A noise reduction composite aluminum plate
Through multi-level structural design and material combination, aluminum plates achieve coordinated control of high-frequency, mid-frequency and low-frequency noise, solving the problem of insufficient noise reduction capability of existing aluminum plates and enhancing structural stability and noise reduction effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU CAIFA ALUMINUM
- Filing Date
- 2025-07-23
- Publication Date
- 2026-06-09
AI Technical Summary
Existing aluminum plates have limited noise reduction capabilities when facing noise problems, especially in terms of the coordinated control of high-frequency, mid-frequency and low-frequency noise. Furthermore, existing designs suffer from insufficient structural stability and complex connection methods.
The system employs a multi-level structural design, including a cover plate with conical through holes, closed-cell foam cavities, trapezoidal wave support skeleton, honeycomb panels, and gradient density sound insulation cotton. Combined with viscoelastic damping adhesive, it forms a full-band noise reduction system. Noise suppression is achieved through Bragg scattering, interference cancellation, and gradient impedance matching, while structural stability is ensured through snap-fit components and bolt connections.
It achieves coordinated control of high-frequency, mid-frequency and low-frequency noise, enhances the stability of the structure and the noise reduction effect, effectively suppresses the propagation of noise and vibration, and improves the overall noise reduction performance.
Smart Images
Figure CN224338502U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of sheet metal technology, specifically to a noise-reducing composite aluminum sheet. Background Technology
[0002] In modern industry and construction, noise pollution has become a critical issue that urgently needs to be addressed. With the rapid advancement of urbanization and the continuous expansion of industrial production, noise generated by machinery operation and transportation seriously disrupts people's living and working environments, negatively impacting health and work efficiency. Aluminum sheets, as a commonly used building and industrial material, are widely used in many fields due to their good mechanical properties, corrosion resistance, and light weight. However, ordinary aluminum sheets have limited noise reduction capabilities and struggle to meet increasingly stringent noise reduction requirements.
[0003] In existing technologies, vibration and noise suppression mainly employs single-structure or material designs, such as adding sound-absorbing cotton, damping coatings, or locally reinforced structures to achieve noise reduction. However, such solutions generally suffer from the following technical bottlenecks: First, traditional sound-absorbing materials have high absorption efficiency for high-frequency noise but limited ability to block low-frequency noise, making it difficult to achieve coordinated control of noise across a wide frequency range; second, single damping structures are prone to local resonance under complex vibration excitation, leading to reduced energy dissipation efficiency; third, existing noise reduction components are mostly connected to the substrate structure by welding or bolting, resulting in complex installation processes, insufficient sealing, and difficulty in adapting to structural deformation under dynamic loads.
[0004] Furthermore, research indicates that improving sound wave scattering and energy conversion efficiency through structural optimization is a crucial approach to overcoming the limitations of existing noise reduction technologies. For instance, periodic phonon crystal structures can suppress sound wave propagation in specific frequency bands through the Bragg scattering effect, while the synergistic effect of multi-level damping units can enhance the dissipation of vibrational energy. However, existing technologies often suffer from problems such as discontinuous acoustic impedance matching and a single energy dissipation path, leading to easy reflection and transmission of sound waves during propagation and reducing the overall noise reduction effect. In addition, existing designs lack synergistic optimization of the stiffness of the supporting frame and the distribution of sound-absorbing materials to meet the structural stability requirements under complex working conditions, making it difficult to achieve efficient sound absorption and insulation performance while ensuring structural strength.
[0005] Therefore, a noise-reducing composite aluminum plate is proposed to address the current shortcomings. Utility Model Content
[0006] In order to solve the problems of the prior art, this utility model provides a noise-reducing composite aluminum plate.
[0007] The technical problem to be solved by this utility model is to overcome the defects of the above-mentioned technology and provide a noise-reducing composite aluminum plate.
[0008] To solve the above-mentioned technical problems, the technical solution provided by this utility model is a noise-reducing composite aluminum plate, including a substrate and a cover plate;
[0009] A groove is formed on the upper side of the substrate, and multiple microgrooves are arrayed on the bottom wall of the groove. The microgrooves are filled with viscoelastic damping adhesive to form a vibration dissipation layer.
