3D printing resonator array layer low-noise pavement structure

Abstract

The invention relates to a 3D printed resonator array layer low-noise pavement structure, and belongs to the field of road traffic engineering.The pavement structure comprises a surface layer, a base layer and a cushion layer, and the surface layer is provided with an upper surface layer, a middle surface layer and a lower surface layer from top to bottom; wherein the upper surface layer adopts a porous surface layer, the middle surface layer adopts a 3D printing resonator array layer, and the lower surface layer adopts a porous surface layer or a 3D printing resonator array layer; the structure of the 3D printing resonator array layer comprises a periodic structure, a scatterer array structure based on Wills coupling and a cavity labyrinth unit structure; the structure of the surface layer adopts one of the following forms: a multi-layer resonator array combination form, a resonator array sandwich form and a resonator array gradient hierarchy form. The pavement structure disclosed by the invention can realize the effects of wide-frequency-domain sound absorption and low-frequency-band energy reduction, and has good structural strength and weather resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of road traffic engineering, and particularly relates to a 3D printing resonator array layer low-noise pavement structure. BACKGROUND

[0002] With the rapid development of urbanization and the continuous growth of transportation demand, road traffic noise has become one of the main environmental pollution sources in modern cities, seriously affecting the quality of life and health of residents. A large number of studies have shown that the noise generated by the contact between the tire and the road occupies a dominant position in the overall traffic noise, and its frequency range covers 10Hz to 2000Hz, among which the low-frequency noise has a long propagation distance and slow attenuation, and is more difficult to control by traditional means. Although the existing control measures such as sound barriers can reduce the noise level on both sides of the road to a certain extent, they are high in cost and large in occupation, and have adverse effects on urban landscape and driving safety, so they are not suitable for large-scale promotion in urban roads. In contrast, reducing tire / road noise from the source of the road is considered to be the most economical and effective way to reduce noise.

[0003] The existing low-noise pavement has the following problems:

[0004] (1) The existing low-noise pavement mainly relies on porous asphalt pavement, which realizes sound energy absorption by increasing the void ratio, and can usually reduce noise by 2-8dB, but its noise reduction effect is mainly concentrated in the medium and high frequency bands, and the reduction of low-frequency noise is very limited. The traditional porous asphalt pavement is almost ineffective in reducing noise in the low frequency band of 200Hz-500Hz. At the same time, the internal pore morphology of the porous pavement is greatly affected by the material gradation and construction process, resulting in that the actual noise reduction performance is often difficult to match the theoretical model. In recent years, some researchers have also proposed a porous elastic pavement, which uses polyurethane and other high molecular materials as a binder, and through the synergistic effect of multiple mechanisms such as sound absorption, vibration reduction and reduction of mechanical impedance, the noise reduction effect is improved to 8-10dB. However, this kind of pavement material has insufficient strength and poor durability, and is difficult to withstand long-term traffic load and complex climate environment, so its engineering application range is greatly limited, and it is difficult to meet the demand of more than 10dB of urban traffic noise exceeding the standard.

[0005] (2) The existing technology introduces Helmholtz resonator and other acoustic metamaterials into the road structure. The invention patent with application publication number US5730548A discloses a pavement noise reduction treatment and its implementation method, which realizes pavement noise reduction by arranging Helmholtz resonators in the surface layer. The low-frequency noise of a specific frequency is reduced through the resonance effect, but due to the difficulty in accurately arranging the resonator in the pavement structure and the easy filling and blocking of the resonator by asphalt or concrete materials, the noise reduction effect in actual engineering is not ideal, and there are problems of insufficient arrangement precision and material weather resistance. The existing technology of directly burying the resonator in asphalt often fails due to uneven construction.

[0006] Therefore, current low-noise pavement technologies generally suffer from problems such as narrow noise reduction bandwidth, insufficient low-frequency attenuation, limited noise reduction levels, and poor long-term service performance, making it difficult to meet the increasingly prominent noise pollution control needs of urban roads. Especially in high-volume, complex traffic environments, roadside noise levels often exceed 10 dB, and existing measures such as porous asphalt pavements and sound barriers are insufficient for effective control. How to simultaneously achieve wide-band noise absorption and effective low-frequency energy reduction while ensuring road performance and durability has become a key challenge that urgently needs to be addressed in current low-noise pavement technologies. Summary of the Invention

[0007] The purpose of this invention is to at least address one of the aforementioned technical deficiencies.

[0008] Therefore, the purpose of this invention is to propose a low-noise road surface structure with a 3D-printed resonator array layer, which can achieve the effects of wide-frequency sound absorption and low-frequency energy reduction, and has good structural strength and weather resistance.

[0009] To achieve the above objectives, embodiments of the present invention provide a low-noise road surface structure with a 3D-printed resonator array layer. The road surface structure includes a surface layer, a base layer, and a subbase layer from top to bottom. The surface layer is provided with an upper surface layer, a middle surface layer, and a lower surface layer from top to bottom. The upper surface layer is a porous surface layer, the middle surface layer is a 3D-printed resonator array layer, and the lower surface layer is either a porous surface layer or a 3D-printed resonator array layer.

[0010] The structure of the 3D printed resonator array layer includes: a periodic structure, a scatterer array structure based on Wills coupling, and a cavity labyrinth unit structure.

[0011] The periodic structure includes: an elastic ultrathin surface layer made of porous medium arranged from top to bottom and a plurality of adjacent resonator cavities, wherein the elastic ultrathin surface layer made of porous medium and the resonator cavities together form a composite surface structure; each resonator cavity has an opening at the top to communicate with the elastic ultrathin surface layer made of porous medium.

[0012] The scatterer array structure based on Wills coupling includes: a porous medium and multiple scattering functional units embedded in the porous medium; wherein, the multiple scattering functional units are arranged in an array within the porous medium, and the interior and exterior surfaces of each scattering functional unit form a connected scattering structure to form a resonator cavity and communicate with the porous medium.

[0013] The cavity labyrinth unit structure includes: an elastic ultrathin surface layer composed of porous medium arranged from top to bottom and an acoustic metastructure array composed of multiple U-shaped functional units; the multiple U-shaped functional units are interconnected and form multiple interconnected cavities in a labyrinth shape to form a resonator cavity; each U-shaped functional unit has an opening at the top to communicate with the elastic ultrathin surface layer composed of porous medium;

[0014] The surface layer has one of the following structures:

[0015] (1) Multilayer resonator array combination form: the upper layer adopts a porous surface layer, the middle layer and the lower layer adopt a 3D printed resonator array layer that is connected vertically; wherein, the middle layer is stacked with one or more 3D printed resonator array layers to form a vertical multilayer resonator system;

[0016] (2) Sandwich form of resonator array: the upper layer is a porous surface layer, the middle layer is a 3D printed resonator array layer, and the lower layer is a porous surface layer; wherein, the top and bottom of each resonator cavity in the middle layer are provided with openings;

[0017] (3) Resonator array gradient layer form: the upper layer adopts a porous surface layer, the middle layer adopts a 3D printed resonator array layer based on Wills coupling scatterer array structure, and the lower layer adopts a 3D printed resonator array layer with periodic structure or cavity labyrinth unit structure.

[0018] Furthermore, the resonator cavity of the periodic structure can be one of the following shapes: cylindrical cavity, rectangular cavity, and spherical cavity.

[0019] Furthermore, each of the scattering functional units adopts a cylindrical structure, with multiple interconnected cavities formed inside and on the surface of the cylindrical structure, scattering outward from the center.

