Controllable sound absorption structure based on shape memory negative poisson's ratio material and application thereof

Abstract

The present application relates to the technical field of sound absorption structure, and particularly relates to a controllable sound absorption structure based on shape memory negative Poisson's ratio material and application thereof. The sound absorption structure is formed by multiple sound absorption units, the sound absorption unit made of shape memory negative Poisson's ratio material is a prism structure, there is only one edge between every two adjacent sound absorption units to be connected by rotating, and the sound absorption unit is provided with a sound elimination structure. When the sound absorption structure is in a sound absorption state, the side walls of adjacent sound absorption units are in close contact with each other. When the sound absorption structure is stimulated by external environment, the sound absorption structure is stretched to make the sound absorption units rotate with each other, a gap is formed between the sound absorption units, the sound absorption structure is in a sound transmission state, and the sound absorption structure can be restored to the sound absorption state again to realize controllable deformation. The sound absorption structure is in the sound transmission state or the sound absorption state by controlling the opening and closing of the gap, and the sound absorption effect and bandwidth of the sound absorption structure are controlled by controlling the size of the gap.

Description

Technical Field

[0001] This invention relates to the field of sound-absorbing structure technology, and in particular to a controllable sound-absorbing structure based on shape memory negative Poisson's ratio material and its application. Background Technology

[0002] With the accelerating pace of industrialization in modern society, noise from vehicles, factories, construction sites, and various entertainment facilities is increasingly impacting people's daily lives. The expanding noise range and prolonged duration are causing problems such as persistent mental agitation, hearing loss, and sleep deprivation, and even inducing a range of illnesses including neurasthenia, fatigue, hypertension, and cardiovascular disease. Therefore, noise reduction has become a research hotspot for scientists for nearly half a century.

[0003] Currently, setting up silencers and sound-absorbing structures to target noise sources has become a major direction in noise isolation research. However, this approach still has some drawbacks, mainly including: 1) It cannot effectively control the isolation of noise of different levels, often relying on experience or taking the average noise level to set isolation measures, resulting in incomplete sound insulation or waste of materials; 2) The same sound insulation material or structure has different isolation effects on noise of different frequencies, thus leading to unstable sound insulation effects or the need to set up multiple sound insulation devices.

[0004] Therefore, there is an urgent need for a controllable sound-absorbing structure and its application method that can adjust the sound insulation effect and sound absorption range. Summary of the Invention

[0005] This invention provides a controllable sound-absorbing structure based on shape memory negative Poisson's ratio material and its application, which can provide a controllable sound-absorbing structure and its application method that can adjust the sound insulation effect and sound absorption range.

[0006] In a first aspect, embodiments of the present invention provide a controllable sound-absorbing structure based on shape memory negative Poisson's ratio material, comprising a layered structure formed by multiple sound-absorbing units. The material used to prepare the sound-absorbing units includes shape memory negative Poisson's ratio material. Each sound-absorbing unit is a prism structure, with one and only one edge connecting each other between every two adjacent sound-absorbing units. The prism structure includes two prism faces and multiple sidewalls. A cavity is formed inside the prism structure. The two prism faces of the sound-absorbing units form the layers of the layered structure. The prism faces of the sound-absorbing units facing the same direction are provided with sound-absorbing structures.

[0007] When the sound-absorbing structure is in a sound-absorbing state, the sidewalls of adjacent sound-absorbing units are in close contact with each other. When the sound-absorbing structure is stimulated by the outside, it stretches and causes the sound-absorbing units to rotate relative to each other, forming a gap between the sound-absorbing units. The sound-absorbing structure is in a sound-passing state. When stimulated by the outside again, the sound-absorbing structure can return to a sound-absorbing state to achieve controllable deformation. By controlling the opening and closing of the gap, the sound-passing or sound-absorbing state of the sound-absorbing structure can be controlled. By controlling the size of the gap, the sound absorption effect and bandwidth of the sound-absorbing structure can be controlled.