[0010] The groove is provided with a support frame with a continuous trapezoidal wave cross section. A honeycomb panel is embedded in the trapezoidal wave trough of the support frame. The cavity of the honeycomb panel is filled with gradient density sound insulation cotton, and the density of the gradient density sound insulation cotton increases along the incident direction of the sound wave.
[0011] The cover plate is fixed to the base plate by a snap-fit assembly. The inner side of the cover plate is provided with a connecting seat that engages with the trapezoidal crest of the support frame. The base plate is provided with bolts that connect to the connecting seat. The cavity between the base plate and the cover plate is filled with closed-cell polyurethane foam.
[0012] The outer surface of the cover plate is provided with tapered through holes distributed in a gradient.
[0013] As an improvement, the microgroove is in the shape of a regular hexagon.
[0014] As an improvement, the gradient density sound insulation cotton includes a low-density layer, a medium-density layer and a high-density layer sequentially from the sound wave incident side to the substrate side.
[0015] As an improvement, the low-density layer is made of EPDM foamed open-cell material with a porosity of 85%; the medium-density layer is made of silica aerogel particles with a porosity of 60% and a particle size of 0.5-2mm; and the high-density layer is made of glass fiber and polyurethane composite material with a porosity of 30%.
[0016] As an improvement, the flared end of the tapered through hole faces the external sound source, and the angle between the axis of the tapered through hole and the surface of the cover plate is 75°.
[0017] As an improvement, the snap-fit assembly includes snap-fit slots at both ends of the substrate and elastic snap-fit blocks on both sides of the cover plate. The bottom of the snap-fit slot is provided with a silicone rubber sealing gasket with a compression rate of 20%-30%, and the elastic snap-fit blocks form an interference fit with the snap-fit slot.
[0018] As an improvement, the trapezoidal wave structure of the supporting frame has an inclination angle of 55°-65°.
[0019] As an improvement, the aperture gradient distribution of the tapered through hole satisfies the following: the aperture density in the central region of the cover plate is 60-80 holes / dm², and the aperture density in the edge region is 30-50 holes / dm².
[0020] The advantages of this utility model compared with the prior art are as follows:
[0021] Through a multi-level structural design consisting of a cover plate with conical through-hole array, closed-cell foam cavity, trapezoidal wave support skeleton, honeycomb panel, gradient density sound insulation cotton, and viscoelastic damping adhesive, a full-band noise reduction system is formed, encompassing sound wave capture, scattering dissipation, layered absorption, and vibration suppression. Utilizing physical effects such as Bragg scattering, interference cancellation, and gradient impedance matching, synergistic control of high-frequency, mid-frequency, and low-frequency noise is achieved, effectively suppressing noise.
[0022] By setting gradient-distributed tapered through-holes on the outer surface of the cover plate, with the flared ends facing the sound source, sound waves can be effectively captured and guided into the plate. Sound waves are incident at a non-perpendicular angle within the tapered through-holes, resulting in multiple reflections, scattering, and friction, thus extending the propagation path and dissipating some of the acoustic energy as heat. The high-density hole region in the center achieves concentrated capture and dissipation of high acoustic energy, while the low-density hole region at the edges maintains basic sound attenuation while reducing structural weakening and sound wave diffraction. The decreasing hole density creates an acoustic impedance gradient, allowing sound wave energy to attenuate smoothly and reducing abrupt reflections.
[0023] The bottom wall of the groove on the upper side of the substrate is arrayed with regular hexagonal microgrooves, which are filled with viscoelastic damping adhesive to form a continuous vibration dissipation layer. When the substrate is subjected to vibration, the microgrooves constrain the damping adhesive to mainly undergo shear deformation, and the internal friction between its molecular chains converts mechanical vibration energy into heat energy for dissipation. The array of regular hexagonal microgrooves enables the damping adhesive to form multiple "micro-dampers" working in concert, effectively suppressing the bending vibration and local resonance of the substrate. At the same time, the elastic deformation of the honeycomb panel absorbs some of the vibration energy, reducing the resonance amplitude of the supporting skeleton.
