CN106678271A - Local resonance low-frequency band gap vibration suppression periodic structure - Google Patents

Abstract

The invention relates to a periodic structure with low-frequency vibration suppression performance based on local resonance bandgap characteristics, and belongs to the technical field of aviation, aerospace and ship vibration and noise control. It includes periodically distributed mass elements, elastic elements and matrix. The periodic unit includes a metal structure, that is, a mass element. The side of the mass element is surrounded by a ring of rubber or silicone material, that is, an elastic element. The circumferential side of the mass element is a curved surface with a certain shape, and the elastic element and the mass element are attached to each other. , and then arrange the elastic elements surrounding the mass elements as a whole periodically in the elastic structural matrix, wherein the elastic elements and the matrix are also bonded to each other. The periodic structure of the invention has obvious bandgap characteristics, and the periodic structure based on the local resonance bandgap characteristics has good low-frequency vibration suppression performance.

Description

A Periodic Structure with Local Resonance and Low Frequency Bandgap for Vibration Suppression

technical field

The invention belongs to the technical field of aviation, aerospace and ship vibration and noise control. The invention relates to a periodic structure based on the bandgap characteristic of local resonance and having low-frequency vibration suppression performance.

Background technique

Mechanical noise is the main component of radiated noise in low-speed navigation such as aviation, spaceflight and ships. Especially for low frequency noise, compared with medium and high frequency noise, it has the characteristics of longer propagation distance and stable line spectrum characteristics, which is not conducive to the concealment and safety of aircraft. However, traditional vibration isolation and noise reduction technologies are mostly aimed at the control of medium and high frequency vibration and sound radiation, and the problem of low frequency vibration and noise cannot be effectively solved at present.

Mechanical noise is mainly caused by mechanical vibration, and the noise reduction effect can be achieved through vibration suppression treatment. Since the elastic wave has a bandgap characteristic when propagating in the periodic structure, that is, the propagation of the elastic wave is prohibited within the frequency range of the bandgap, the use of the periodic structure to suppress the system vibration is expected to become a new method of vibration and noise reduction. With the change of the material composition and geometric size of the periodic structure, the frequency range of the band gap and the attenuation characteristics in the band gap of the periodic structure will also change. Therefore, according to this characteristic of the periodic structure, by changing the form of the periodic structure or its internal material component parameters, such as material elastic constants, density, and damping, vibration-suppressing periodic structures with different band gap characteristics can be obtained.

According to the ratio of the wavelength to the lattice constant and the corresponding relationship between the bandgap frequency, the bandgap can be divided into Bragg scattering type (the wavelength corresponding to the bandgap frequency is in the same order as the lattice constant) and local resonance type (the bandgap frequency The corresponding wavelength can be much larger than the lattice constant). The Bragg scattering periodic structure is difficult to obtain a low-frequency bandgap under the condition of a small period size, so it is difficult to be applied in low-frequency vibration and noise reduction; while the bandgap frequency of the local resonance periodic structure is different from that of the oscillator element in the periodic cell. The vibration characteristics are closely related, and the bandgap frequency can be designed to a lower frequency to solve the problem of low-frequency vibration suppression.

Contents of the invention

The object of the present invention is to provide a local resonant low-frequency bandgap vibration-suppressing periodic structure, which can reduce vibration and noise by installing the vibration-suppressing periodic structure on the elastic structure.

To achieve the above object, the present invention adopts the following technical solutions:

A local resonant low-frequency bandgap vibration-suppressing periodic structure includes periodically distributed quality elements, elastic elements and a matrix. The periodic cell includes a metal structure, that is, a mass element. The side of the mass element is surrounded by a ring of rubber or silicone material, that is, an elastic element. The circumferential side of the mass element is a curved surface with a certain shape, and the elastic element and the mass element are attached to each other. Then, the elastic elements surrounding the mass elements are arranged periodically in the elastic structural matrix as a whole, and the elastic elements and the matrix are also attached to each other.

In the local resonance low-frequency bandgap vibration-suppressing periodic structure, the cross-section of the mass element and the shape of the base opening can be circular, triangular, quadrangular, hexagonal, etc., or irregular.

The local resonance low-frequency bandgap vibration-suppressing periodic structure can be distributed in various forms such as rectangle, rhombus or triangle arrangement.

The local resonant low-frequency bandgap suppresses the periodic structure, and the upper and lower surfaces of the elastic substrate on which the periodic structure is laid can be coated with high-damping materials or sound-absorbing materials.