[0008] 0 In one possible design, the sound-absorbing unit is fabricated using materials including shape memory alloys and shape-memory alloys.

[0009] Shape memory polymer.

[0010] In one possible design, the shape memory material is prepared using 4D printing technology.

[0011] In one possible design, the sound-absorbing structure includes sound-absorbing holes extending through the cylindrical surface.

[0012] In one possible design, the noise-absorbing structure includes a noise-absorbing membrane disposed on the cylindrical surface, the noise-absorbing membrane being flexible and having an uneven surface.

[0013] In one possible design, the sound-absorbing unit comprises a square prism structure.

[0014] In one possible design, the cavity of the sound-absorbing unit is provided with a partition that divides the cavity into two parts, and the partition is provided with the sound-absorbing structure.

[0015] In one possible design, the diameter of the sound-absorbing hole is 0.25–0.35 mm; the cavity of the sound-absorbing unit is provided with a partition, the partition divides the cavity into two parts, the partition is provided with the sound-absorbing structure, the distance between the cylindrical surface with the sound-absorbing structure and the partition is 25–35 mm, and the distance between the partition and the cylindrical surface without the sound-absorbing structure is 15–25 mm.

[0016] Secondly, embodiments of the present invention also provide an application of the sound-absorbing structure based on any one of the first aspects, including:

[0017] Cover the target with the sound-absorbing structure and stretch the sound-absorbing structure according to the usage requirements;

[0018] The stretching of the sound-absorbing structure includes:

[0019] The sound-absorbing structure is stretched perpendicular to its surface;

[0020] And / or,

[0021] The sound-absorbing structure is stretched parallel to its surface.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] In this embodiment, the sound-absorbing structure consists of multiple prismatic sound-absorbing units, which are connected by rotational prisms. Each sound-absorbing unit has a silencing structure on one cylindrical surface, and the unit is hollow, forming a cavity. The silencing structure on the cylindrical surface and the cavity provide excellent sound absorption and noise reduction. When the sound-absorbing structure is in a sound-absorbing state, the sound-absorbing units are tightly fitted together. When the structure is subjected to external stimuli (thermal or electrical), it softens and deforms, stretching the structure. Due to its negative Poisson's ratio, when subjected to tensile force in one direction, the direction perpendicular to the tensile force also exhibits an stretching effect. Thus, the entire structure is stretched, and the sound-absorbing units are stretched apart, remaining connected only at the connecting prisms, forming gaps. The structure is in a sound-passing state. After adjusting the size of the gaps and removing the stimulus, the structure can maintain this state without further stretching. Applying stimulation again to the structure in the sound-passing state restores it to its sound-absorbing state, achieving controllable deformation. During use, the sound-absorbing structure can be controlled to either allow sound to pass through or absorb sound, depending on the requirements. The opening and closing size of the gaps can also be controlled by adjusting the tensile force, thereby controlling the frequency and effect of sound attenuation. For example, in the roof of a stadium, sealing the gaps allows for sound absorption and wind protection, while deformation creating gaps allows for sound passage and ventilation. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a sound-absorbing structure provided in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the unstretched state of a sound-absorbing structure provided in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of a sound-absorbing structure in a stretched state according to an embodiment of the present invention;

[0028] Figure 4 This is a front view structural diagram of a sound-absorbing unit provided in an embodiment of the present invention;

[0029] Figure 5 This is a side view structural diagram of a sound-absorbing unit provided in an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram illustrating the sound absorption effect of a sound-absorbing structure provided in an embodiment of the present invention.