[0020] Furthermore, the bottom or side of the resonator cavity of the periodic structure is further provided with an opening to connect with the porous surface layer or resonator array below or to the side;

[0021] The bottom or side of the zigzag functional element of the cavity labyrinth unit structure is further provided with an opening to connect with the porous surface layer or resonator array below or to the side.

[0022] Furthermore, the resonant frequency f of the multilayer resonator array combination is... 0,k for:

[0023]

[0024] Each layer of the resonator array is denoted as the k-th layer, where k = 1, 2, ..., N, and N is the layer number; A k V is the cross-sectional area of ​​the neck; k L represents the volume of the cavity. eff,k λ is the effective length of the neck; c is the speed of sound.

[0025] Furthermore, in the sandwich configuration of the resonator array, the resonant frequency f is achieved when openings are provided at the top and bottom of each individual resonator cavity. 0,i for:

[0026]

[0027] Where i represents the i-th resonant cavity in the resonator array layer; A i V is the cross-sectional area of ​​the neck; i L represents the volume of the cavity. eff,i λ is the effective length of the neck; c is the speed of sound.

[0028] Furthermore, in the sandwich configuration of the resonator array, the resonant frequency is achieved when openings are provided on the top, bottom, and sides of each individual resonator cavity. for:

[0029]

[0030] Where i represents the i-th resonant cavity in the resonator array layer; V i c is the volume of the cavity; c is the speed of sound;

[0031] The effective neck cross-sectional area represents the total area of ​​the open region that can participate in acoustic wave coupling.

[0032] A 顶 A represents the area of ​​the opening on the upper surface of the neck, i.e., the area of ​​the hole connecting the top of the resonator to the outside world; 底 A represents the area of ​​the opening at the bottom of the neck, i.e., the area of ​​the opening at the bottom of the resonator that connects downwards or allows for ventilation; 侧 This refers to the area of ​​the lateral opening in the neck, which appears in resonators with side-hole structures or perforated housings;

[0033] The effective length of the neck.

[0034] L i ΔL is the basic effective length of the resonator cavity, i.e., the straight-line length without considering structural disturbances; 顶 The additional sound path length caused by the top connection; ΔL 底 The additional sound path length caused by disturbances in the bottom structure or openings; ΔL 侧This refers to the additional sound path length caused by the opening in the side wall.

[0035] Furthermore, the resonant frequency f in the gradient hierarchy of the resonator array 0,k for:

[0036]

[0037] Each layer of the resonator array is denoted as the k-th layer; A k V is the cross-sectional area of ​​the neck; k For cavity volume, L eff,k λ is the effective length of the neck; c is the speed of sound.

[0038] Furthermore, the 3D-printed resonator array layer can be fixed to the base layer in the following way:

[0039] (1) Integral prefabricated plate: The 3D printed resonator array layer is manufactured by integral printing, and the width of the plate is the same as the width of the lane; the bottom is provided with a rough surface or prefabricated groove to form a mechanical interlock with the cement base;

[0040] (2) Embedded Units: The 3D printed resonator array layer is divided into multiple embedded units, which are combined and embedded according to the pre-reserved slots of the designed array spacing and depth. After embedding, the units are backfilled and sealed with cement mortar or polymer mortar to prevent the units from loosening or shifting. The gaps between the embedded units are filled with elastic material.

[0041] Furthermore, the resonator array arrangement of the 3D printed resonator array layer includes:

[0042] Regular rectangular array: Each resonator array is arranged in a straight line with equal spacing, corresponding to the acoustic frequency band coverage of 200-600Hz;

[0043] Honeycomb layout: Each resonator array adopts a hexagonal close-packed arrangement, corresponding to the acoustic frequency band coverage of 300-800Hz;

[0044] Interleaved arrangement: Adjacent resonator arrays are arranged in a staggered manner, corresponding to the acoustic frequency band coverage of 400-1000Hz.

[0045] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0046] The 3D-printed resonator array layer low-noise pavement structure of the present invention achieves a composite low-noise pavement that can balance wide-frequency sound absorption and low-frequency energy reduction, and has good structural strength and weather resistance.

[0047] (1) Significantly broaden the noise reduction frequency band: This invention lays out a 3D printed resonator array layer in the road surface structure, so that the road surface forms resonance absorption in the low frequency band and couples with the high frequency sound absorption mechanism of the porous surface layer, thus achieving a wide frequency range of noise reduction from 10Hz to 2000Hz, solving the problem of insufficient low frequency control of existing low noise road surfaces.

[0048] (2) Improve the noise reduction amplitude: Through the synergistic effect of the porous surface layer and the resonator array, the noise reduction level of this invention is increased by more than 50% compared with traditional road surfaces, and the overall noise reduction amplitude can reach 8-12dB, which has a stronger application effect in complex urban environments.

[0049] (3) Ensure structural accuracy and controllability: The present invention uses 3D printing to prefabricate the resonator array, which can achieve high-precision control of cavity geometry and parameters, ensuring that the resonant frequency matches the target noise frequency band, thereby improving the stability and consistency of the noise reduction effect.

[0050] (4) Enhancing Material Durability: Ordinary 3D printed concrete lacks coarse aggregate, resulting in insufficient strength and weather resistance, making it difficult to meet the requirements for long-term road service. This invention enhances organic-inorganic compatibility by adding polymers and silane coupling agents to concrete, significantly improving the material's compressive strength, crack resistance, freeze-thaw resistance, and corrosion resistance, ensuring that the resonator array maintains structural integrity and functional stability under long-term traffic loads and complex environments.

[0051] (5) Optimized installation and construction convenience: The resonator array of the present invention can be arranged in an integral prefabricated panel or unit embedding method, with adjustable arrangement depth and spacing, and guaranteed connectivity between the opening and the surface layer, avoiding blockage or deviation problems during construction. At the same time, the arrangement method of the present invention is compatible with conventional porous asphalt or polyurethane mixture paving process, and will not significantly increase the construction difficulty and cycle.

[0052] (6) Indoor verifiable performance optimization: Through indoor methods such as impedance tube sound absorption test and reverberation chamber transmission loss test, the present invention can repeatedly verify the mechanical and acoustic performance under different parameter combinations under laboratory conditions, quickly screen the best design scheme, avoid the large amount of cost and time required by traditional full-scale test section verification, and improve R&D efficiency and scheme reliability.

[0053] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0054] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0055] Figure 1 This is a schematic diagram of a 3D-printed resonator array layer with a periodic structure according to an embodiment of the present invention;

[0056] Figure 2 A cross-sectional schematic diagram of a periodic resonator array with cylindrical and rectangular cavities according to an embodiment of the present invention;

[0057] Figure 3 This is a cross-sectional schematic diagram of a periodic resonator array in a spherical cavity according to an embodiment of the present invention;

[0058] Figure 4 This is a schematic diagram of a 3D-printed resonator array layer based on a Wills-coupled scatterer array structure according to an embodiment of the present invention.

[0059] Figure 5 This is a schematic diagram of a scattering functional unit according to an embodiment of the present invention;

[0060] Figure 6 This is a schematic diagram of a 3D-printed resonator array layer of a cavity labyrinth unit structure according to an embodiment of the present invention;

[0061] Figure 7 These are schematic diagrams of different numbers of cavity labyrinth unit structures according to embodiments of the present invention;

[0062] Figure 8 This is a schematic diagram of a road surface structure in the form of a multilayer resonator array according to an embodiment of the present invention;

[0063] Figure 9 This is a schematic diagram of a road surface structure in the form of a resonator array sandwich, according to an embodiment of the present invention.