Compared with the classic elastic structure, the vibration suppression periodic structure of the present invention has the following main features:

1. There is a bandgap characteristic in the propagation of elastic waves in periodic structures. In the bandgap frequency range, the propagation of bending waves in the periodic structure is effectively suppressed;

2. The local resonance band gap of the periodic structure mainly comes from the interaction between the resonance characteristics of the periodic cells and the propagation characteristics of the bending wave, and the resonance characteristics of the periodic cells are generated by the shearing action between the elastic element and the mass element;

3. Reasonable selection of structural parameters and material parameters of elastic elements and mass elements, such as elastic elements with small elastic modulus or mass elements with high metal density, can expand the bandgap frequency to low frequencies, thereby achieving lower frequency vibration reduction Purpose;

4. Improving the damping of the elastic element can enhance the energy consumption of the shearing action between the elastic element and the mass element, and the shape design of the circumferential side of the mass element is also conducive to increasing the contact area between it and the elastic element. The damping effect in the large shear process further enhances the broadband vibration suppression performance of the structure, thereby reducing the radiation noise of the structure.

Description of drawings

Figure 1: Schematic diagram of a periodic cell-filled structure.

Figure 2: Schematic cross-section of a periodic cell-filled structure.

Figure 3: Schematic diagram of the vibration suppression period structure of the present invention.

Figure 4: Comparison of the vibration response of the excitation region and the vibration pickup region of the vibration-suppressed periodic structure matrix.

Figure 5: Comparison of the vibration response of the vibration-suppressed periodic structure and the comparison structure in the vibration pickup area.

In the figure: 1—mass element; 2—elastic element; 3—matrix.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the periodic cell includes a metal structure, that is, a mass element 1. The side of the mass element 1 is surrounded by a ring structure of rubber or silicone material, that is, an elastic element 2. The circumferential side of the mass element 1 is a curved surface with a certain shape. And the elastic element 2 and the mass element 1 are attached to each other, as shown in Figure 2; then the basic cells are periodically arranged in the elastic structure matrix 3, wherein the elastic element 2 and the matrix 3 are also attached to each other, and finally The obtained vibration suppression period structure is shown in Fig. 3.

Due to the local resonant bandgap nature of the periodic structure, the propagation of bending waves is suppressed. The vibration suppression effect is mainly reflected in two aspects. One is that the vibration at one end of the substrate of the suppressed periodic structure (the area where the matrix has no periodic cell distribution, called the matrix excitation area) is transmitted to the other end of the matrix through the periodic structure (the other end of the matrix has no periodicity). The region where the cells are distributed, called the matrix pickup region) is suppressed, and the second is that the average vibration response of the vibration-suppressed periodic structure pickup region is reduced compared with the classical elastic structure (comparative structure). In this specific embodiment, the size of the vibration suppression periodic structure matrix is 1000mm×455mm×4mm, the material is steel, the number of round holes arranged periodically in the middle is 8×7, the hole diameter is 50mm, and the hole spacing is 65mm; the diameter of the mass element is 30mm, and the material is Lead; the elastic element is a rubber material with a modulus of 10 ⁷ Pa and a loss factor of 0.2. The normal excitation is applied at one end of the matrix, and the comparison curves of the average vibration response of the excitation area and the vibration pickup area of the periodic structure matrix, and the comparison of the vibration response of the vibration pickup area of the periodic structure and the comparison structure are given, as shown in Fig. 4 and Fig. 5, respectively. It can be seen from the figure that the periodic structure has obvious bandgap characteristics, and the periodic structure based on the local resonance bandgap characteristics has good low-frequency vibration suppression performance.

Claims (4)

1. A local resonance low-frequency bandgap vibration suppression periodic structure, comprising a periodically distributed quality element 1, an elastic element 2 and a matrix 3, is characterized in that: the periodic unit includes a metal structure, namely a quality element 1, and the quality element 1 side surrounds a The ring structure of rubber or silicone material is the elastic element 2. The circumferential side of the mass element 1 is a curved surface with a certain shape, and the elastic element 2 and the mass element 1 are attached to each other, and then the elastic element 2 surrounds the mass element 1 Arranged periodically in the elastic structural matrix 3 as a whole, wherein the elastic elements 2 and the matrix 3 are also bonded to each other. 2. The local resonance low-frequency bandgap vibration-suppressing periodic structure according to claim 1, characterized in that: the mass element 1 cross-section and the matrix 3 opening shapes can be circular, triangular, quadrangular, hexagonal, etc., and can also be is irregular in shape. 3. The local resonance low-frequency bandgap vibration suppression periodic structure according to claim 1 or 2, characterized in that: the periodic distribution form can be rectangular, rhombus or triangular arrangement, etc. 4. The local resonance low-frequency bandgap vibration-suppressing periodic structure according to claim 1, 2 or 3, characterized in that the upper and lower surfaces of the elastic matrix 3 on which the periodic structure is laid can be coated with high damping materials or sound-absorbing materials.