Elastic wave filter based on annular cylindrical shell thin plate structure and implementation method thereof

Abstract

The invention discloses an elastic wave filter based on an annular cylindrical shell thin plate structure and an implementation method thereof. The elastic wave filter comprises a homogeneous elastic thin plate and a resonance structure of a hollow annular cylindrical shell. By introducing an annular cylindrical shell resonance structure, efficient filtering and frequency selective control of elastic waves are realized. The filter has the advantages of high frequency selectivity, wide bandwidth control, construction flexibility, high reliability and the like, and is suitable for the fields of signal processing, sensing and the like.

Description

Technical Field

[0001] The present invention relates to a technology in the field of elastic wave filters, in particular to an elastic wave filter based on an annular cylindrical shell thin plate structure and a method for realizing the same. Background Art

[0002] Elastic wave filtering thin plate devices have important application value in fields such as vibration signal recognition and structural health monitoring. Existing periodic array thin plate structure filtering devices can achieve band gap theoretical frequency band selection, but they have problems such as complex structure, large size, low filtering accuracy and efficiency, and cannot accurately measure vibration frequency and mode. Summary of the Invention

[0003] In response to the above-mentioned deficiencies in the prior art, the present invention proposes an elastic wave filter based on an annular cylindrical shell thin plate structure and an implementation method thereof. By precisely constructing the resonance of the hollow cylindrical shell, the elastic wave response of the homogeneous thin plate is controlled within the hollow cylindrical shell, achieving elastic wave control with high sensitivity and high filtering efficiency while having an extremely simple and compact structure and easy processing.

[0004] The present invention is achieved through the following technical solutions:

[0005] The invention relates to an elastic wave filter based on an annular cylindrical shell thin plate structure, comprising a resonance structure of a homogeneous elastic thin plate and a hollow annular cylindrical shell.

[0006] The wall thickness of the hollow annular cylindrical shell is obtained by reverse construction using a discrete oscillator construction method, specifically including:

[0007] 1) The construction method of the discrete oscillator is as follows: , , where: H p is the height of the equivalent oscillator, f is the filtering frequency, E is the elastic modulus of the material, R t is the radius of the equivalent discrete oscillator, that is, the wall thickness of the hollow cylindrical shell is 2R t , is the zero-order Bessel function, N is the number of oscillators after the hollow cylindrical shell is discretized into cylinders, E is the Young's modulus of the metal material parameter, is the density of the hollow cylindrical shell thin plate elastic wave filter, D is the bending stiffness of the homogeneous thin plate structure, and h is the thickness of the homogeneous thin plate structure.

[0008] 2) According to the limiting conditions of the elastic wave filter frequency, the fixed modal control parameter φ, the elastic wave filter frequency f, the material and geometric parameters are determined and the corresponding equivalent vibrator height H is obtained. p , specifically: ,in: is the φ-order Bessel function, k0 is the wave number, and R is the radius of the hollow cylindrical shell.

[0009] 3) According to the enhancement of the equivalent stiffness due to the coupling effect between discrete elements after the discrete model evolves to the hollow cylindrical shell, the equivalent oscillator height H is modified. p In order to keep the equivalent resonant frequency unchanged, the equivalent oscillator height H around the column p By sweeping the parameters, elastic wave bound states with real eigenfrequencies and high energy density are obtained to construct an optimized elastic wave filter.

[0010] The reverse structure is preferably verified by applying a numerical simulation method, that is, establishing a corresponding elastic wave filter entity model in the numerical simulation software, verifying the arrangement radius R of the resonant cylinder ring under the specified control requirements, and the modal control parameter f sim The errors of f and f are within an acceptable range, and dual-frequency incident waves are applied to the elastic wave filter in the time domain module to compare the filtering efficiency and filtering frequency of the bare plate and hollow cylindrical shell thin plate elastic wave filters.

[0011] The present invention relates to an application based on the elastic wave filter, which is used for thin plate vibration characteristic identification, elastic wave filtering and sensing.