[0024] The substrate and cover plate are connected by snap-fit components and bolts, forming a tight mechanical interlock and a sealed cavity. The cavity is filled with closed-cell polyurethane foam, which serves both as a buffer and enhances structural stability. The supporting frame is fixedly connected to the substrate, improving the overall rigidity of the substrate, resisting deformation, and providing stable support for the internal noise reduction structure. This ensures that the entire noise reduction composite aluminum plate structure remains stable under the impact of sound waves or external forces, preventing loosening or displacement. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the structure of a noise-reducing composite aluminum plate according to this utility model. Figure 1 .
[0026] Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle.
[0027] Figure 3 This is a schematic diagram of the structure of a noise-reducing composite aluminum plate according to this utility model. Figure 2 .
[0028] Figure 4 This is a side view of a noise-reducing composite aluminum plate according to this utility model.
[0029] Figure 5 yes Figure 4 A magnified view of a section at point B in the middle.
[0030] Figure 6 This is a schematic diagram of the substrate portion in a noise-reducing composite aluminum plate according to this utility model.
[0031] Figure 7 yes Figure 6 A magnified view of a section at point C.
[0032] Figure 8 This is a schematic diagram of the cover plate portion of a noise-reducing composite aluminum plate according to this utility model.
[0033] Figure 9 yes Figure 8 A magnified view of a section at point D.
[0034] Figure 10 This is a schematic diagram of the microgroove structure in a noise-reducing composite aluminum plate according to this utility model.
[0035] Figure 11 This is a schematic diagram of the conical through hole in a noise-reducing composite aluminum plate according to this utility model.
[0036] Figure 12 This is a schematic diagram of the supporting frame structure in a noise-reducing composite aluminum plate according to this utility model.
[0037] Figure 13 This is a schematic diagram of the structure of gradient density sound insulation cotton in a noise-reducing composite aluminum plate according to this utility model.
[0038] As shown in the figure:
[0039] 1. Substrate; 101. Groove; 102. Microgroove; 103. Slot;
[0040] 2. Cover plate; 201. Elastic locking block;
[0041] 3. Viscoelastic damping adhesive; 4. Support frame; 5. Honeycomb panel;
[0042] 6. Gradient density sound insulation cotton; 601. Low density layer; 602. Medium density layer; 603. High density layer;
[0043] 7. Connector; 8. Bolt; 9. Closed-cell polyurethane foam; 10. Tapered through hole; 11. Silicone rubber gasket. Detailed Implementation
[0044] To make the objectives, technical solutions, and advantages of the utility model embodiments clearer, the technical solutions of the utility model embodiments will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. The components of the utility model embodiments described and shown in the accompanying drawings can typically be arranged and designed in various different configurations.
[0045] In the description of the embodiments of the utility model, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use, they are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the utility model. Furthermore, terms such as "first," "second," and "third" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0046] Furthermore, the use of terms such as "horizontal," "vertical," and "sag" does not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0047] In the description of the utility model embodiments, "a plurality of" means at least two.
[0048] In the description of the embodiments of the utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the utility model according to the specific circumstances.
[0049] As shown in the accompanying drawings, a noise-reducing composite aluminum plate includes a substrate 1 and a cover plate 2. In this embodiment, both the substrate 1 and the cover plate 2 are made of aluminum plates.
[0050] A groove 101 is formed on the upper side of the substrate 1. Multiple micro-grooves 102 are arrayed on the bottom wall of the groove 101. The micro-grooves 102 are regular hexagonal. The spacing between adjacent micro-grooves 102 is uniform to form a regular honeycomb pit array. In this embodiment, the coverage of the micro-grooves 102 reaches 60%-80% of the bottom wall area of the groove 101 of the substrate 1.
[0051] The microgroove 102 is filled with viscoelastic damping adhesive 3 to form a vibration dissipation layer. Specifically, the viscoelastic damping adhesive 3 is a polyurethane damping adhesive, which is tightly bonded to the microgroove 102, and its surface is flush with the bottom wall of the groove 101 to form a continuous vibration dissipation layer.
[0052] When the substrate 1 is subjected to external excitation (such as mechanical vibration or vibration of the plate caused by sound waves), the viscoelastic damping adhesive 3 undergoes shear deformation, and the internal friction between its molecular chains converts mechanical energy into heat energy, realizing the energy dissipation of "vibration-heat energy".
[0053] The array structure of regular hexagonal microgrooves enables the viscoelastic damping adhesive 3 to form multiple independent yet synergistic vibration damping units. The viscoelastic damping adhesive 3 in each microgroove 102 can be regarded as a "micro damper" to jointly suppress the bending vibration and local resonance of the substrate 1.
