A shock-absorbing and sound-insulating structure having a phononic crystal-like porous ceramic plate

Abstract

The application discloses a shock-absorbing and sound-insulating structure with a phonon-like crystal porous ceramic plate, and belongs to the technical field of shock-absorbing and sound-insulating structures. The shock-absorbing and sound-insulating structure comprises a porous ceramic base body with an interpenetrating net-like pore structure in the inside, a soft polymer material elastic layer attached to the wall surface of the interpenetrating net-like pore, and a hard polymer material mass core filled in the inside of the soft elastic layer. The application not only can form a low-frequency band gap to block the propagation of vibration, but also can efficiently convert a large amount of kinetic energy into heat energy dissipation in the severe shear deformation of the soft polymer material; meanwhile, the continuous three-dimensional interpenetrating net-like structure not only gives the structure better overall bearing stiffness, but also widens the low-frequency shock-absorbing frequency band through the strong modal coupling between the pores.

Description

Technical Field

[0001] This invention relates to the field of building vibration reduction and acoustic metamaterials technology, and in particular to a vibration reduction and sound insulation structure of a phononic crystal porous ceramic plate with an interconnected grid structure. Background Technology

[0002] In modern buildings and residential environments, low-frequency structural sound transmission caused by floor impacts (such as falling heavy objects, dragging furniture, and people running and jumping) is a major source of noise pollution affecting the acoustic environment. Traditional floor vibration reduction and isolation technologies often employ a "floating floor" process, which involves laying elastic pads such as rubber, glass wool, or polyurethane foam on the structural floor slab. However, this type of pad, based on a traditional mass-spring system, has significant drawbacks: on the one hand, it has extremely poor isolation effect on low-frequency impact vibrations below 100Hz, and may even easily induce system resonance at certain frequencies; on the other hand, traditional elastic materials are prone to creep and aging under long-term static loads, leading to a significant decline in sound insulation performance over service life.

[0003] In recent years, the development of acoustic metamaterials, especially locally resonant phononic crystals, has provided new ideas for breaking the mass law and achieving low-frequency sound insulation. However, most existing thin-film acoustic metamaterials rely on applying prestress to the thin film to adjust the resonant frequency. In long-term practical engineering service, these prestressed structures are prone to losing their original mechanical and acoustic properties due to material relaxation, creep, and aging, making reliability difficult to guarantee. Therefore, how to abandon complex mechanical prestress and directly utilize the intrinsic properties and natural three-dimensional porosity of materials to develop a floor slab structure that combines high load-bearing capacity, long-term stability, and full-frequency noise reduction is a pressing technical challenge. Summary of the Invention

[0004] To overcome the shortcomings and deficiencies of existing technologies, the purpose of this invention is to provide a vibration-damping and sound-insulating structure of a porous ceramic plate with an interconnected grid structure resembling a phononic crystal. This invention breaks through the limitations of traditional floating floor slabs that rely on a single elastic cushion layer for sound insulation. It utilizes porous ceramic with three-dimensional interconnected pores as a natural framework, and incorporates soft and hard dual-component polymer materials internally. Without relying on any external prestress, it constructs an in-situ grown, locally resonant phononic crystal-like system, achieving a high degree of unity between low-frequency shock resistance and vibration reduction and full-frequency sound absorption and insulation.

[0005] The technical solution provided by this invention is as follows:

[0006] A vibration damping and sound insulation structure comprising a phonon crystal-like porous ceramic plate, the vibration damping and sound insulation structure comprising:

[0007] A porous ceramic matrix with an internal interconnected network of pores is used to provide macroscopic structural compressive stiffness.

[0008] The soft polymer elastic layer attached to the wall of the interconnected mesh pores serves as a viscoelastic medium connecting the mass core and the matrix;

[0009] And, a mass core of hard polymer material filling the inner side of the soft elastic layer.