[0012] Technical Effects

[0013] The present invention is based on a method for constructing elastic wave bound states, unifying the elastic wave bound state frequency, mode, thin plate geometry and material parameters into a discrete oscillator construction method. Through a compact and minimalist structure, high-quality factor low-scattering elastic wave localized state regulation of a specified frequency and a specified mode is achieved in a specified area of ​​the thin plate. The low-scattering bound state can be used to construct an elastic wave filter with a thin plate structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention;

[0015] In the figure: homogeneous thin plate structure 1, hollow cylindrical shell 2;

[0016] Figure 2 for Figure 1 Top view;

[0017] In the figure: R is the radius of the hollow cylindrical shell structure;

[0018] Figure 3 The evolution relationship between the quality factor of the homogeneous thin plate structure and the height of the hollow cylindrical shell in the numerical simulation of the embodiment;

[0019] Figure 4 For example Figure 3 Out-of-plane displacement field of hollow cylindrical shell-uniform thin plate structure under medium maximum quality factor;

[0020] Figure 5 Response spectra of the bare plate and hollow cylindrical shell thin plate filters in the embodiment. DETAILED DESCRIPTION

[0021] like Figure 1 As shown, this embodiment relates to an elastic wave filter based on an annular cylindrical shell thin plate structure, including: a homogeneous thin plate structure 1 and a hollow cylindrical shell 2, wherein: the hollow cylindrical shell 2 takes the center of the homogeneous thin plate structure 1 as the center of the circle, and the radius of the hollow cylindrical shell is R. The vibration of the homogeneous thin plate structure 1 is controlled by the resonance of the hollow cylindrical shell 2, thereby realizing elastic wave filtering of the corresponding frequency band.

[0022] The homogeneous thin plate structure 1 is a thin plate of uniform material, with a thickness of h=2 mm, a stiffness of D, and a material of 7075 aluminum alloy.

[0023] The Young's modulus E of the metal material parameter of the homogeneous thin plate structure 1 and the hollow cylindrical shell 2 is 71.7 GPa, and the density of the hollow cylindrical shell and the thin plate elastic wave filter is kg / m 3 , Poisson's ratio is 0.3.

[0024] In this embodiment, the filter frequency f of the elastic wave constructed according to the target requirement is 5400 Hz, and the mode is quadrupole.

[0025] In this embodiment, the radius R is the radius of the ring formed by the hollow cylindrical shell of the elastic wave filter control area, R=58mm, and the wall thickness of the hollow cylindrical shell is 2R t =6mm.

[0026] like Figure 3 As shown, the H obtained by the discrete oscillator construction method is p By scanning the height of the annular cylindrical shell in the finite element model, the quality factor of the elastic wave filter can be obtained as Ref / (2×Imf)=8405 at the discrete cylindrical shell height of H=378.5mm, which can achieve extremely high elastic energy density localization, where: Ref and Imf are the real and imaginary parts of the frequency, respectively.

[0027] like Figure 4 As shown, using Figure 3 The height parameter of the cylindrical shell at the maximum value of the quality factor is H = 378.5 mm, as shown in Figure 3 The vertical dashed line in the middle shows the out-of-plane displacement field of its eigenmode verified in the numerical model. As can be seen in the figure, the filtering frequency in this embodiment is f = 5420 Hz, with an error of less than 0.37% from the target frequency.

[0028] This embodiment is based on the elastic wave filtering application of the elastic wave filter mentioned above, specifically: in aerospace or bridge monitoring, thin plate structures (such as aircraft skins or bridge decks) are susceptible to environmental vibration interference, and it is necessary to accurately extract damage signals in specific frequency bands. This filter can be integrated on the surface of the thin plate, and by selectively filtering non-target frequency band noise, the signal-to-noise ratio of damage identification is improved. The hollow cylindrical shell 2 is constructed according to the structural parameters (R=58mm, H=378.5mm, wall thickness 2R t =6mm) is fixed to the center of the monitoring area of ​​the homogeneous thin plate 1. A double sine signal input of sin(2ptf)+sin(2pt(f+100)) is applied to the bare plate and hollow cylindrical shell thin plate elastic wave filter structure, and the vibration response spectrum before and after filtering is recorded ( Figure 5 ). Compare the spectrum before and after filtering, and extract the amplitude attenuation characteristics of the target frequency band (5400Hz±100Hz). At the target frequency band of 5520Hz, the suppression rate is still maintained at 90.6% (the bare board response amplitude is normalized to 1, and after filtering it is reduced to 0.084). Figure 3 The optimized structure with H=378.5mm has a quality factor Q=8405, which is significantly higher than the existing periodic structure filter.