[0064] Figure 10 This is a schematic diagram of a road surface structure in the form of a resonator array gradient hierarchy according to an embodiment of the present invention;

[0065] Figure 11 This is a schematic diagram of a resonator array arranged in a regular rectangular array according to an embodiment of the present invention;

[0066] Figure 12 This is a schematic diagram of a resonator array arranged in a honeycomb pattern according to an embodiment of the present invention;

[0067] Figure 13 This is a schematic diagram of an interleaved resonator array according to an embodiment of the present invention.

[0068] Explanation of annotations in the image:

[0069] 1-An elastic, extremely thin surface layer composed of porous medium; 2-Resonator cavity; 3-Porous medium; 4-Scattering functional element; 5-U-shaped functional element. Detailed Implementation

[0070] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0071] The 3D-printed resonator array layer low-noise road surface structure of this invention comprises, from top to bottom, a surface layer, a base layer, and a subbase layer. The surface layer consists of a top layer, a middle layer, and a bottom layer, arranged from top to bottom.

[0072] In this invention, the upper layer is a porous surface layer, the middle layer is a 3D printed resonator array layer, and the lower layer is a porous surface layer or a 3D printed resonator array layer.

[0073] The porous surface layer can be either porous asphalt pavement or polyurethane porous elastic pavement, used to achieve sound energy absorption in the mid-to-high frequency range. The 3D-printed resonator array layer is fabricated using a 3D printing process to achieve sound energy absorption in the low frequency range. The 3D printing process of the 3D-printed resonator array layer adopts a layer-by-layer stacking method, and the printing path uses a combination of "interlaced + parallel" to reduce anisotropy caused by poor interlayer bonding.

[0074] In this invention, the structure of the 3D printed resonator array layer can take various forms, including: periodic structure, scatterer array structure based on Wills coupling, and cavity labyrinth unit structure.

[0075] (1) Periodic structure

[0076] like Figure 1 As shown, the periodic structure includes: an elastic ultrathin surface layer 1 made of porous medium arranged from top to bottom, and multiple adjacent resonator cavities 2. The elastic ultrathin surface layer 1 made of porous medium and the resonator cavities 2 together form a composite surface structure. Each resonator cavity 2 has an opening at the top to communicate with the elastic ultrathin surface layer 1 made of porous medium.

[0077] To avoid direct contact between the opening end of the resonator cavity 2 and the tire, this invention uses a porous medium with a thickness of 5-10 mm to form an elastic ultrathin surface layer 1, which is combined with the resonator cavity 2 to form a composite surface structure. The material of the porous medium elastic ultrathin surface layer 1 is high-viscosity modified asphalt.

[0078] like Figure 2 and Figure 3 As shown, the resonator cavity 2 of the periodic structure can take one of the following shapes: a cylindrical cavity with openings, a rectangular cavity, or a spherical cavity.

[0079] It should be noted that the shape of the resonator cavity 2 is not limited to the examples above, and can also be other shapes, such as irregular shapes, as long as the shape of the resonator cavity 2 is such that at least the top has an opening.

[0080] In addition, the resonator cavity 2 with a periodic structure can also have openings at its bottom or side, in addition to the top opening, so as to connect with the porous surface layer or resonator array below or to the side.

[0081] The periodic structure is mainly used for resonant energy dissipation in the low-frequency band of the tire / road noise spectrum. Through the synergistic effect of the upper and lower layers, a superposition effect of resistive and reactive noise reduction is achieved, thereby realizing efficient noise reduction in a wide frequency range of 10Hz to 2000Hz.

[0082] Furthermore, besides periodic structures, the internal structure of materials can be precisely designed at fine and microscale levels to locally alter the propagation speed and direction of sound waves, achieving effects such as negative refraction of sound waves and directional propagation of sound beams. Based on this, this invention further proposes a scatterer array structure and a cavity labyrinth unit structure.

[0083] (2) Scatterer array structure based on Wills coupling (cross-coupling between strain and velocity)

[0084] like Figure 4 As shown, the scatterer array structure based on Wills coupling includes a porous medium 3 and multiple scattering functional elements 4 embedded in the porous medium. The multiple scattering functional elements 4 are arranged in an array within the porous medium 3, and the interior and outer surface of each scattering functional element 4 form a connected scattering structure to form a resonator cavity, which is connected to the porous medium 3.

[0085] like Figure 5 As shown, each scattering functional unit 4 adopts a cylindrical structure, forming multiple interconnected cavities inside and on the surface of the cylindrical structure, scattering outwards from the center. By slotting the surface of the cylindrical structure, not only are cavities connected to the interior formed, but also connections are achieved with the surrounding porous medium, thus realizing an overall interconnected structure from top to bottom.

[0086] The scatterer array based on Wills coupling proposed in this invention adopts an embedded approach and enables the directional propagation of sound waves and reduces energy through a suitable scattering structure. Its fabrication method is relatively simple.

[0087] (3) Hollow labyrinth unit structure

[0088] like Figure 6As shown, the cavity labyrinth unit structure includes: an elastic ultrathin surface layer 1 composed of porous medium arranged from top to bottom, and an acoustic metastructure array composed of multiple U-shaped functional units 5. The multiple U-shaped functional units 5 are interconnected, forming multiple interconnected cavities in a labyrinthine pattern to form a resonator cavity. Each U-shaped functional unit 5 has an opening at its top to communicate with the elastic ultrathin surface layer 1 composed of porous medium.

[0089] The cavity labyrinth unit structure adjusts the noise spectrum by designing a frequency band that conforms to the Fabry-Pérot (FP) resonance. Considering the applicability to road structures, a porous material medium (porous elastic composite) is integrated with an acoustic metamaterial array to form an acoustic metamaterial structure that integrates porous sound absorption and spectrum control functions. The size and shape of the internal cavity of the U-shaped functional unit 5 are key factors determining the bandgap.

[0090] Figure 6 The combination of three zigzag functional units is shown. Each zigzag functional unit 5 has three cavities, and its top opening is connected to an elastic ultrathin surface layer 1 composed of porous medium.

[0091] Figure 7 The diagram shows cavity labyrinth unit structures with different numbers (n = 2, 4, 6, 8, 10). Here, n represents the number of cavities within the zigzag functional unit 5. A larger value for n results in better noise reduction.

[0092] Since this invention involves a moving load, the length of a single U-shaped functional element 5 is generally set to 5–10 cm; within this length, n is typically 3–5. For example, Figure 6 Each of the 5-shaped functional units in the middle has 3 cavities, i.e., n=3.

[0093] It should be noted that, in addition to the top opening, the hollow labyrinth unit structure's shaped functional element may also have openings on its bottom or side to connect with the porous surface layer or resonator array below or on the side.

[0094] The surface layer of the road structure of the present invention has one of the following structural forms:

[0095] 1. Multilayer resonator array configuration: The upper layer uses a porous surface layer, and the middle and lower layers use interconnected 3D-printed resonator array layers. The middle layer contains one or more stacked 3D-printed resonator array layers, forming a vertically multilayer resonant system.

[0096] like Figure 8As shown, a multi-layer resonator array with intermediate and lower layers is sequentially arranged beneath the porous surface layer. Multiple resonant cavities can also be stacked within the intermediate layer, forming a vertically multi-layer resonant system. Resonant cavities of different depths correspond to different resonant frequencies, creating multiple absorption peaks within the 200–800 Hz range, enabling segmented control of the low- to mid-frequency range. The stacking of multiple cavities significantly broadens the effective absorption bandwidth, particularly in the 200–600 Hz low-frequency range where traditional porous pavements struggle, thus improving the overall broadband noise reduction performance under tire-road contact excitation.

