the total area, and the rest space is an air cavity 13 of the lower damping sound absorption layer.
The contact position of the sound insulation cover and the ground is pasted with a damping material for vibration isolation so as to reduce the solid borne sound. Wax sealing is used at the gap of the sound insulation cover. The sound insulation performance of the sound insulation cover can be represented by the reduction value of the sound pressure level according to the selected method by testing the whole sound insulation quantity of the sound insulation cover according to the test (marked) of the sound insulation performance of the GB T18699.1-2002 sound insulation cover under the condition of part 1 laboratory, and the obtained result is shown in figure 9, as can be seen from figure 9, the sound insulation quantity of the sound insulation structure in the preferred embodiment of the invention is good in the whole full frequency band of 50Hz-10000Hz in one third octave, the sound insulation effect is excellent below 200Hz and above 1250Hz, and a remarkable sound insulation peak appears near 80 Hz.
It is noted that the light and thin composite sound insulation structure based on the acoustic super surface of the present invention can be used for various purposes, such as cabin wall panels, building walls, sound insulation covers, etc., as a general sound insulation structure, and the above specific embodiments only illustrate the preferred embodiments of the present invention, but any combination of the different embodiments of the present invention can be made, as long as the concept of the present invention is not violated, and the same shall be considered as the disclosure of the present invention, and the present invention shall be protected.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and improvements can be made without departing from the principle of the present invention, and such modifications and improvements should also be considered within the scope of the present invention.
Claims (9)
1. The utility model provides a frivolous compound sound insulation structure based on super surface of acoustics which characterized in that includes: the sound source side sound insulation layer (1), the middle sound insulation layer (2) and the sound insulation side sound insulation layer (3); the middle sound insulation layer (2) is sandwiched between the sound source side surface sound insulation layer (1) and the sound insulation side surface sound insulation layer (3); a space formed between the middle sound insulation layer (2) and the sound source side surface sound insulation layer (1) is an upper layer space; a space formed between the middle sound insulation layer (2) and the sound insulation side surface sound insulation layer (3) is a lower layer space;
a plurality of first convex grooves (6) are arranged on the reverse side of the sound source side surface sound insulation layer (1); the front surface of the middle sound insulation layer (2) is provided with a plurality of grooves (7); the first convex groove (6) of the sound source side surface sound insulation layer (1) is inserted into the groove (7) of the middle sound insulation layer (2), and then an upper layer space formed between the sound source side surface sound insulation layer (1) and the middle sound insulation layer (2) is divided into a plurality of upper layer subspaces; each of said upper subspaces forming an upper sound absorption layer (4) for arranging gradient foam cells (9); wherein a gap between the gradient foam unit (9) and the sound source side surface sound insulation layer (1) and a gap between the first convex groove (6) and the groove (7) form an upper sound absorption layer air cavity (14);
a plurality of second convex grooves (8) are arranged on the reverse side of the middle sound insulation layer (2), so that a lower layer space formed between the middle sound insulation layer (2) and the sound insulation side surface sound insulation layer (3) is divided into a plurality of lower layer subspaces; each lower layer subspace forms a lower layer vibration-damping sound-absorbing layer (5) for arranging vibration-damping sound-absorbing materials;
wherein a gap is formed between the first convex groove (6) and the front surface of the middle sound insulation layer (2); specifically, a gap is formed between the first convex groove (6) and the groove bottom surface of the groove (7); a gap is formed between the top of the groove (7) and the reverse side of the sound source side surface sound insulation layer (1);
the cross section of the first convex groove (6) and the cross section of the groove (7) are both rectangular; the first convex groove (6) and the groove height of the groove (7) are smaller than the height of the upper sound absorption layer (4), larger than 1/2 the height of the upper sound absorption layer (4), and are 1-10 mm.
2. The ultra-acoustic-surface-based lightweight and thin composite sound insulation structure according to claim 1, wherein the first convex groove (6) and the concave groove (7) are symmetrical about a central axis, the groove width of the concave groove (7) is larger than that of the first convex groove (6), and a gap formed between the concave groove (7) and the first convex groove (6) is a first sound absorption layer air cavity (14.1);
the groove width of the groove (7) is 2-40 mm, and the groove width of the first convex groove (6) is 1-10 mm.
3. The ultra-surface acoustic-based light-thin composite sound insulation structure is characterized in that the first convex grooves (6) are equidistantly arranged in parallel; the grooves (7) are equidistantly and parallelly arranged; the upper-layer space is divided into a plurality of rectangular upper-layer subspaces which are arranged in parallel through the matching of the first convex groove (6) and the groove (7);
or
The first convex grooves (6) are convex grooves which are uniformly and vertically arranged in the transverse and longitudinal directions; the grooves (7) are uniformly and vertically arranged in the transverse and longitudinal directions; the upper-layer space is divided into a plurality of upper-layer subspaces which are arranged in a matrix form through the matching of the first convex grooves (6) and the grooves (7); the groove (7) is grooved and avoided at the cross point, and the first convex groove (6) and the groove (7) are ensured not to be contacted with each other.