[0031] In the picture:

[0032] 1-Sound-absorbing unit;

[0033] 11-Cylindrical surface;

[0034] 12-Sidewall;

[0035] 13-Partition;

[0036] 14 - Sound-absorbing holes;

[0037] 15-Cavity. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] In the description of the embodiments of the present invention, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or stated, the term "multiple" refers to two or more; the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0040] In this specification, it should be understood that the directional terms such as "upper" and "lower" used in the description of the embodiments of the present invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of the present invention. Furthermore, in the context, it should also be understood that when it is mentioned that one element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0041] like Figures 1 to 5As shown, this embodiment of the invention provides a controllable sound absorption structure based on shape memory negative Poisson's ratio material, including a layered structure formed by multiple sound absorption units 1. The material used to prepare the sound absorption unit 1 includes shape memory negative Poisson's ratio material. The sound absorption unit 1 is a prism structure, with only one edge connecting each two adjacent sound absorption units 1 for rotational connection. The prism structure includes two prism faces 11 and multiple sidewalls 12. A cavity 15 is formed inside the prism structure. The two prism faces 11 of the sound absorption unit 1 form the layer of the layered structure. The prism faces 11 of the sound absorption unit 1 facing the same direction are provided with a sound-absorbing structure.

[0042] When the sound-absorbing structure is in a sound-absorbing state, the sidewalls 12 of adjacent sound-absorbing units 1 are in contact with each other. When the sound-absorbing structure is stimulated by the outside, it stretches the sound-absorbing structure and causes the sound-absorbing units 1 to rotate relative to each other, forming a gap between the sound-absorbing units 1. The sound-absorbing structure is in a sound-passing state. When stimulated by the outside again, the sound-absorbing structure can return to the sound-absorbing state to achieve controllable deformation. By controlling the opening and closing of the gap, the sound-passing or sound-absorbing of the sound-absorbing structure can be controlled. By controlling the size of the gap, the sound absorption effect and bandwidth of the sound-absorbing structure can be controlled.

[0043] In this embodiment, the sound-absorbing structure consists of multiple prism-structured sound-absorbing units 1, which are connected by prism rotation. Each sound-absorbing unit 1 has a sound-absorbing structure on one cylindrical surface, and the interior of the sound-absorbing unit 1 is hollow, forming a cavity 15. The sound-absorbing structure on the cylindrical surface and the cavity 15 provide excellent sound absorption and noise reduction effects. When the sound-absorbing structure is in a sound-absorbing state, the sound-absorbing units 1 are tightly fitted together. When the sound-absorbing structure is subjected to external stimuli (thermal or electrical stimulation), it softens and deforms, stretching the structure. Due to the negative Poisson's ratio, when subjected to tensile force in one direction, the direction perpendicular to the tensile force also forms an extension effect. Thus, the entire sound-absorbing structure is stretched, and the sound-absorbing units 1 are stretched apart, remaining connected only at the connecting prisms, forming gaps. The sound-absorbing structure is in a sound-passing state. After adjusting the size of the gaps and removing the stimulus, the sound-absorbing structure can maintain the sound-passing state without stretching. Applying stimulation to the sound-absorbing structure again in the sound-passing state can restore it to the sound-absorbing state, achieving controllable deformation. During use, the sound-absorbing structure can be controlled to either allow sound to pass through or absorb sound, depending on the requirements. The opening and closing size of the gaps can also be controlled by adjusting the tensile force, thereby controlling the frequency and effect of sound attenuation. For example, in the roof of a stadium, sealing the gaps allows for sound absorption and wind protection, while deformation creating gaps allows for sound passage and ventilation.

[0044] It should be noted that the cavity 15 structure of the sound-absorbing unit 1 forms a resonant sound-absorbing cavity, which can achieve a resonant sound absorption peak within a certain range. By adjusting the depth of the cavity 15, the absorption of external sounds of different frequencies / bandwidths can be achieved.

[0045] In this embodiment, the cylindrical surface 11 without a sound-absorbing structure is a rigid wall, and the rigid wall, together with the cavity 15, further improves the sound absorption and sound-absorbing effect.

[0046] In some embodiments of the present invention, the materials used to prepare the sound-absorbing unit 1 include shape memory alloys and shape memory polymers.