[0097] The multilayer resonator array combination structure is suitable for noise reduction in the entire frequency band of 200-800Hz, and has a significant absorption effect on the low frequency energy peak of 250-500Hz. Compared with ordinary porous pavement, it can increase low frequency noise reduction by 1-3dB(A), and can reduce overall noise by 4-8dB(A) compared with dense asphalt pavement.

[0098] In this invention, the multilayer resonator array combination has the following structural forms:

[0099] (1) Top layer: porous surface layer; middle layer: periodic structure; bottom layer: periodic structure.

[0100] (2) Top layer: porous surface layer; middle layer: scatterer array structure based on Wills coupling; bottom layer: scatterer array structure based on Wills coupling.

[0101] (3) Top layer: porous surface layer; middle layer: cavity labyrinth unit structure; bottom layer: cavity labyrinth unit structure.

[0102] This invention allows the resonant frequency to be tuned to the target noise frequency band by adjusting the cavity volume, neck diameter (correspondingly adjusting the neck cross-sectional area), and neck length. Multiple resonant units are arranged in an array to achieve wideband noise reduction through frequency coverage.

[0103] In this invention, the resonant frequency f of the multilayer resonator array combination is... 0,k for:

[0104]

[0105] Each layer or type of resonator array is denoted as the k-th layer, where k = 1, 2, ..., N; N is the layer number; A k The cross-sectional area of ​​the neck is in mm. 2 V k The volume of the cavity is in mm. 3 L eff,k λ represents the effective length of the neck, in mm; c represents the speed of sound, in m / s; π represents pi.

[0106] To form multiple absorption peaks within the 200–800 Hz range, a set of target frequencies can be selected. (For example, using a 1 / 3 octave band layout), the geometric dimensions are then determined using the inverse calculation formula:

[0107]

[0108] On the same plane, these resonator arrays operate in parallel to the incident sound wave, and their equivalent surface compliance (equivalent "spring") can be denoted as:

[0109]

[0110] The corresponding equivalent surface impedance is approximately:

[0111]

[0112] Where ω is the angular frequency, ω = 2πf, with units of rad / s; ρ is the air density, with units of kg / m³. 3 At standard atmospheric pressure, it is approximately 1.21 kg / m³. 3 .

[0113] Therefore, in multiple f 0,k A resonant absorption peak appears at this point, enabling segmented control and bandwidth expansion of the 200–800 Hz frequency range (especially 250–500 Hz).

[0114] 2. Sandwich configuration of the resonator array: The upper layer is a porous surface layer, the middle layer is a 3D-printed resonator array layer, and the lower layer is a porous surface layer. The top and bottom of each individual resonator cavity in the middle layer are provided with openings.

[0115] like Figure 9 As shown, the sandwich structure adopts a combination of porous surface layer + resonator array layer + porous surface layer. In addition to the openings at the top and bottom, the single resonator can have openings on the side or use 3D printing materials with microporous characteristics, so that the resonator cavity and the porous surface layer form a multi-directional interconnected network.

[0116] The sandwich-shaped upper and lower porous layers can provide continuous absorption in the mid-to-high frequencies of 800–1000 Hz, while the middle resonant layer forms a sharp resonant peak in the 400–800 Hz range. Lateral openings can enhance the coupling between the cavity and the airflow and pore network, allowing sound energy to form more complex dissipation paths inside and outside the cavity, which is particularly effective for mid-frequency spikes caused by tire tread impacts.

[0117] The sandwich structure is mainly effective in the 400-900Hz frequency band and can form 1-2 obvious resonance peaks in the 400-800Hz frequency band. Compared with ordinary porous pavement, it can improve the insertion loss by 1-2dB(A) in the mid-frequency band and achieve a comprehensive noise reduction effect of 5-8dB(A) compared with dense asphalt pavement.

[0118] The sandwich configuration of resonator arrays has the following structural forms:

[0119] (1) Top layer: porous surface layer; middle layer: periodic structure; bottom layer: porous surface layer.

[0120] (2) Top layer: porous surface layer; middle layer: scatterer array structure based on Wills coupling; bottom layer: porous surface layer.

[0121] (3) Top layer: porous surface layer; middle layer: hollow labyrinth unit structure; bottom layer: porous surface layer.

[0122] This invention allows the resonant frequency to be tuned to the target noise frequency band by adjusting the cavity volume, neck diameter (correspondingly adjusting the neck cross-sectional area), and neck length. Multiple resonant units are arranged in an array to achieve wideband noise reduction through frequency coverage.

[0123] 2.1 In a sandwich configuration of a resonator array, the resonant frequency f is achieved when openings are located at both the top and bottom of a single resonator cavity. 0,i for:

[0124]

[0125] Where i represents the i-th resonant cavity in the resonator array layer; A i V is the cross-sectional area of ​​the neck; i L represents the volume of the cavity. eff,i λ is the effective length of the neck; c is the speed of sound.

[0126] 2.2 In the sandwich configuration of the resonator array, the effective area and effective length are altered by lateral openings or micro-perforated materials in the resonator cavity. Therefore, this invention proposes a resonant frequency when openings are provided on the top, bottom, and sides of a single resonator cavity. for:

[0127]

[0128] Where i represents the i-th resonant cavity in the resonator array layer; V i c is the volume of the cavity; c is the speed of sound;

[0129] The effective neck cross-sectional area represents the total area of ​​the open region that can participate in acoustic wave coupling.

[0130] A 顶 A represents the area of ​​the opening on the upper surface of the neck, i.e., the area of ​​the hole connecting the top of the resonator to the outside world; 底A represents the area of ​​the opening at the bottom of the neck, i.e., the area of ​​the opening at the bottom of the resonator that connects downwards or allows for ventilation; 侧 This refers to the area of ​​the lateral opening in the neck, which appears in resonators with side-hole structures or perforated housings;

[0131] The effective length of the neck.

[0132] L i ΔL is the basic effective length of the resonator cavity, i.e., the straight-line length without considering structural disturbances; 顶 The additional sound path length caused by the top connection; ΔL 底 The additional sound path length caused by disturbances in the bottom structure or openings; ΔL 侧 The additional sound path length caused by openings in the sidewall (such as side slits or micropores).

[0133] The upper and lower porous materials can be considered as frequency-dependent additional impedance Z. p,1 (ω), Z p,2 (ω), the equivalent surface impedance of the overall sandwich structure is:

[0134]

[0135] Corresponding sound absorption coefficient:

[0136]

[0137] By Designed within the 400–800 Hz range (1–2 main peaks), and utilizing a porous layer to provide background absorption in the 800–1000 Hz range, sandwich resonance enhancement in the 400–900 Hz frequency band can be achieved, and the mid-frequency insertion loss IL is improved by approximately 1–2 dB(A) for ordinary porous pavements.

[0138] 3. Resonator array gradient layer form: The upper layer adopts a porous surface layer, the middle layer adopts a 3D printed resonator array layer based on Wills coupling scatterer array structure, and the lower layer adopts a periodic structure or a cavity labyrinth unit structure.

[0139] like Figure 10 As shown, the gradient hierarchical structure is a depth-gradient structure, consisting of a porous surface layer, a porous middle surface layer with embedded resonators, and a lower surface layer mainly composed of resonator arrays from top to bottom, realizing a gradient configuration of "porous - porous + resonant - resonant main layer".