[0054] Meanwhile, the combination of groove 101 and microgroove 102 on substrate 1 forms a composite structure of "rigid matrix-flexible damping". The substrate 1 provides rigid support to prevent the viscoelastic damping adhesive 3 from failing under large deformation. The microgroove 102 constrains the deformation direction of the viscoelastic damping adhesive 3, so that it mainly produces shear deformation (rather than tension / compression), maximizing the damping loss efficiency.
[0055] The groove 101 is provided with a support frame 4 with a cross-section of continuous trapezoidal wave. The support frame 4 is fixedly connected to the base plate 1. In this embodiment, the support frame 4 is made of aluminum alloy and is fixedly connected to the base plate 1 by welding.
[0056] The trapezoidal wave-shaped support frame 4 can significantly improve the overall rigidity of the substrate 1, enabling the substrate 1 to effectively resist deformation when subjected to sound wave impact, thereby ensuring the stability and integrity of the noise reduction composite aluminum plate, providing a stable support foundation for other noise reduction structures (such as honeycomb panels 5 and sound insulation cotton 6), and helping to give full play to the noise reduction function of each part.
[0057] The supporting frame 4 consists of alternating peaks and troughs, forming a periodic trapezoidal concave-convex structure. The periodically arranged trapezoidal waves form a "phonon crystal"-like structure, which suppresses the propagation of sound waves in specific frequency bands through the Bragg scattering effect, forming band-stop filtering characteristics. At the same time, the continuous waveform reduces structural seams, avoids sound leakage, and improves the overall sound insulation.
[0058] Furthermore, the trapezoidal wave structure supporting the frame 4 has an inclination angle of 55°-65°. When the sound wave is incident on the trapezoidal wave surface, it is obliquely reflected due to the inclination angle. The phase difference of the reflected sound at different wave peaks and valleys leads to interference cancellation. At the same time, the sound wave diffraction effect at the corner of the trapezoid causes the sound energy to scatter in multiple directions, increasing the probability of contact with the sound insulation cotton 6.
[0059] Moreover, compared to a vertical plane (90°), the tilt setting can increase the number of sound wave reflections and extend the dissipation time.
[0060] A honeycomb panel 5 is embedded in the trapezoidal trough of the support frame 4. The outer dimensions of the honeycomb panel 5 match the trapezoidal trough of the support frame 4. After the edge of the honeycomb panel 5 is embedded in the trapezoidal trough of the support frame 4, it is bonded and fixed with structural adhesive (such as silicone adhesive) to ensure a tight fit with the bottom and sidewall of the trough of the support frame 4.
[0061] In this embodiment, the honeycomb panel 5 is made of aluminum alloy, and the thickness of the honeycomb panel 5 is 80%-90% of the depth of the trough of the supporting skeleton 4. The shape of the honeycomb holes in the honeycomb panel 5 can be hexagonal, rectangular or circular. In this embodiment, the honeycomb holes in the honeycomb panel 5 are hexagonal to achieve close coverage and uniform stress.
[0062] During implementation, the honeycomb panel 5 and the supporting frame 4 form a three-dimensional grid-like composite structure. The periodic arrangement of the honeycomb holes in the honeycomb panel 5 can produce "Brag scattering" of sound waves. When the wavelength of the sound wave is close to the size of the honeycomb holes, coherent scattering can be triggered, and the sound energy will be dispersed in multiple directions, reducing direct transmission.
[0063] Meanwhile, as sound waves are reflected multiple times within the honeycomb pores, the friction between the pore walls and the air converts sound energy into heat energy.
[0064] In addition, the honeycomb wall of the honeycomb panel 5 has a certain elasticity. When the vibration of the substrate 1 is transmitted to the trough of the support frame 4, the honeycomb panel 5 absorbs part of the vibration energy through out-of-plane elastic deformation, thereby reducing the resonance amplitude of the support frame 4.
[0065] The cavity of the honeycomb panel 5 is filled with gradient density sound insulation cotton 6, and the density of the gradient density sound insulation cotton 6 increases along the direction of sound wave incidence.