[0010] This invention overcomes the shortcomings of existing technologies by providing a vibration-damping and sound-insulating structure for porous ceramic plates with an interconnected grid structure, resembling phononic crystals. It aims to overcome the defects of traditional floating floor slabs, such as poor low-frequency sound insulation and the tendency of elastic cushioning layers to creep and age under long-term static loads. This structure uses porous ceramics with three-dimensional interconnected pores as a natural load-bearing matrix. Soft polymer materials (elastic layers) are sequentially attached to the grid pore walls from the outside in, and then filled with hard polymer materials (mass cores), cleverly constructing a localized resonant phononic crystal-like microstructure unit of "matrix-elastic layer-mass core". When subjected to external impact, the hard core and soft elastic layer within this composite system generate strong local resonance. This not only creates a low-frequency bandgap to block vibration propagation but also efficiently converts a large amount of kinetic energy into heat dissipation during intense shear deformation via the soft polymer material. Simultaneously, the continuous three-dimensional interconnected mesh not only provides the structure with better overall load-bearing stiffness but also broadens the low-frequency damping band through strong modal coupling between pores. Furthermore, the pores within the structure that are not yet fully filled can further absorb mid-to-high frequency airborne sound through the viscous-thermal conduction effect between air molecules and pore walls. By directly utilizing the inherent intrinsic properties of the material to achieve vibration reduction and sound insulation, this invention successfully creates a highly efficient metamaterial composite system with long-term mechanical stability, no aging risks, and integrating low-frequency impact damping and sound absorption / insulation functions.

[0011] The beneficial effects of this invention after adopting the above technical solution are as follows:

[0012] (1) Low-frequency high-efficiency vibration reduction: When the floor slab is impacted, the hard core and soft elastic layer inside the structure will generate strong local resonance. At a specific anti-resonance frequency point, the huge reverse inertial force generated by the movement of the hard core and the external excitation force on the matrix reach a dynamic mechanical equilibrium, which greatly suppresses the displacement response of the macroscopic matrix and forms a low-frequency band gap to block the propagation of solid waves. At the same time, the high viscoelasticity of the soft polymer material efficiently converts a large amount of impact kinetic energy into heat energy dissipation during severe shear deformation.

[0013] (2) Advantages of topological continuity and multiple couplings: Compared with scattered isolated cells, the porous ceramic matrix with continuous interconnected three-dimensional grid pores of the present invention provides better overall load-bearing stiffness. More importantly, the strong modal coupling and multiple scattering of sound waves between continuous pores greatly broaden the bandwidth of low-frequency vibration reduction, enabling the structure to exhibit excellent sound insulation performance over a wider frequency range.

[0014] (3) Material intrinsic properties drive long-term stability without aging risks: This structure directly utilizes the inherent properties of the material (core-shell structure) to achieve vibration reduction and sound insulation. It effectively avoids the defects of traditional floating floor slabs that rely on elastic cushioning for vibration reduction, which are prone to loosening and aging during use, and ensures mechanical stability and engineering durability throughout the entire building life cycle.

[0015] (4) Multi-physics field synergistic noise reduction across the entire frequency band: In addition to the low-frequency vibration reduction brought about by local resonance, the interconnected open structure of the matrix itself can further absorb mid-to-high frequency airborne sound by utilizing the viscosity effect and thermal conduction effect between air molecules and rough pore walls. This forms a highly efficient metamaterial that integrates low-frequency shock resistance and vibration reduction with mid-to-high frequency sound absorption and insulation. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the interconnected mesh pore structure inside the porous ceramic matrix of the present invention;

[0017] Figure 2 This is a partially enlarged schematic diagram of the local resonance structure of the "matrix-elastic layer-mass core" type phononic crystal of the present invention;

[0018] Figure 3 The phononic crystal porous ceramic plate of this invention was simulated in COMSOL Multiphysics 6.3 to simulate the unit cell structure of "matrix-elastic layer-mass core";

[0019] Figure 4 A simplified schematic diagram simulating the "elastic layer-mass core" inside the phononic crystal porous ceramic plate of this invention;

[0020] Figure 5 A simplified schematic diagram simulating the interpenetrating mesh-like phonon crystal structure inside the porous ceramic plate of the present invention;

[0021] Figure 6 This is a complete structural schematic diagram of the phonon crystal porous ceramic plate of the present invention in COMSOL Multiphysics 6.3 simulation.