[0047] In this embodiment, the material used to prepare the sound-absorbing unit 1 includes shape memory material. This configuration allows the sound-absorbing material to be stretched to create gaps between the sound-absorbing units 1. Deformation stimulation is then applied to the sound-absorbing structure to restore it to a gapless state where the sidewalls 12 are tightly attached, thereby allowing for repeated adjustment of the noise reduction frequency and effect.

[0048] It is understandable that shape memory materials can be shape memory alloys, shape memory polymers, or shape memory composite materials.

[0049] In some embodiments of the present invention, shape memory materials are prepared by 4D printing technology.

[0050] In this embodiment, 4D printing technology has the following advantages: physical objects can be transformed from one form to another, providing maximum product design freedom; driving, logic, and sensing capabilities can be embedded in printed parts without additional time and cost; customized production can be carried out in the same batch of products; the products have strong designability and the surface precision of the products can be adjusted.

[0051] In some embodiments of the present invention, the sound-absorbing structure includes a sound-absorbing hole 14 penetrating the cylindrical surface 11.

[0052] In this embodiment, the apertures of the sound-absorbing holes 14 are all on the sub-millimeter scale. The sound-absorbing holes 14 increase the noise spectrum passing through them, thereby reducing the audible sound components in the spectrum and thus reducing noise interference and harm to people.

[0053] In some embodiments of the present invention, the noise-absorbing structure includes a noise-absorbing membrane disposed on the cylindrical surface 11, the noise-absorbing membrane being soft and having an uneven surface.

[0054] In this embodiment, the sound-absorbing structure can be a sound-absorbing membrane. The uneven surface of the sound-absorbing membrane shifts the absorption peak of the resonant structure to lower frequencies, which is beneficial for low-frequency absorption. Secondly, when mid-to-high frequency sounds are incident from different angles, the sound waves have the opportunity to undergo multiple reflections on the membrane surface, greatly increasing the chance of the sound waves passing through the airflow barrier membrane. This avoids the strong reflection of mid-to-high frequency sounds by a flat airflow barrier membrane, allowing most mid-to-high frequency sounds to smoothly enter the structure and be absorbed, thus achieving absorption of mid, high, and low frequency sounds.

[0055] In some embodiments of the present invention, the sound-absorbing unit 1 includes a quadrangular prism structure.

[0056] In this embodiment, the sound-absorbing unit 1 is a quadrangular prism, which makes it easier to splice together to form an overall sound-absorbing structure. In addition, the quadrangular prism sound-absorbing unit 1 forms quadrilateral gaps, making it easier to control the size of the quadrilateral gaps.

[0057] Of course, the sound-absorbing unit 1 can also be a triangular prism, a pentagonal prism, or a hexagonal prism.

[0058] In some embodiments of the present invention, the cavity 15 of the sound-absorbing unit 1 is provided with a partition 13, which divides the cavity 15 into two parts, and the partition 13 is provided with a sound-absorbing structure.

[0059] In this embodiment, the sound-absorbing structure of the cylindrical surface 11, the sound-absorbing structure of the partition 13, and the two-part cavity 15 can further enhance the sound absorption effect.

[0060] In some embodiments of the present invention, the diameter of the sound-absorbing hole 14 is 0.25 to 0.35 mm;

[0061] The cavity 15 of the sound-absorbing unit 1 is provided with a partition 13, which divides the cavity 15 into two parts. The partition 13 is provided with a sound-absorbing structure. The distance between the cylindrical surface 11 with the sound-absorbing structure and the partition 13 is 25-35mm, and the distance between the partition 13 and the cylindrical surface 11 without the sound-absorbing structure is 15-25mm.

[0062] In this embodiment, as Figure 6 As shown, with the above parameters, the sound-absorbing bands with a sound absorption coefficient exceeding 0.5 range from 750Hz to 3500Hz.