[0140] The gradient hierarchical structure constructs a progressive attenuation path from high frequency to mid frequency to low frequency through a functional gradient in the depth direction. This maintains stable noise reduction performance under different vehicle speeds and contact excitation frequencies, making it particularly suitable for scenarios with high requirements for durability and maintainability, such as heavy-load and expressways. This structure provides full-coverage noise reduction in the 250–1000Hz range, significantly improves low-frequency rolling noise in the 250–500Hz range, and maintains stable absorption of tread meshing noise in the 500–800Hz range, resulting in an overall improvement of 4–7 dB(A) in road environment noise reduction.

[0141] The gradient hierarchy of resonator arrays has the following structural forms:

[0142] (1) Top layer: porous surface layer; middle layer: scatterer array structure based on Wills coupling; bottom layer: periodic structure.

[0143] (2) Top layer: porous surface layer; middle layer: scatterer array structure based on Wills coupling; bottom layer: cavity labyrinth unit structure.

[0144] This invention allows the resonant frequency to be tuned to the target noise frequency band by adjusting the cavity volume, neck diameter (correspondingly adjusting the neck cross-sectional area), and neck length. Multiple resonant units are arranged in an array to achieve wideband noise reduction through frequency coverage.

[0145] The gradient hierarchical structure can be viewed as several resonant layers of different depths stacked in series: the top layer is a porous surface layer, the middle layer is a "porous + embedded resonator", and the bottom layer is the "main resonator layer". The center resonant frequency of the k-th layer resonator is designed to be f. 0,k for:

[0146]

[0147] Each layer of the resonator array is denoted as the k-th layer; A k V is the cross-sectional area of ​​the neck; k For the cavity volume, the geometric parameters satisfy... L eff,k λ is the effective length of the neck; c is the speed of sound.

[0148] The center frequency of the resonator array gradient hierarchy varies with depth, i.e., f 0,k With depth z k Monotonically decreasing (e.g., linear or logarithmic gradient) to achieve sequential control of "high frequency → mid frequency → low frequency" is denoted as an explicit gradient design relationship, as follows:

[0149]

[0150] Among them, f low ≈250Hz,fhigh ≈800~1000Hz.

[0151] In the acoustic equivalent circuit, the surface porous impedance Z p,surf (ω) and the resonant impedance Z of each layer H,k (ω) is approximately connected in series as follows:

[0152]

[0153] Among them, each Z H,k (ω) are all derived from the corresponding (A) k V k ,L eff,k ) Decision. By making {f 0,k Distributed in a gradient within the 250-1000Hz range, it can form continuous and overlapping resonant absorption bands in two key frequency bands: 250-500Hz (main peak of rolling noise) and 500-800Hz (pattern meshing noise), achieving an overall broadband noise reduction effect of 4-7dB(A).

[0154] In summary, this invention enables the resonant frequency to be tuned to the corresponding target noise frequency band by adjusting the cavity volume, neck diameter (corresponding to adjusting the neck cross-sectional area), and neck length.

[0155] The 3D printing material used in this invention is polymer-modified concrete. The mass percentage of each substance in the polymer-modified concrete is as follows: ordinary Portland cement 35-45 wt%, fine aggregate 25-35 wt%, mineral admixture 5-8 wt%, polymer modifier 10-15 wt%, silane coupling agent 1-2 wt%, polycarboxylate superplasticizer 0.15-0.3 wt%, viscosity modifier 0.05-0.15 wt%, accelerator 0.5-1.5 wt%, curing agent 0.6-1.3 wt%, and water 6-8 wt%, with the total content of each substance being 100 wt%.

[0156] The fine aggregate includes three particle size categories, with each particle size category accounting for the following mass percentages: 0.5mm ≤ particle size ≤ 1mm accounts for 10-20 wt%, 0.25mm ≤ particle size < 0.5mm accounts for 30-40 wt%, and 0.075mm ≤ particle size < 0.25mm accounts for 45-55 wt%. The sum of the mass of each particle size category is 100 wt%.

[0157] The mineral admixture comprises, by mass percentage, 40-50 wt% silica fume, 20-30 wt% metakaolin, and 20-30 wt% quartz powder, with the sum of the contents of each substance being 100 wt%.

[0158] The polymer modifier comprises, by mass percentage, 45-55 wt% acrylate emulsion, 25-35 wt% epoxy emulsion, and 10-20 wt% polyurethane dispersion, with a total content of 100 wt%.

[0159] The fine aggregate is limestone, the viscosity modifier is cellulose ether, the coagulant is calcium aluminate, and the curing agent is liquid waterborne polyamide curing agent. All of the above substances were purchased from Beijing Construction Engineering Group Co., Ltd., Aladdin Reagent Co., Ltd., and Sinopharm Chemical Reagent Co., Ltd. The epoxy emulsion and liquid waterborne polyamide curing agent must be used in combination and purchased from the same manufacturer.

[0160] The method for preparing the polymer-modified concrete includes the following steps in sequence:

[0161] Step (1): Weigh each substance according to the designed material ratio and set aside;

[0162] Step (2): Put ordinary silicate cement, silica fume, metakaolin, quartz powder and cellulose ether into a V-type mixer and mix at room temperature for 3-5 minutes at a mixing speed of 200-300 rpm to obtain a dry powder mixture for later use.

[0163] Step (3): Place the acrylate emulsion, epoxy emulsion and polyurethane dispersion into a stirring container and stir at room temperature for 5-8 minutes at a stirring speed of 100-200 rpm to obtain the polymer modifier for later use.

[0164] Step (4): Put the dry powder mixture and fine aggregates of various particle sizes into the mixer and stir at room temperature for 1-3 minutes at a stirring speed of 200-300 rpm to make the dry materials evenly mixed.

[0165] Step (5): Add water and polycarboxylate superplasticizer to the mixer and continue stirring for 2-3 minutes; add polymer modifier to the mixer and continue stirring for 2-3 minutes to ensure that the polymer modifier is evenly dispersed in the whole system; add silane coupling agent to the mixer and continue stirring for 2-3 minutes; add polyamide to the mixer and continue stirring for 2-3 minutes.

[0166] Step (6): Add calcium aluminate to the mixer and continue mixing for 1-3 minutes to obtain polymer-modified concrete.

[0167] The polymer-modified concrete prepared by this invention was tested for various properties after 28 days of standard curing, including: compressive strength of 40-55 MPa, flexural strength of 7-11 MPa, and dry density of 2150-2250 kg / m³. 3The shrinkage rate is 0.018-0.021%, and the plastic viscosity is 20-35 Pa·s. Based on the test results, this polymer-modified concrete is suitable for 3D printing resonators.

[0168] The forming process of the composite road surface of the present invention, consisting of a porous surface layer and a 3D printed resonator array layer, will be described below.

[0169] 1. Installation method

[0170] The 3D-printed resonator array is used as the components of the middle and lower layers, and is arranged in two ways: integral prefabrication or block embedding.

[0171] (1) Overall prefabrication method: The resonator array plate is printed as a whole in the factory or laboratory. The width of the plate is consistent with the width of the lane, and the length is divided into sections according to the transportation and hoisting conditions (such as 2-3m). It is then hoisted directly on site and combined with the roadbed.

[0172] (2) Segmented embedding method: Print into single units or small-sized array units (such as 0.5m×0.5m×0.2m). During the construction of the road base layer, according to the designed array spacing and depth, reserve slots, embed the resonator components one by one, and then fill and fix them with fine-grained concrete or epoxy mortar.

