A low frequency broadband submerged acoustic metamaterial structure

Abstract

The application discloses a low-frequency broadband sunken acoustic metamaterial structure, which comprises a tungsten mass block layer, a silicone rubber layer and an epoxy resin substrate layer, characterized in that the hexagonal substrate is a honeycomb hexagon, the upper and middle portions of the hexagonal substrate are provided with silicone rubber, the lower column of the silicone rubber is bonded with the hexagonal substrate, the mass block is embedded in the silicone rubber, the radius of the silicone rubber is larger than that of the mass block, the lower surface of the mass block can sink to the interior of the silicone rubber by a depth of 3.75-9 mm, and the mass block is tungsten with a radius of 4-5.5 mm and a thickness of 3.75-6.75 mm. In the use, the calculation and analysis based on COMSOL are carried out, the structure of the composite columnar vibrator is changed, the different optimization requirements of the metamaterial can be met by changing some parameters under the condition of meeting the sound insulation characteristics, the band gap interval is optimized in a specific frequency range, the noise of a specific frequency is targeted, and the overall noise reduction performance of the metamaterial is improved.

Description

Technical Field

[0001] This invention relates to the field of vibration and noise control technology, specifically to a low-frequency broadband sunken acoustic metamaterial structure. Background Technology

[0002] With social development and progress, modern transportation (automobiles, trains, airplanes, ships, manned spacecraft, engineering vehicles, etc.), smart home appliances and high-tech electronics (air conditioners, refrigerators, noise-canceling headphones, etc.), energy, construction and residential engineering fields have increasingly urgent demands for acoustic quality, thus requiring control of noise across the entire frequency band (low, mid, and high frequencies). Mid- and high-frequency noise corresponds to short wavelengths and weak propagation capabilities, which can be effectively controlled using traditional sound-absorbing materials. However, because low-frequency noise (below 1000Hz, especially below 500Hz) corresponds to long wavelengths and strong propagation capabilities, traditional sound-absorbing materials can only control low-frequency noise by significantly increasing the material thickness / weight. How to effectively suppress low-frequency noise and achieve efficient broadband sound absorption is a major challenge facing the academic and engineering communities.

[0003] Acoustic metamaterials are one of the most cutting-edge disciplines in acoustics research. They achieve effective control of sound waves through the design of appropriate structural configurations, possessing extraordinary acoustic properties, especially for low-frequency (1-1000Hz) noise problems that are difficult to solve with conventional sound insulation materials. Research on acoustic metamaterials originated from locally resonant phononic crystals, a concept first proposed in 2000. A simple locally resonant phononic crystal model can be constructed by artificially arranging locally resonant units periodically in an elastic medium. Research has shown that it can form low-frequency band gaps within certain specific ranges. The concept of acoustic metamaterials was first proposed in 2004. In the past decade, with the emergence and development of acoustic metamaterials, significant progress has been made in low-frequency noise control. However, traditional acoustic metamaterials based on the principle of local resonance directly generate very narrow acoustic bandwidths and lack broadband noise reduction effects, thus limiting their practicality to some extent.

[0004] The acoustic properties of acoustic metamaterials are analyzed based on their structural band gaps. Low-frequency band gaps can suppress low-frequency noise, but the lower the band gap, the greater the optimization difficulty and the higher the requirements for the structure and materials. Therefore, how to design acoustic metamaterial structures and optimize them while ensuring a reasonable metamaterial configuration to improve their acoustic performance is an important research topic. Summary of the Invention

[0005] The purpose of this invention is to provide a low-frequency broadband sunken acoustic metamaterial structure to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a low-frequency broadband sunken acoustic metamaterial structure, comprising a tungsten mass block layer, a silicone rubber layer, and an epoxy resin substrate layer, characterized in that: the hexagonal substrate is a honeycomb hexagon, a silicone rubber is disposed in the upper middle part of the hexagonal substrate, and the lower column of the silicone rubber is bonded to the hexagonal substrate, a mass block is embedded inside the silicone rubber, and the radius of the silicone rubber is larger than the radius of the mass block, and the lower surface of the mass block can sink to a depth of 3.75-9mm into the interior of the silicone rubber.

[0007] Preferably, the mass block is tungsten with a radius of 4-5.5 mm and a thickness of 3.75-6.75 mm, and the specific parameters of the mass block are a density ρ = 19100 kg / m³. 3 The elastic modulus is E = 3.54 × 10⁻⁶. 11 Pa, Poisson's ratio is 0.35.

[0008] Preferably, the silicone rubber is a silicone rubber with a radius of 6 mm and a thickness of 9 mm, and the specific parameters of the silicone rubber are a density ρ = 1300 kg / m³. 3 The shear modulus is G = 4.68 × 10⁻⁶. 4 Pa, elastic modulus E = 1.2 × 10⁻⁶ 5 Pa, Poisson's ratio is 0.47.

[0009] Preferably, the lattice constant of the hexagonal substrate is 30 mm, and the side length of the hexagonal substrate is... The epoxy resin substrate, with a thickness of 1 mm and a diameter of mm, has a density ρ = 1180 kg / m³. 3 The elastic modulus is E = 4.35 × 10⁻⁶. 9 Pa, Poisson's ratio is 0.37.