[0066] The gradient density sound insulation cotton 6 includes a low-density layer 601, a medium-density layer 602 and a high-density layer 603 sequentially from the sound wave incident side to the substrate 1 side.
[0067] Specifically, the low-density layer 601 is made of EPDM foamed open-cell material with a porosity of 85%, forming a loose and porous structure;
[0068] The low-density layer 601 absorbs high-frequency sound waves. Since high-frequency sound waves have short wavelengths, after the sound waves enter the porous structure, the porous structure dissipates the sound energy through viscous friction and thermal conduction. At the same time, the high porosity provides more sound wave entry paths, thereby improving the high-frequency absorption efficiency.
[0069] Meanwhile, as the first layer for sound wave incidence, the low-density layer 601 reduces sound wave reflection and allows sound waves to enter, laying the foundation for the synergistic sound absorption of subsequent layers.
[0070] The medium-density layer 602 is made of silica aerogel particles with a porosity of 60% and a particle size of 0.5-2mm. The nanoscale multi-level pore structure formed between the gel particles increases the length of the sound wave propagation path, and multiple scattering interfaces are formed between the particles. The sound waves are reflected multiple times between the particles, which enhances the absorption of mid-frequency sound energy.
[0071] The high-density layer 603 is made of a glass fiber and polyurethane composite material with a porosity of 30%. The glass fiber and polyurethane composite material has a low porosity and a relatively dense structure. Since low-frequency sound waves have long wavelengths and strong penetrating power, the high-density layer 603, due to its high density and dense structure, can effectively block the propagation of low-frequency sound waves, making it difficult for low-frequency sound waves to penetrate, thereby reducing the transmission of low-frequency noise and achieving the blocking of low-frequency noise.
[0072] In practice, sound waves enter the gradient density sound insulation cotton 6 through the regular hexagonal holes of the honeycomb panel 5. First, the honeycomb holes in the honeycomb panel 5 initially scatter the sound waves and change their propagation direction. Then, the gradient density sound insulation cotton 6 absorbs the sound waves layer by layer according to the frequency, so that the sound wave energy gradually decreases with depth.
[0073] The cover plate 2 is fixed to the substrate 1 by a snap-fit assembly. The snap-fit assembly includes a snap-fit groove 103 at both ends of the substrate 1 and elastic snap-fit blocks 201 on both sides of the cover plate 2. The bottom of the snap-fit groove 103 is provided with a silicone rubber sealing gasket 11 with a compression rate of 20%-30%. The elastic snap-fit blocks 201 and the snap-fit groove 103 form an interference fit. The elastic snap-fit blocks 201 are inserted into the snap-fit groove 103 to form an interference fit and achieve initial fixation. The silicone rubber sealing gasket 11 at the bottom of the snap-fit groove 103 fills the gap after being squeezed, enhancing the sealing and fixing effect.
[0074] The inner side of the cover plate 2 is provided with a connecting seat 7 that engages with the trapezoidal crest of the support frame 4.
[0075] In this embodiment, the end of the connecting seat 7 on the inner side of the cover plate 2 is designed as a trapezoidal groove. The trapezoidal crest of the supporting frame 4 is embedded in the trapezoidal groove of the connecting seat 7, and its crest side is tightly fitted with the side wall of the trapezoidal groove, forming a mechanical interlock with the crest of the supporting frame 4. This further enhances the firmness and vibration resistance of the connection between the cover plate 2 and the substrate 1, so that the cover plate 2 and the substrate 1 can withstand a certain mechanical stress, preventing loosening or displacement under the action of sound wave impact or external force. At the same time, a sealed cavity is formed between the interlocking cover plate 2 and the substrate 1.
[0076] The cavity between the substrate 1 and the cover plate 2 is filled with closed-cell polyurethane foam 9, which has a large number of independent and closed pores. When sound waves pass through the substrate 1 or the cover plate 2 and enter the cavity, they encounter the closed-cell polyurethane foam 9. The sound waves are repeatedly reflected and propagated in the closed pores. The friction and viscous resistance between the air and the pore walls convert the sound wave energy into heat energy and dissipate it, thereby reducing the intensity of the sound waves and achieving the sound absorption and noise reduction effect.