[0173] In 3D-printed composite acoustic pavement structures, the standard dimensions of the individual array modules are the core foundation of the installation design. To balance road module coordination, ease of on-site handling, and space for internal acoustic resonators, the side length of the prefabricated individual array modules is controlled between 400 and 600 mm, and the thickness is controlled between 60 and 100 mm. This size range is suitable for the paving rhythm of urban roads and expressways, and can accommodate resonator unit arrangements in the range of 3×3 to 5×5, while preserving the mechanical load-bearing capacity of the surface structure. For the connection design between the module and the base layer, the depth of the reserved base groove should be the module thickness plus 3 to 8 mm (total depth of 63 to 108 mm) to accommodate leveling mortar or interface bonding layer; the groove spacing in the length and width directions should be 8 to 20 mm larger than the module shape to provide 4 to 10 mm of single-sided installation adjustment space, thereby ensuring smooth module insertion and thermal expansion buffering capacity during actual paving.

[0174] To further improve installation accuracy and subsequent acoustic performance stability, the width of the installation gaps between modules should be strictly controlled within the range of 3–6 mm. Elastic materials should be used for grouting to ensure both sealing and buffering functions of the joints without affecting the overall structure's coupling characteristics at acoustic frequencies. While ensuring structural integrity and module matching, the height difference after module installation should not exceed 2 mm, and the tilt angle should not exceed 1.5° to avoid irregular scattering of sound waves at the cavity opening or loss of excitation efficiency. Furthermore, to ensure the resonant structure is fully excited in the sound field, the bottom openings of all surface modules should maintain a vertical connection with the underlying pre-set resonant cavity. Especially for sandwich structures, a precisely aligned through-hole system should be installed at the bottom of the modules.

[0175] The resonator density inside the module is controlled between 9 and 25 elements per module, typically in a uniform 3×3 to 5×5 array, with the center-to-center spacing between elements controlled between 80 and 150 mm. The volume of the resonant cavity should be limited to 150–300 cm³. 3 The cavity depth is 30–60 mm, the neck opening diameter is controlled at 10–20 mm, and the effective length (including end correction) is between 25–45 mm. This configuration can effectively achieve broadband absorption in the 200–800 Hz range while avoiding mutual interference or frequency overlap failure between cavities. The cavity structure can adopt different forms such as embedded, built-in through-hole, or gradient distributed, and needs to be directionally deployed according to the noise spectrum characteristics to cover the main traffic frequency band.

[0176] 2. Deployment Requirements

[0177] 2.1 Depth of installation: The top surface of the resonant cavity is 40-60mm away from the road surface to ensure direct communication with the porous surface layer.

[0178] 2.2 Array spacing: The horizontal and vertical spacing is generally 50-150mm, depending on the target frequency and design model.

[0179] 2.3 Arrangement: Regular rectangular array, honeycomb arrangement or staggered arrangement are adopted, and different forms correspond to different acoustic frequency band coverage.

[0180] Specifically, in terms of module array deployment, different modes such as rectangular alignment, honeycomb deployment, or staggered deployment can be selected according to the usage scenario.

[0181] Rectangular arrays are best suited for standard road sections, facilitating mechanized assembly, and covering a frequency band concentrated between 200 and 600 Hz. Cellular arrays are suitable for multi-lane roads and acoustic transition zones, offering high density to help balance incident waves from all directions, resulting in a more uniform frequency response and a control range covering 300–800 Hz. Staggered arrays enhance the scattering path through alternating misalignment, providing multi-point resonance capabilities in broadband noise reduction, making them particularly suitable for bridge ramps or special sections with significant noise reduction requirements, extending the coverage bandwidth to 400–1000 Hz. In practical road design, a hybrid array scheme can be selected by combining traffic load, noise spectrum characteristics, and pavement stress distribution in different sections to achieve an optimal layout integrating structure, acoustics, and construction.

[0182] The following is combined Figures 11 to 13 The arrangement of the resonator array in the 3D printed resonator array layer is explained:

[0183] (1) Regular rectangular array: Each resonator array is arranged in a straight line with equal spacing, corresponding to the acoustic frequency band coverage of 200-600Hz.

[0184] like Figure 11 As shown, a regular rectangular array arranges resonator units in a straight line with equal spacing, a layout that facilitates prefabrication and installation. The acoustic behavior of a regular rectangular array is controlled by the unit size and arrangement period, easily exciting local resonances and bandgap effects at specific frequencies, forming relatively clear single-frequency absorption peaks. Limited coupling leads to concentrated resonance but a narrow spectral coverage, while the effective control frequency band of a regular rectangular array is mainly concentrated in the first-order resonant frequency region of the unit itself, such as 250–500 Hz. If the layout density is increased and the size gradient is expanded, it can be extended to 200–600 Hz. Regular rectangular arrays are suitable for controlling the dominant low-frequency (tire rolling fundamental frequency) noise at specific vehicle speeds, and are suitable for scenarios with high requirements for construction efficiency and modularity, such as sound-absorbing panels for highway slopes.

[0185] (2) Honeycomb layout: Each resonator array adopts a hexagonal close-packed arrangement, corresponding to the acoustic frequency band coverage of 300-800Hz.

[0186] like Figure 12As shown, the honeycomb arrangement employs a hexagonal close-packed pattern to enhance the space filling rate (theoretically up to 90.7%), improving structural mechanical stability while strengthening near-field coupling between resonant units. This coupling facilitates local bandgap widening and multi-frequency resonance superposition, causing multiple absorption peaks to split at different frequencies, thus improving the bandwidth response from low to mid frequencies. The honeycomb array can form multiple peak width superposition regions in the 300–800 Hz range, providing higher absorption efficiency per unit volume, especially when structural thickness is limited. The honeycomb arrangement is suitable for high-traffic areas (such as sections with heavy truck traffic) or for use as a substrate material for urban overpasses and noise barriers requiring high structural stability and strong sound absorption.

[0187] (3) Staggered arrangement: Adjacent resonator arrays are arranged in a staggered manner, corresponding to the acoustic frequency band coverage of 400-1000Hz.

[0188] like Figure 13 As shown, the staggered arrangement (i.e., oblique array) breaks the periodic arrangement, creating a misaligned relationship between adjacent units, effectively disrupting the symmetrical reflection path of the incident sound wave, resulting in a multimodal resonant response superposition in the sound absorption behavior. The staggered arrangement introduces perturbations and nonlinear propagation paths, generating a wider sound energy dissipation bandwidth in the mid-to-high frequency range (e.g., 400–1000 Hz). Because the staggered arrangement suppresses the "Bragg bandgap jump" caused by the periodic array, its absorption spectrum is more continuous and without significant gaps. The staggered arrangement is suitable for handling complex mid-frequency spectral components such as vehicle patch noise and meshing noise in scenarios such as urban commuter roads and urban expressways, and also helps to construct multi-frequency flexible matching sound-absorbing pavement structures.

[0189] 2.4 Opening Requirements: The neck of the resonator must be connected to the upper surface layer, with the opening facing vertically upwards, and must be protected from blockage by asphalt mixture or polyurethane grout during construction. If necessary, a high-temperature resistant plug can be used to seal the opening during paving and then removed after compaction.