[0010] Compared with the prior art, the beneficial effects of the present invention are:

[0011] This invention relates to a low-frequency broadband submerged acoustic metamaterial structure. By submerging a mass block into silicone rubber, simulation data is obtained based on COMSOL calculations and analysis. By comparing the traditional structure and the submerged structure under the same parameter conditions, the sound insulation frequency of the submerged structure is 495Hz, which is wider than the 180Hz sound insulation frequency range of the traditional structure. The deeper the submersion, the higher the frequencies corresponding to the sound insulation peaks and valleys are shifted. In this way, the low-frequency broadband sound-absorbing metamaterial of this invention achieves the function of sound wave attenuation. Attached Figure Description

[0012] Figure 1 This is a three-dimensional view of the sunken structure of the acoustic metamaterial with low-frequency broadband noise reduction function of the present invention;

[0013] Figure 2 This is a cross-sectional view of the sunken structure of the acoustic metamaterial with low-frequency broadband noise reduction function of the present invention;

[0014] Figure 3 This is a top view of the sunken structure of the acoustic metamaterial with low-frequency broadband noise reduction function of the present invention;

[0015] Figure 4 The image shows the acoustic test results of the acoustic metamaterial with low-frequency broadband noise reduction function of the present invention.

[0016] In the diagram: 1. Hexagonal substrate; 2. Mass block; 3. Silicone rubber. Detailed Implementation

[0017] 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 only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1-4 The present invention provides a technical solution: a low-frequency broadband sunken acoustic metamaterial structure, comprising a tungsten mass block layer, a silicone rubber layer, and an epoxy resin substrate layer. The hexagonal substrate 1 is a honeycomb hexagon. A silicone rubber 3 is disposed in the upper middle part of the hexagonal substrate 1, and the lower column of the silicone rubber 3 is bonded to the hexagonal substrate 1. A mass block 2 is embedded inside the silicone rubber 3, and the radius of the silicone rubber 3 is larger than the radius of the mass block 2. The lower surface of the mass block 2 can sink to a depth of 3.75-9mm into the interior of the silicone rubber 3.

[0019] Mass block 2 is tungsten with a radius of 4-5.5 mm and a thickness of 3.75-6.75 mm. The specific parameters of mass block 2 are: density ρ = 19100 kg / m³. 3 The elastic modulus is E = 3.54 × 10⁻⁶. 11 Pa, Poisson's ratio is 0.35;

[0020] Silicone rubber 3 is a type of silicone rubber with a radius of 6 mm and a thickness of 9 mm. Specific parameters of silicone rubber 3 include a density ρ = 1300 kg / m³. 3 The shear modulus is G = 4.68 × 10⁻⁶. 4 Pa, elastic modulus E = 1.2 × 10⁻⁶ 5 Pa, Poisson's ratio is 0.47;

[0021] The lattice constant of hexagonal substrate 1 is 30 mm, and the side length of hexagonal substrate 1 is... The epoxy resin substrate 1, with a thickness of 1 mm and a diameter of mm, has a density ρ = 1180 kg / m³. 3 The elastic modulus is E = 4.35 × 10⁻⁶. 9 Pa, Poisson's ratio is 0.37.

[0022] Working principle: When in use, the presence of local resonant units alters the dispersion relationship within the board, triggering resonance in the local resonant units at the lower boundary of the band gap. Energy is concentrated in the resonant units, resulting in a noticeable sound insulation peak. At the upper boundary of the band gap, energy is mainly concentrated in the hexagonal substrate 1, creating a sound insulation valley. The resonant units at the sound insulation peak concentrate a large amount of energy, while the energy at the sound insulation valley is mainly concentrated in the hexagonal substrate 1, significantly widening the sound insulation band gap. This effectively suppresses low-frequency noise and achieves efficient broadband sound absorption.

[0023] When used, this invention, based on COMSOL-based calculations and analysis, modifies the structure of the composite columnar oscillator to meet the sound insulation requirements while satisfying different optimization needs of the metamaterial by changing certain parameters: optimizing the bandgap range within a specific frequency range to target noise at specific frequencies; and improving the overall noise reduction performance of the metamaterial.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-frequency broadband sunken acoustic metamaterial structure, comprising a tungsten mass layer, a silicone rubber layer, and a hexagonal substrate, characterized in that: The hexagonal substrate (1) is a honeycomb hexagon. Silicone rubber (3) is provided in the upper middle part of the hexagonal substrate (1), and the lower column of the silicone rubber (3) is bonded to the hexagonal substrate (1). A mass block (2) is embedded inside the silicone rubber (3), and the radius of the silicone rubber (3) is greater than the radius of the mass block (2). The lower surface of the mass block (2) can sink to a depth of 3.75-9mm into the silicone rubber (3). The mass block (2) is tungsten with a radius of 4-5.5 mm and a thickness of 3.75-6.75 mm. The specific parameters of the mass block (2) are: density ρ = 19100 kg / m³. 3 The elastic modulus is E = 3.54 × 10⁻⁶. 11 Pa, Poisson's ratio is 0.35; The silicone rubber (3) is a silicone rubber with a radius of 6 mm and a thickness of 9 mm. The specific parameters of the silicone rubber (3) are a density ρ = 1300 kg / m³. 3 The shear modulus is G = 4.68 × 10⁻⁶. 4 Pa, elastic modulus E = 1.2 × 10⁻⁶ 5 Pa, Poisson's ratio is 0.47; The lattice constant of the hexagonal substrate (1) is 30 mm, and the side length of the hexagonal substrate (1) is... Epoxy resin with a thickness of 1 mm and a diameter of 1 mm, hexagonal substrate (1) with specific parameters of density ρ = 1180 kg / m³ 3 The elastic modulus is E = 4.35 × 10⁻⁶. 9 Pa, Poisson's ratio is 0.37.

Images