[0022] Figure 7 This is a comparison diagram of the sound pressure level of the structure of the present invention and a conventional concrete slab under a specified acceleration. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0024] This invention discloses a vibration damping and sound insulation structure for a phonon crystal-like porous ceramic plate with an interconnected mesh structure, such as... Figure 1 , Figure 2 As shown, the vibration damping and sound insulation structure includes:

[0025] A porous ceramic matrix A with an internal interconnected network of pores is used to provide macroscopic structural compressive stiffness.

[0026] The soft polymer elastic layer B, attached to the wall of the interconnected mesh pores, serves as a viscoelastic medium connecting the mass core and the matrix.

[0027] And, the mass core C of the hard polymer material filled inside the soft elastic layer.

[0028] In actual engineering, this structure is laid flat on a standard load-bearing floor slab in the form of a plate of a certain thickness. The microstructure of this vibration damping and sound insulation structure is as follows: porous ceramics with three-dimensional interconnected voids form a solid load-bearing matrix, with a layer of low-modulus, high-loss factor soft polymer elastic material tightly wrapped around the pore walls, while the center of the pores is filled with a high-density hard polymer mass core.

[0029] In this embodiment of the invention, the design process of the vibration damping and sound insulation structure is as follows: First, in COMSOL Multiphysics 6.3, a simplified design of a unit cell with interpenetrating pores is implemented, such as... Figure 3 As shown, Figure 3 The blue area represents a porous ceramic matrix, the yellow area represents soft polyurethane, and the red area represents rigid polyurethane. Then, the internal structure is designed, such as... Figure 4 The body-centered cubic lattice unit shown is Figure 4 The gray area represents soft polyurethane, and the blue area represents hard polyurethane. Next, an interpenetrating phonon crystal plate, internally composed of both soft and hard polyurethane materials, is assembled using an array, such as... Figure 5 As shown. Then, a concrete slab is added below the interpenetrating phonon crystal plate to obtain the vibration damping and sound insulation structure of the present invention, as shown. Figure 6 As shown.

[0030] A specified acceleration of 0.1 m / s² was applied to the center of a phononic crystal-like porous ceramic plate, and the sound pressure level (SPL) radiated into the air below was simulated. A comparative simulation replaced the phononic crystal-like porous ceramic plate with a pure concrete plate of the same size, and the same specified acceleration of 0.1 m / s² was applied to its center, simulating the SPL radiated into the air below. In the COMSOL Multiphysics acoustic-structure interaction simulation experiment, to verify the acoustic performance of the novel structure, the model applied the same specified acceleration of 0.1 m / s² to the center of both a 4 cm thick conventional pure concrete plate and a phononic crystal-like porous ceramic plate internally composited with soft and hard polyurethane materials, and the SPL radiated into the air below was compared. Figure 7The curve shows that the phononic crystal-like porous ceramic plate (red line) has an extremely deep sound pressure level trough at about 2500 Hz (dropping sharply to about 11~12 dB), which directly proves that the hard core and soft elastic layer inside the micropores generate strong local resonance when stimulated. At this specific anti-resonance frequency point, the huge reverse inertial force generated by the movement of the hard core and the external excitation force on the matrix reach a dynamic mechanical equilibrium, which greatly suppresses the displacement response of the macroscopic matrix, thus successfully forming a band gap to block the propagation of solid waves. After crossing the low-frequency resonance region, within a wide frequency range of 3000–5000 Hz, the radiated sound pressure level of this type of phononic crystal porous ceramic plate is steadily suppressed to an extremely low level of 20–25 dB. This is not only due to the high viscoelasticity of the soft polymer material, which efficiently converts a large amount of impact kinetic energy into heat dissipation during intense shear deformation, but also because the interconnected pore structure of the porous ceramic matrix utilizes the viscous-thermal conduction effect between air molecules and pore walls to further absorb mid-to-high frequency airborne sound waves. Through the ingenious integration of the aforementioned local resonance mechanism and porous dissipation mechanism, this structure ultimately exhibits highly efficient metamaterial properties in simulations, combining low-frequency impact resistance and vibration reduction with full-frequency sound absorption and insulation.