[0190] 3. Top layer paving

[0191] After the resonator array is installed, a porous asphalt mixture (porosity ≥18%) or a porous polyurethane elastic mixture with a thickness of 40-60mm is laid on top, forming a porous surface layer. During construction, the paving temperature and compaction pressure are controlled to avoid damage to the resonator openings due to excessive temperature or pressure. This invention employs a process of initial compaction with lightweight steel wheels followed by secondary compaction with rubber wheels to ensure density and connectivity.

[0192] The specific requirements for paving temperature and compaction pressure during the construction of the top layer are as follows:

[0193] (1) During the prefabrication stage in the factory, the printing environment temperature should be controlled between 20 and 30°C to avoid the decrease in fluidity of polymer-modified concrete and insufficient interlayer bonding caused by low temperature. Simultaneously, the relative humidity should be maintained at 50-70% to reduce the risk of early surface cracking. The thickness of a single layer should be controlled between 5 and 10 mm, and the overlap time between adjacent layers should not exceed 5-10 minutes to ensure the integrity of the structure. After printing, the concrete should be left to cure for at least 48 hours until the strength reaches 10 MPa or higher before demolding and transportation. The curing temperature should be maintained at 20-25°C to avoid excessive moisture evaporation due to high temperature, which would affect the formation of the porous structure. At the same time, the ambient humidity should be maintained above 80% to promote uniform hydration within the concrete.

[0194] (2) During the on-site installation phase, in order to achieve efficient connection of the prefabricated structure, the size of the pre-reserved groove in the base should be precisely matched with the actual size of the prefabricated 3D printed concrete panel. For example, for a typical 500×500×80mm prefabricated block, the length and width of the pre-reserved groove should be 5-8mm larger than the panel size to adjust the installation position; the depth should be the surface layer thickness plus 5mm to accommodate the leveling mortar.

[0195] During installation, the pressing pressure should be between 0.2 and 0.4 MPa. Compaction should be achieved using mechanical assistance or manual hammering. The use of vibratory compaction equipment is strictly prohibited to avoid damaging the internal pores of the top layer. Before installation, apply polymer-modified mortar or interface agent to the contact surfaces of the base and surface layers to improve bonding strength and long-term service performance. After assembly, seal the surrounding gaps with elastic sealant or caulking putty, using materials that match the color and elastic modulus of the concrete surface to prevent cracking, warping, or acoustic failure due to thermal expansion and contraction.

[0196] (3) To ensure the acoustic function of the structure, the assembly accuracy should be strictly controlled. After the upper layer is laid, its overall flatness error should not exceed 2mm to prevent local abrupt changes from causing a reduction in sound wave scattering and absorption efficiency. At the same time, the installation tilt angle should be controlled within 1.5° to ensure the normal working angle of the Helmholtz resonator.

[0197] In the coupling design of the upper layer and the resonant structure, it should be ensured that the resonator opening is completely connected to the porous concrete surface or the sound guide channel. If a sandwich structure is used, it is recommended to pre-set a vertical through hole at the bottom of the upper layer that communicates with the resonator cavity below, so as to realize a continuous sound energy coupling path from the wheel-road surface-cavity and maximize the noise reduction effect.

[0198] 4. Structural connection and fixing

[0199] To ensure the integrity of the composite pavement, the 3D-printed resonator array layer and the base layer can be fixed in the following ways:

[0200] (1) Integral prefabricated plate: The 3D printed resonator array layer is manufactured by integral printing, and the width of the plate is the same as the width of the lane; the bottom is provided with a rough surface or prefabricated groove to form a mechanical interlock with the cement base.

[0201] (2) Embedded Units: The 3D printed resonator array layer is divided into multiple embedded units, which are assembled and embedded according to the pre-reserved slots according to the designed array spacing and depth. After embedding, the slots are backfilled and sealed with cement mortar or polymer mortar to prevent the units from loosening or shifting. The gaps between the embedded units are filled with elastic material.

[0202] The interface between the resonator components and the surface layer is treated, for example, by applying an interface agent, to enhance adhesion and prevent interlayer delamination.

[0203] 5. Construction quality requirements

[0204] The flatness deviation of the resonator array layout shall not exceed ±2mm; the allowable deviation of the opening position shall not exceed ±1mm; after the construction of the upper porous surface layer is completed, the opening of the resonator cavity shall be confirmed to be unobstructed by vacuum method or compressed air method.

[0205] Furthermore, the 3D resonator provided by this invention is effective not only for low-frequency noise but also for mid-to-high-frequency noise, specifically including the following three forms:

[0206] 1. Small-sized independent resonant unit array

[0207] The volume of the resonator unit is 20–50 cm³. 3 The neck diameter is 5-8 mm and the neck length is 5-10 mm. These elements are arranged in a high-density array using 3D printing, with a unit spacing of 5-10 mm. The resonant frequency of this design is concentrated in the 800-1400 Hz range, used to absorb the mid-to-high frequency waves generated by tire tread meshing.

[0208] 2. Multi-aperture high-coupling resonant cavity

[0209] The resonator has 3 to 5 small openings with a diameter of 3 to 5 mm on the top to enhance multi-directional acoustic energy coupling, improve the excitation efficiency of incident sound waves in the mid-frequency band, and form an extended absorption bandwidth in the 700 to 1200 Hz frequency band.

[0210] 3. Microperforated surface coating structure

[0211] Adding a micro-perforated covering layer with a pore size of 1-2 mm, a porosity of 10-15%, and a thickness of 3-5 mm to the surface of the resonator can effectively adjust the incident acoustic impedance, achieve critical coupling, stabilize the absorption performance at 1000-1500 Hz, and improve the mid-frequency sound absorption efficiency.

[0212] The acoustic performance of composite pavement structures was tested and optimized under laboratory conditions, mainly including the following aspects:

[0213] 1. Acoustic performance testing

[0214] Sound absorption coefficient measurement: The sound absorption coefficient of the composite road test specimen in the frequency range of 100Hz to 2000Hz was measured using an impedance tube (standing wave tube method or PU probe method) to evaluate the frequency response characteristics after the porous surface layer is coupled with the 3D resonator array layer.

[0215] Transmission loss test: In a reverberation chamber or anechoic chamber, using the arrangement of sound source and receiver, the transmission loss curve of the composite specimen under different resonator parameters is tested to clarify its reduction effect on the target noise frequency band.

[0216] Noise reduction performance calculation: Based on the sound pressure level difference between the reference specimen and the composite road test specimen, the noise reduction performance is calculated using the following formula:

[0217] ΔL=L ref -L sample (12)

[0218] Among them, L ref The noise sound pressure level (dB) of a typical porous road surface specimen; L sample ΔL represents the noise sound pressure level (dB) of the composite road test specimen; ΔL represents the noise reduction performance (dB).

[0219] Table 1 shows the acoustic performance comparison data. This invention, by adjusting the relevant parameters of the resonant cavity, can tune the resonant frequency to the corresponding target noise frequency band. Based on the cavity type (cylindrical, rectangular, and spherical) and parameters (cavity height H, cavity diameter / width D / W, neck length L, neck diameter a, array spacing S, and material density ρ), the acoustic performance data (peak frequency f0, absorption bandwidth BW, and peak absorption coefficient α) are output. max These acoustic performance data are used to characterize the noise reduction effect.

[0220] Table 1 Comparison of Acoustic Performance Data

[0221]

[0222] 2. Result Optimization

[0223] By comparing experimental results of different resonator geometric parameters, array spacing, and material ratios, the impact of these parameters on noise reduction bandwidth and amplitude was analyzed. Key parameters such as resonant cavity volume, neck diameter, and cavity opening morphology were further optimized to determine a design scheme suitable for typical road noise spectra in typical scenarios. Table 2 shows the optimization suggestions based on adjusting cavity parameters, cavity type, array spacing, and aperture ratio.