[0077] A bolt 8 is provided on the substrate 1 to connect with the connecting seat 7, so as to realize the fixed connection between the cover plate 2 and the substrate 1. Moreover, the setting of the bolt 8 can keep the connecting seat 7 and the trapezoidal crest of the support frame 4 in a tight engagement state, ensuring that the internal honeycomb panel 5, sound insulation cotton 6 and closed-cell polyurethane foam 9 and other noise reduction structures are always in a stable working state, giving full play to their sound absorption, sound insulation and vibration reduction functions, and maintaining a good noise reduction effect.
[0078] The outer surface of the cover plate 2 is provided with tapered through holes 10 distributed in a gradient. The flared end of the tapered through holes 10 faces the external sound source, and the angle between the axis of the tapered through holes 10 and the surface of the cover plate 2 is 75°.
[0079] The flared end of the tapered through-hole 10 faces the external sound source, which can effectively capture and guide the sound waves, increase the probability of the sound waves entering the tapered through-hole 10, and improve the absorption efficiency of the sound waves.
[0080] Meanwhile, the angle between the axis of the conical through-hole 10 and the surface of the cover plate 2 is 75°, causing the sound wave to be incident in a non-perpendicular direction within the conical through-hole 10, resulting in multiple reflections and scatterings. The complex reflection path of the sound wave within the conical through-hole 10 can increase the propagation distance of the sound wave, thereby increasing the dissipation of sound wave energy and reducing the intensity of the sound wave. In addition, the inner wall of the conical through-hole 10 can rub against the sound wave, converting the sound wave energy into heat energy, further absorbing the sound wave energy.
[0081] Specifically, the aperture gradient distribution of the tapered through hole 10 satisfies the following: the aperture density in the central region of the cover plate 2 is 60-80 holes / dm², and the aperture density in the edge region is 30-50 holes / dm².
[0082] During implementation, when noise is incident perpendicularly, the sound wave energy exhibits a distribution characteristic of central concentration and edge attenuation on the plate surface.
[0083] The high-density aperture region is located in the central area of the cover plate 2, and the high-density aperture region is concentrated in the sound pressure peak area, forming a dense resonant cavity array to maximize the capture and consumption of high sound energy.
[0084] The low-density perforated area is located at the edge of the cover plate 2. This low-density perforated area is matched with the edge sound pressure attenuation, which maintains the basic sound absorption while avoiding structural weakening caused by excessive perforation. Moreover, the reduced perforation density in the edge area can reduce the diffraction of sound waves at the plate edge and block the "bypass leakage" path of sound energy.
[0085] At the same time, the pore density decreases from the center to the edge, forming a continuous acoustic impedance gradient, which allows the sound wave to undergo a smooth energy attenuation process when it is transmitted on the plate surface, reducing abrupt reflections.
[0086] In specific implementation of this utility model:
[0087] 1) Acoustic wave capture and initial dissipation (surface of cover plate 2):
[0088] External sound waves first reach the outer surface of the cover plate 2. The flared end of the conical through hole 10 faces the external sound source, effectively capturing and guiding the sound waves into the hole. After the sound waves enter the conical through hole 10 at a non-perpendicular angle of 75°, they undergo multiple reflections, scattering, and friction on the inner wall of the hole, extending the sound wave propagation path and causing some of the sound energy to be converted into heat energy and consumed.
[0089] Meanwhile, the high-density pore region at the center maximizes the capture and dissipation of high acoustic energy; the low-density pore region at the edges maintains basic sound attenuation while reducing structural weakening and sound wave diffraction. The decreasing pore density creates an acoustic impedance gradient, allowing sound wave energy to attenuate smoothly as it is transmitted through cover plate 2, reducing abrupt reflections.
[0090] 2) Cavity sound absorption and sealing (substrate 1 - cover plate 2 cavity):
[0091] The residual sound waves that penetrate the conical through-hole 10 enter the sealed cavity between the substrate 1 and the cover plate 2, and the sealed cavity is filled with closed-cell polyurethane foam 9.
[0092] Sound waves are repeatedly reflected and propagated within the independent, closed pores of the closed-cell polyurethane foam 9. The friction and viscous resistance between the air and the pore walls convert the sound wave energy into heat energy, which is then dissipated. At the same time, the closed-cell polyurethane foam 9 also serves as a buffer and auxiliary seal.