[0031] The working principle of this structure lies in the synergy of multiple physical mechanisms. When the floor surface is subjected to broadband impacts from friction between tables and chairs or falling heavy objects, a huge amount of transient kinetic energy is transferred downwards: First, in the low-frequency range, countless "hard mass cores" within the interconnected grid resonate locally under the connection of the "soft elastic layer." Near the anti-resonance point, the inertial force generated by the internal mass cores and the excitation force transmitted to the porous ceramic matrix from the outside achieve dynamic mechanical equilibrium, and the macroscopic displacement is rapidly attenuated. In this intense relative motion, the highly viscoelastic soft elastic layer undergoes extreme shear deformation, converting a large amount of impact kinetic energy into heat dissipation. Second, due to the three-dimensional interconnectedness of the grid, this vibration reduction effect is not limited to a single pore. The continuous skeleton and soft elastic layer interface induce strong multi-wave scattering and modal coupling, significantly broadening the vibration reduction frequency band. Finally, for mid-to-high frequency airborne sound, the micropores that are not yet fully filled in the structure form a complex acoustic labyrinth, achieving excellent sound absorption through the thermal viscosity loss of air molecules.

[0032] It is worth emphasizing that the generation and maintenance of the phonon crystal bandgap in this embodiment are entirely based on the intrinsic mechanical parameter differences between porous ceramics and two-component polymer materials. Since no external pre-tensioning force is required, this structure not only exhibits excellent load-bearing stiffness similar to solid porous ceramics when subjected to long-term static building loads above, but also fundamentally eliminates the risk of stress relaxation and aging failure, thus possessing extremely high engineering reliability.

[0033] In practical engineering, given specific performance requirements and parameter settings, the vibration damping and sound insulation structure of this invention can be manufactured using existing conventional and mature processes. For example, the manufacturing process of the vibration damping and sound insulation structure of this invention specifically includes the following steps:

[0034] (1) The manufacturing process of porous ceramics is to impregnate ceramic slurry with organic foam, dry it, and then burn off the organic foam carrier at high temperature to form a porous structure, thereby obtaining porous ceramics. Its unique feature is that it uses the special structure of the open-cell three-dimensional network skeleton of the organic foam to uniformly coat the prepared slurry onto the organic foam network, and the pores obtained after burning off the organic foam are mesh-like.

[0035] (2) Then, the porous ceramic structure is first immersed in soft polyurethane and then taken out. At this time, a layer of soft polyurethane about 1 mm thick will be left on the porous ceramic frame. After the polyurethane dries, it is rinsed again. At this time, the thickness of the soft polyurethane is generally 2 mm. After it dries, the whole structure is placed in the mold and poured into the hard polyurethane liquid material. After curing, the material is formed.

[0036] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A vibration damping and sound insulation structure with a porous ceramic plate resembling a phonon crystal, characterized in that, The vibration damping and sound insulation structure includes: A porous ceramic matrix with an internal interconnected network of pores is used to provide macroscopic structural compressive stiffness. The soft polymer elastic layer attached to the wall of the interconnected mesh pores serves as a viscoelastic medium connecting the mass core and the matrix; And, a mass core of hard polymer material filling the inner side of the soft elastic layer.

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