[0029] The present invention uses a non-periodic hollow cylindrical shell to construct an ultra-high quality factor (Q>8000) and precise frequency band control (error <0.37%), while breaking through the volume and efficiency limitations of existing filters, and showing significant advantages in structural health monitoring, high-sensitivity sensing and communication systems.

[0030] Compared with the existing technology, the present invention achieves broadband elastic wave filtering on a homogeneous thin plate by constructing the resonance characteristics and dimensions of a hollow cylindrical shell and its interaction with a homogeneous thin plate. The present invention uses a discrete oscillator construction method to construct a hollow cylindrical shell elastic wave filter with a specified filtering area, filtering mode, and frequency. The filtering efficiency reaches over 90%, greatly improving the elastic wave filtering efficiency of homogeneous thin plate filter devices. This provides a new approach for high-precision elastic wave filtering of compact thin plate devices and has important engineering application value.

[0031] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principles and purpose of the present invention. The scope of protection of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. All implementation schemes within its scope shall be subject to the constraints of the present invention.

Claims

1. An elastic wave filter based on an annular cylindrical shell thin plate structure, characterized in that: include: Resonant structures of a homogeneous elastic thin plate and a hollow annular cylindrical shell.

2. The elastic wave filter based on the annular cylindrical shell thin plate structure according to claim 1 is characterized in that: The Young's modulus E of the metal material parameter of the homogeneous thin plate structure and the hollow cylindrical shell is 71.7 GPa; the density of the hollow cylindrical shell and the thin plate elastic wave filter is kg / m 3 , Poisson's ratio is 0.

3.

3. The elastic wave filter based on the annular cylindrical shell thin plate structure according to claim 1 is characterized in that: The homogeneous thin plate is a thin plate of uniform material, has a thickness of h=2 mm, a stiffness of D, and is made of 7075 aluminum alloy.

4. A method for implementing the elastic wave filter according to any one of claims 1 to 3, characterized in that: The wall thickness of the hollow annular cylindrical shell is obtained by reverse engineering using the discrete oscillator construction method, specifically including: 1) The construction method of the discrete oscillator is as follows: , , where: H p is the height of the equivalent oscillator, f is the filtering frequency, E is the elastic modulus of the material, R t is the radius of the equivalent discrete oscillator, that is, the wall thickness of the hollow cylindrical shell is 2R t , is the zero-order Bessel function, N is the number of oscillators after the hollow cylindrical shell is discretized into cylinders, E is the Young's modulus of the metal material parameter, is the density of the hollow cylindrical shell thin plate elastic wave filter, D is the bending stiffness of the homogeneous thin plate structure, and h is the thickness of the homogeneous thin plate structure; 2) According to the limiting conditions of the elastic wave filter frequency, the fixed modal control parameter φ, the elastic wave filter frequency f, the material and geometric parameters are determined and the corresponding equivalent vibrator height H is obtained. p , specifically: ,in: is the φ-order Bessel function, k0 is the wave number, and R is the radius of the hollow cylindrical shell; 3) According to the enhancement of the equivalent stiffness due to the coupling effect between discrete elements after the discrete model evolves to the hollow cylindrical shell, the equivalent oscillator height H is modified. p In order to keep the equivalent resonant frequency unchanged, the equivalent oscillator height H around the column p By sweeping the parameters, elastic wave bound states with real eigenfrequencies and high energy density are obtained to construct an optimized elastic wave filter.

5. The method according to claim 4, wherein: The reverse construction is verified by applying the numerical simulation method, that is, the corresponding elastic wave filter entity model is established in the numerical simulation software to verify the arrangement radius R of the resonant cylinder ring under the specified control requirements and the modal control parameters f sim The errors of f and f are within an acceptable range, and dual-frequency incident waves are applied to the elastic wave filter in the time domain module to compare the filtering efficiency and filtering frequency of the bare plate and hollow cylindrical shell thin plate elastic wave filters.

6. Use of the elastic wave filter according to any one of claims 1 to 5, characterized in that: It is used for thin plate vibration characteristic identification, elastic wave filtering and sensing.

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