[0093] 3) Structural guidance and core noise reduction (supporting frame 4, honeycomb panel 5, gradient sound insulation cotton 6):
[0094] After the residual sound waves pass through the closed-cell polyurethane foam 9, they encounter the trapezoidal wave surface of the supporting skeleton 4.
[0095] 3.1 The supporting framework 4 (with a cross-section exhibiting a continuous trapezoidal wave pattern) forms a structure similar to a "phonon crystal":
[0096] Bragg scattering: Its periodic trapezoidal concave-convex structure (alternating crests and troughs) causes Bragg scattering of sound waves in a specific frequency band, inhibiting their propagation.
[0097] Oblique reflection and destructive interference: The tilt angle of the trapezoidal wave structure (55°-65°) causes the incident sound wave to be obliquely reflected. At the same time, the reflected sound waves from different wave crests and troughs have a phase difference due to the path difference, resulting in destructive interference.
[0098] Diffraction and scattering: Sound wave diffraction is induced at the trapezoidal corners, and sound energy is scattered in multiple directions, increasing the probability of subsequent contact with sound-absorbing materials.
[0099] Extending the dissipation path: Compared to a vertical plane, the tilt angle increases the number of sound wave reflections and the dissipation time within the structure.
[0100] The scattered sound waves enter the honeycomb panel 5 embedded in the trapezoidal trough of the supporting skeleton 4.
[0101] 3.2 Honeycomb panel 5 (internal honeycomb holes are regular hexagons):
[0102] Bragg scattering: The periodic arrangement of the honeycomb pores coherently scatters sound waves of a specific wavelength (close to the pore size), causing the sound energy to disperse in multiple directions and reducing direct transmission.
[0103] Energy dissipation due to friction between the pore walls: Sound waves are reflected multiple times within the honeycomb pores, and the friction between the pore walls and the air converts some of the sound energy into heat energy.
[0104] Structural guidance: The honeycomb holes guide the sound waves to the gradient density sound insulation cotton 6 filling the sealed cavity.
[0105] 3.3 Gradient density sound insulation cotton 6 (from the sound wave incident side to the substrate 1 side: low density layer 601, medium density layer 602, high density layer 603):
[0106] Layered absorption:
[0107] Low-density layer 601 (high-porosity EPDM foamed open-cell): Low flow resistance allows for efficient sound wave entry, and the loose porous structure primarily absorbs high-frequency sound waves through viscous friction and thermal conduction.
[0108] Medium-density layer 602 (silica aerogel particles): The nanoscale multi-level pores formed between particles increase the sound wave propagation path, and the multiple scattering at the particle interface enhances the absorption of mid-frequency sound energy.
[0109] High-density layer 603 (glass fiber / polyurethane composite): The relatively dense structure provides high flow resistance, mainly blocking the propagation of low-frequency sound waves with strong penetrating power.
[0110] Synergistic energy dissipation: Sound waves undergo an impedance transition "from sparse to dense" in gradient density sound insulation cotton 6, and the energy decreases layer by layer with depth.
[0111] 4) Vibration suppression and energy conversion (substrate 1 and viscoelastic damping adhesive 3):
[0112] The sound wave energy that is partially penetrated or not completely absorbed may cause the substrate 1 to vibrate (either due to sound wave impact or transmission through the structure).
[0113] The support frame 4 significantly improves the overall rigidity of the substrate 1, effectively resists deformation, ensures structural stability, provides solid support for the internal noise reduction structure, and suppresses large-amplitude vibrations.
[0114] The bottom wall of the groove 101 on the upper side of the substrate 1 is arrayed with regular hexagonal microgrooves 102, and the microgrooves 102 are filled with viscoelastic damping adhesive 3 to form a continuous vibration dissipation layer.
[0115] When substrate 1 vibrates:
[0116] The microgroove 102 constrains the viscoelastic damping adhesive 3, which mainly generates shear deformation. Under shear deformation, the internal friction between the molecular chains of the viscoelastic damping adhesive 3 efficiently converts mechanical vibration energy into heat energy dissipation.
[0117] The array of regular hexagonal microgrooves 102 enables the viscoelastic damping adhesive 3 to form multiple "micro dampers" that work together to suppress the bending vibration and local resonance of the substrate 1.