[0224] Table 2 Results and Optimization Suggestions

[0225]

[0226] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," and "some examples" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0227] It will be readily understood by those skilled in the art that this invention includes any combination of the above-described contents, specific embodiments, and the parts shown in the accompanying drawings. Due to space limitations and for the sake of brevity, not all of these combinations have been described in detail. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A 3D-printed resonator array layer low-noise road surface structure, the road surface structure comprising, from top to bottom, a surface layer, a base layer, and a subbase layer, characterized in that, The surface layer consists of an upper layer, a middle layer, and a lower layer arranged from top to bottom; wherein, the upper layer is a porous surface layer, the middle layer is a 3D printed resonator array layer, and the lower layer is either a porous surface layer or a 3D printed resonator array layer. The structure of the 3D printed resonator array layer includes: a periodic structure, a scatterer array structure based on Wills coupling, and a cavity labyrinth unit structure. The periodic structure includes: an elastic ultrathin surface layer made of porous medium arranged from top to bottom and a plurality of adjacent resonator cavities, wherein the elastic ultrathin surface layer made of porous medium and the resonator cavities together form a composite surface structure; each resonator cavity has an opening at the top to communicate with the elastic ultrathin surface layer made of porous medium. The scatterer array structure based on Wills coupling includes: a porous medium and multiple scattering functional units embedded in the porous medium; wherein, the multiple scattering functional units are arranged in an array within the porous medium, and the interior and exterior surfaces of each scattering functional unit form a connected scattering structure to form a resonator cavity and communicate with the porous medium. The cavity labyrinth unit structure includes: an elastic ultrathin surface layer composed of porous medium arranged from top to bottom and an acoustic metastructure array composed of multiple U-shaped functional units; the multiple U-shaped functional units are interconnected and form multiple interconnected cavities in a labyrinth shape to form a resonator cavity; each U-shaped functional unit has an opening at the top to communicate with the elastic ultrathin surface layer composed of porous medium; The surface layer has one of the following structures: (1) Multilayer resonator array combination form: the upper layer adopts a porous surface layer, the middle layer and the lower layer adopt a 3D printed resonator array layer that is connected vertically; wherein, the middle layer is stacked with one or more 3D printed resonator array layers to form a vertical multilayer resonator system; (2) Sandwich form of resonator array: the upper layer is a porous surface layer, the middle layer is a 3D printed resonator array layer, and the lower layer is a porous surface layer; wherein, the top and bottom of each resonator cavity in the middle layer are provided with openings; (3) Resonator array gradient layer form: the upper layer adopts a porous surface layer, the middle layer adopts a 3D printed resonator array layer based on Wills coupling scatterer array structure, and the lower layer adopts a 3D printed resonator array layer with periodic structure or cavity labyrinth unit structure.

2. The 3D-printed resonator array layer low-noise road surface structure according to claim 1, characterized in that, The resonator cavity of the periodic structure can be one of the following shapes: cylindrical cavity, rectangular cavity, and spherical cavity.

3. The low-noise road surface structure with 3D-printed resonator array layer according to claim 1, characterized in that, Each of the aforementioned scattering functional units adopts a cylindrical structure, with multiple interconnected cavities formed inside and on the surface of the cylindrical structure, scattering outward from the center.

4. The 3D-printed resonator array layer low-noise road surface structure according to claim 1, characterized in that, The resonator cavity of the periodic structure is further provided with openings at the bottom or side to connect with the porous surface layer or resonator array below or to the side. The bottom or side of the zigzag functional element of the cavity labyrinth unit structure is further provided with an opening to connect with the porous surface layer or resonator array below or to the side.

5. The 3D-printed resonator array layer low-noise road surface structure according to claim 1, characterized in that, The resonant frequency f of the multilayer resonator array combination 0,k for: Each layer of the resonator array is denoted as the k-th layer, where k = 1, 2, ..., N, and N is the layer number; A k V is the cross-sectional area of ​​the neck; k L represents the volume of the cavity. eff,k λ is the effective length of the neck; c is the speed of sound.

6. The 3D-printed resonator array layer low-noise road surface structure according to claim 1, characterized in that, In the sandwich configuration of the resonator array, the resonant frequency f is achieved when openings are provided at both the top and bottom of each individual resonator cavity. 0,i for: Where i represents the i-th resonant cavity in the resonator array layer; A i V is the cross-sectional area of ​​the neck; i L represents the volume of the cavity. eff,i λ is the effective length of the neck; c is the speed of sound.

7. The 3D-printed resonator array layer low-noise road surface structure according to claim 1, characterized in that, In the sandwich configuration of the resonator array, the resonant frequency is achieved when openings are provided on the top, bottom, and sides of each individual resonator cavity. for: Where i represents the i-th resonant cavity in the resonator array layer; V i c is the volume of the cavity; c is the speed of sound; The effective neck cross-sectional area represents the total area of ​​the open region that can participate in acoustic wave coupling. A 顶 A represents the area of ​​the opening on the upper surface of the neck, i.e., the area of ​​the hole connecting the top of the resonator to the outside world; 底 A represents the area of ​​the opening at the bottom of the neck, i.e., the area of ​​the opening at the bottom of the resonator that connects downwards or allows for ventilation; 侧 This refers to the area of ​​the lateral opening in the neck, which appears in resonators with side-hole structures or perforated housings; The effective length of the neck. L i ΔL is the basic effective length of the resonator cavity, i.e., the straight-line length without considering structural disturbances; 顶 The additional sound path length caused by the top connection; ΔL 底 The additional sound path length caused by disturbances in the bottom structure or openings; ΔL 侧 This refers to the additional sound path length caused by the opening in the side wall.

8. The 3D-printed resonator array layer low-noise road surface structure according to claim 1, characterized in that, The resonant frequency f in the gradient hierarchy of the resonator array 0,k for: Each layer of the resonator array is denoted as the k-th layer; A k V is the cross-sectional area of ​​the neck; k For cavity volume, L eff,k λ is the effective length of the neck; c is the speed of sound.

9. The 3D-printed resonator array layer low-noise road surface structure according to claim 1, characterized in that, The 3D-printed resonator array layer can be fixed to the base layer in the following ways: (1) Integral prefabricated plate: The 3D printed resonator array layer is manufactured by integral printing, and the width of the plate is the same as the width of the lane; the bottom is provided with a rough surface or prefabricated groove to form a mechanical interlock with the cement base; (2) Embedded Units: The 3D printed resonator array layer is divided into multiple embedded units, which are combined and embedded according to the pre-reserved slots of the designed array spacing and depth. After embedding, the units are backfilled and sealed with cement mortar or polymer mortar to prevent the units from loosening or shifting. The gaps between the embedded units are filled with elastic material.

10. The 3D-printed resonator array layer low-noise road surface structure according to claim 1, characterized in that, The resonator array arrangement of the 3D printed resonator array layer includes: Regular rectangular array: Each resonator array is arranged in a straight line with equal spacing, corresponding to the acoustic frequency band coverage of 200-600Hz; Honeycomb layout: Each resonator array adopts a hexagonal close-packed arrangement, corresponding to the acoustic frequency band coverage of 300-800Hz; Interleaved arrangement: Adjacent resonator arrays are arranged in a staggered manner, corresponding to the acoustic frequency band coverage of 400-1000Hz.

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