4. The acoustic super-surface based lightweight and thin composite sound insulation structure according to claim 1, wherein the second tongue (8) is longitudinally aligned with the first tongue (6), and the second tongue (8) is in contact with the reverse side of the sound insulation side surface sound insulation layer (3), that is: the groove height of second tongue (8) equals the height of lower floor's damping sound absorbing layer (5), the groove width of second tongue (8) is 1 ~ 10 mm.
5. The acoustic super surface based lightweight thin composite sound insulation structure according to claim 1, wherein the gradient foam unit (9) comprises n foam blocks with equal width and sequentially decreasing height; wherein the width of each foam block is d/n, and d is the total width of the gradient foam unit (9); the n foam block heights are designed as follows: enabling the phase response of each foam block to generate linear phase gradient change, enabling the range of the linear phase gradient change to cover 0-2 pi, and realizing abnormal control on sound waves;
in the gradient foam unit (9), a clapboard (10) with the height slightly lower than that of the upper sound absorption layer (4) is arranged between two adjacent foam blocks and on the outer side of the foam blocks;
and a gap formed between the gradient foam unit (9) and the sound source side surface sound insulation layer (1) is a second sound absorption layer air cavity (14.2).
6. The acoustically super-surface based lightweight thin composite acoustical structure of claim 5 wherein the foam blocks are made of melamine foam and the gradient foam units (9) comprise foam blocks having a number n of 4 or 8.
7. The ultra-acoustic-surface-based light-thin composite sound insulation structure according to claim 1, wherein each of the lower subspaces forms a lower vibration-damping and sound-absorbing layer (5) for arranging vibration-damping and sound-absorbing materials, specifically:
according to the vibration displacement response simulation result of the sound insulation structure, determining the modal vibration mode corresponding to each lower-layer subspace, and arranging a constraint damping material (11) in the lower-layer subspace corresponding to the generation position of the front 6-order modal main array mode; and arranging a free damping material (12) in a lower-layer subspace corresponding to the occurrence position of the first 6-order modal sub-array type, wherein the rest lower-layer subspace is an air cavity (13) of a lower-layer vibration reduction sound absorption layer.
8. The ultra-surface acoustic-based light and thin composite sound insulation structure is characterized in that the sound source side sound insulation layer (1), the middle sound insulation layer (2) and the sound insulation side sound insulation layer (3) are 0.5-10 mm thick, the upper sound absorption layer (4) is 5-50 mm thick, and the lower vibration attenuation sound absorption layer (5) is 1-10 mm thick;
the sound source side surface sound insulation layer (1), the middle sound insulation layer (2) and the sound insulation side surface sound insulation layer (3) are made of aluminum alloy or composite materials.
9. A sound insulation method of a light and thin composite sound insulation structure based on an acoustic super surface according to any one of claims 1 to 8, characterized by comprising the following steps:
1) incident sound waves reach the sound source side sound insulation layer (1), and reflection and transmission are generated on the surface of the sound source side sound insulation layer (1); a large amount of incident sound waves are reflected by the sound insulation layer (1) on the side surface of the sound source and are isolated; a small amount of incident sound waves penetrate through the sound source side surface sound insulation layer (1) to form transmission sound waves;
2) the transmitted sound wave reaches the gradient foam unit (9), the surface of the gradient foam unit (9) is a sub-wavelength acoustic super surface, the transmitted sound wave generates abnormal reflection and incidence on the sub-wavelength acoustic super surface, and the period length of the gradient foam unit (9) is smaller than a half wavelength, namely: let λ beiThe/d is more than or equal to 2, high-order reflected waves of low-frequency-band noise can be eliminated, and the sound absorption coefficient of sound waves is basically kept unchanged when the sound waves are incident from various angles, so that the primary absorption of the gradient foam unit (9) on the transmitted sound waves is realized;
in addition, the sound waves which are abnormally reflected are generated on the sub-wavelength acoustic super surface, the sound waves which are reflected between the first convex groove (6) and the groove (7) are subjected to resonant dissipation in an air cavity (14) of the upper sound absorption layer, and the purpose of improving low-frequency noise absorption is achieved;
3) the unabsorbed transmitted sound waves reach the middle sound insulation layer (2), are reflected by the middle sound insulation layer (2), and the reflected waves enter the gradient foam unit (9), so that secondary absorption of the gradient foam unit (9) on the reflected waves is realized;
the lower vibration-damping sound-absorbing layer (5) is regularly provided with a constrained damping material (11), a free damping material (12) and a lower vibration-damping sound-absorbing layer air cavity (13); wherein, the lower vibration-damping sound-absorbing layer air cavity (13) absorbs a small amount of transmitted sound waves passing through the middle sound-insulating layer (2) again; the constrained damping material (11) and the free damping material (12) are used for inhibiting and weakening resonance and anastomosis effect, thereby isolating and absorbing most of transmitted sound waves and achieving broadband sound insulation effect.
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| CN115394274B (en) * | 2022-08-30 | 2023-07-07 | 哈尔滨工程大学 | Multilayer composite efficient vibration reduction plate structure based on acoustic black hole effect |
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