[0118] The honeycomb wall of the honeycomb panel 5 has a certain elasticity. When the vibration is transmitted to the trough of the support frame 4, the honeycomb panel 5 absorbs part of the vibration energy through out-of-plane elastic deformation, thereby reducing the resonance amplitude of the support frame 4.
[0119] 5) Structural stability and sealing assurance (connection and fixation):
[0120] The cover plate 2 is initially fixed by an interference fit between the elastic locking block 201 and the locking grooves 103 at both ends of the base plate 1. The silicone rubber sealing gasket 11 at the bottom of the locking groove 103 fills the gap after being compressed, enhancing the sealing and fixation.
[0121] The connecting seat 7 on the inner side of the cover plate 2 is tightly engaged with the trapezoidal crest of the support frame 4, forming a mechanical interlock, which significantly enhances the firmness, vibration resistance and cavity sealing of the connection.
[0122] Bolt 8 passes through the base plate 1 and connects to the connector 7, ensuring that the connector 7 and the crest of the support frame 4 maintain a tight engagement, and finally fixes the cover plate 2 to the base plate 1. This ensures that the internal honeycomb panel 5, sound insulation cotton 6, closed-cell polyurethane foam 9 and other structures are always in a stable working state, maintaining long-term effective noise reduction performance.
[0123] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.
Claims
1. A noise-reducing composite aluminum plate, characterized in that: Includes a substrate (1) and a cover plate (2); The substrate (1) has a groove (101) on its upper side. The bottom wall of the groove (101) is arrayed with multiple micro-grooves (102). The micro-grooves (102) are filled with viscoelastic damping glue (3) to form a vibration dissipation layer. The groove (101) is provided with a support frame (4) with a continuous trapezoidal wave cross section. A honeycomb plate (5) is embedded in the trapezoidal wave valley of the support frame (4). The cavity of the honeycomb plate (5) is filled with gradient density sound insulation cotton (6). The density of the gradient density sound insulation cotton (6) increases along the direction of sound wave incidence. The cover plate (2) is fixed to the base plate (1) by a snap-fit assembly. The inner side of the cover plate (2) is provided with a connecting seat (7) that engages with the trapezoidal crest of the support frame (4). The base plate (1) is provided with a bolt (8) that is connected to the connecting seat (7). The cavity between the base plate (1) and the cover plate (2) is filled with closed-cell polyurethane foam (9). The outer surface of the cover plate (2) is provided with tapered through holes (10) distributed in a gradient.
2. The noise-reducing composite aluminum plate according to claim 1, characterized in that: The microgroove (102) is in the shape of a regular hexagon.
3. The noise-reducing composite aluminum plate according to claim 1, characterized in that: The gradient density sound insulation cotton (6) includes a low density layer (601), a medium density layer (602) and a high density layer (603) from the sound wave incident side to the substrate (1) side.
4. The noise-reducing composite aluminum plate according to claim 3, characterized in that: The low-density layer (601) is made of EPDM foamed open-cell material with a porosity of 85%; The medium-density layer (602) is made of silica aerogel particles with a porosity of 60% and a particle size of 0.5-2 mm; The high-density layer (603) is made of a glass fiber and polyurethane composite material with a porosity of 30%.
5. The noise-reducing composite aluminum plate according to claim 1, characterized in that: The flared end of the tapered through hole (10) faces the external sound source, and the angle between the axis of the tapered through hole (10) and the surface of the cover plate (2) is 75°.
6. The noise-reducing composite aluminum plate according to claim 1, characterized in that: The snap-fit assembly includes a snap-fit groove (103) at both ends of the substrate (1) and elastic snap-fit blocks (201) on both sides of the cover plate (2). The bottom of the snap-fit groove (103) is provided with a silicone rubber sealing gasket (11) with a compression rate of 20%-30%. The elastic snap-fit blocks (201) and the snap-fit groove (103) form an interference fit.
7. The noise-reducing composite aluminum plate according to claim 1, characterized in that: The trapezoidal wave structure of the supporting frame (4) has an inclination angle of 55°-65°.
8. The noise-reducing composite aluminum plate according to claim 1, characterized in that: The pore size gradient distribution of the tapered through hole (10) satisfies the following: the pore density in the central region of the cover plate (2) is 60-80 pores / dm², and the pore density in the edge region is 30-50 pores / dm².