[0063] This invention also provides an application of the sound-absorbing structure based on any one of the above-described embodiments, including:

[0064] Cover the target with a sound-absorbing structure and stretch the sound-absorbing structure according to the usage requirements;

[0065] Tensile sound-absorbing structure, including:

[0066] Surface-stretched sound-absorbing structure perpendicular to the sound-absorbing structure;

[0067] And / or,

[0068] Surface-stretched sound-absorbing structure parallel to the sound-absorbing structure.

[0069] In this embodiment, a sound-absorbing structure is used to cover the target to isolate sound. The sound-absorbing structure can be planar or curved, and can be fully enclosed or semi-enclosed. When stretching the sound-absorbing structure, the tension can be applied parallel to the layer containing the sound-absorbing structure; if the boundary of the sound-absorbing structure is fixed and it is not possible to apply tension parallel to the layer containing the sound-absorbing structure, tension can be applied perpendicular to the surface of the sound-absorbing structure to create gaps.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A controllable sound-absorbing structure based on shape memory negative Poisson's ratio material, characterized in that, The structure includes a layered structure formed by multiple sound-absorbing units (1), the material of which includes shape memory negative Poisson's ratio material, the sound-absorbing unit (1) is a prism structure, and there is only one edge between each two adjacent sound-absorbing units (1) for mutual rotational connection, the prism structure includes two prism faces (11) and multiple sidewalls (12), the prism structure forms a cavity (15), the two prism faces (11) of the sound-absorbing unit (1) form the layer of the layered structure, and the prism faces (11) of the sound-absorbing unit (1) facing the same direction are provided with a sound-absorbing structure; When the sound-absorbing structure is in a sound-absorbing state, the sidewalls (12) of adjacent sound-absorbing units (1) are in contact with each other. When the sound-absorbing structure is stimulated by the outside, it stretches the sound-absorbing structure and causes the sound-absorbing units (1) to rotate relative to each other, forming a gap between the sound-absorbing units (1). The sound-absorbing structure is in a sound-passing state. When stimulated by the outside again, the sound-absorbing structure can be restored to a sound-absorbing state to achieve controllable deformation. By controlling the opening and closing of the gap, the sound-absorbing structure can be controlled to pass or absorb sound. By controlling the size of the gap, the sound absorption effect and bandwidth of the sound-absorbing structure can be controlled. The sound-absorbing unit (1) includes a quadrangular prism structure; The materials used to prepare the sound-absorbing unit (1) include shape memory alloys and shape memory polymers; The noise reduction structure includes a noise reduction membrane disposed on the cylindrical surface (11), the noise reduction membrane being soft and having an uneven surface.

2. The sound-absorbing structure according to claim 1, characterized in that, The shape memory polymer is prepared using 4D printing technology.

3. The sound-absorbing structure according to claim 1, characterized in that, The sound-absorbing structure includes a sound-absorbing hole (14) penetrating the cylindrical surface (11).

4. The sound-absorbing structure according to claim 1, characterized in that, The cavity (15) of the sound-absorbing unit (1) is provided with a partition (13), which divides the cavity (15) into two parts, and the partition (13) is provided with the sound-absorbing structure.

5. The sound-absorbing structure according to claim 3, characterized in that, The diameter of the sound-absorbing hole (14) is 0.25~0.35mm; The cavity (15) of the sound-absorbing unit (1) is provided with a partition (13), which divides the cavity (15) into two parts. The partition (13) is provided with the sound-absorbing structure. The distance between the cylindrical surface (11) with the sound-absorbing structure and the partition (13) is 25~35mm. The distance between the partition (13) and the cylindrical surface (11) without the sound-absorbing structure is 15~25mm.

6. An application of the sound-absorbing structure based on any one of claims 1-5, characterized in that, include: Cover the target with the sound-absorbing structure and stretch the sound-absorbing structure according to the usage requirements; The stretching of the sound-absorbing structure includes: The sound-absorbing structure is stretched perpendicular to its surface; And / or, The sound-absorbing structure is stretched parallel to its surface.

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