Damping and bearing integrated dot matrix metamaterial

Abstract

The invention belongs to the technical field of vibration reduction and bearing, and particularly relates to a vibration reduction and bearing integrated dot matrix metamaterial. The dot matrix metamaterial is formed by periodically arraying a plurality of unit cells in a space; each unit cell comprises a center supporting truss framework and a local resonance function panel, the center supporting truss framework comprises a cubic frame and an inner core supporting rod system arranged in the cubic frame to form a high-rigidity bearing body, and the local resonance function panels are arranged on the top face and / or the bottom face of the cubic frame. The multi-modal local resonance system is constructed by a multi-stage nested hollow groove system, and multi-modal local resonance is utilized to introduce a plurality of band gaps in a low-frequency band so as to realize effective suppression of low-broadband vibration. According to the dot matrix metamaterial, the decoupling design of the static bearing performance and the dynamic vibration reduction performance is achieved, the vibration reduction performance requirement under multiple frequency bands can be met, and the dot matrix metamaterial has the wide engineering application range.

Description

Technical Field

[0001] This invention belongs to the technical field of vibration reduction and load bearing, specifically relating to a lattice metamaterial that integrates vibration reduction and load bearing. Background Technology

[0002] With the continuous development of my country's aviation technology, aviation equipment, represented by the new generation of large aircraft, has placed higher demands on vibration levels and load-bearing capacity. Ensuring load-bearing capacity and effectively suppressing vibration levels while meeting lightweight structural design requirements is essential for ensuring the normal performance of such equipment and is also key to improving its safety and reliability. Existing methods using additional damping materials have limited effectiveness in suppressing low-frequency vibrations and also face the problem of material aging. While dynamic vibration absorbers are suitable for lower-frequency vibrations, their effective bandwidth is narrow. Therefore, it is urgent to explore new technologies to overcome the limitations of these existing methods.

[0003] Lattice sandwich panels, consisting of a face panel and a periodic lattice core layer, possess advantages such as lightweight, high specific strength, and high specific stiffness, making them widely used in static load-bearing and impact resistance applications. However, due to their high porosity, existing lattice sandwich panels exhibit low structural damping, making it difficult to effectively suppress vibration transmission. The emergence of mechanical metamaterials offers a new approach to solving these problems. By designing specific microstructural units (unit cells), mechanical metamaterials can generate elastic wave bandgap based on Bragg scattering or local resonance mechanisms, blocking vibration propagation within specific frequency bands. Currently, although there are studies introducing metamaterial bandgap mechanisms into lattice sandwich panels, aiming to construct structures that balance load-bearing and vibration reduction, existing designs often struggle to achieve efficient low-frequency, broadband vibration reduction while maintaining lightweight and high load-bearing capacity. Therefore, developing a vibration-damping and load-bearing integrated lattice sandwich metamaterial that can balance lightweight, high strength, and low-frequency broadband vibration reduction performance has significant engineering application value. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a lattice metamaterial that integrates vibration reduction and load bearing. This material integrates a resonant panel with multi-level nested hollow features on the surface of an existing centrally supported cubic lattice structure. By utilizing a hollowed-out groove system to construct a multimodal local resonance system, multiple band gaps are introduced in the low-frequency band without disrupting the load bearing path of the lattice structure, thereby achieving effective attenuation of vibrations at specific frequencies.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A lattice metamaterial integrating vibration reduction and load bearing is composed of a number of unit cells periodically arrayed in space. Each unit cell includes a central supporting truss skeleton and a local resonant functional panel. The central supporting truss skeleton includes a cubic frame and an inner core support rod system disposed inside the cubic frame. The inner core support rod system connects the corner points of the cubic frame to the central region of the unit cell, forming a high-rigidity load-bearing body. The local resonant functional panel is disposed on the top surface and / or bottom surface of the cubic frame. The local resonant functional panel has a perforated groove system that penetrates the thickness direction. The perforated groove system divides the local resonant functional panel into a panel outer frame fixed to the cubic frame and a multi-level resonant subsystem suspended inside the panel outer frame. The multi-level resonant subsystem includes at least two levels of mass blocks and elastic connectors connecting the mass blocks, forming a multi-degree-of-freedom mass-spring system.

[0006] In some possible implementations, the inner core support system consists of two centrally symmetrical pyramidal truss structures; each pyramidal truss structure comprises four diagonal members, the bottom ends of which are respectively connected to the four corner points of the same surface of the cube frame, and the top ends of which converge toward the geometric center of the unit cell.

[0007] In some possible implementations, the multi-stage resonant subsystem is nested and includes: a primary suspension frame disposed inside the outer frame of the panel, primarily serving as the oscillator mass; a primary elastic connector connecting the outer frame of the panel and the primary suspension frame, providing a first spring stiffness; a secondary central mass block disposed in a cavity inside the primary suspension frame; and a secondary elastic connector connecting the primary suspension frame and the secondary central mass block, providing a second spring stiffness.

[0008] In some possible implementations, the primary elastic connector is an orthogonal connecting beam distributed in the middle of each side of the panel outer frame, mainly providing torsional stiffness; the secondary elastic connector is a diagonal connecting beam extending along the diagonal direction, connecting the inner corner of the primary suspension frame with the secondary center mass block, mainly providing bending stiffness; through the geometric heterogeneous design of the orthogonal connecting beam and the diagonal connecting beam, multimodal resonance is stimulated.

[0009] In some possible implementations, the secondary central mass block consists of a central rectangular block and four trapezoidal blocks extending outwards from the rectangular block, with the diagonal connecting beams extending into the gaps between the trapezoidal blocks to increase resonant mass and optimize space utilization.

[0010] In some possible implementations, the unit cell forms a periodic array along a single direction, and the number of array elements is not less than 4, constituting a one-dimensional lattice metamaterial beam; or, the unit cell forms a periodic array along two orthogonal directions, and the number of array elements in at least one direction is not less than 4, constituting a two-dimensional lattice metamaterial plate.

[0011] In some possible implementations, the cubic frame consists of four vertical columns and edge frames on the top and bottom surfaces, and the columns and diagonal braces of the central supporting truss skeleton have a cross-sectional shape of one of the following: circular, rectangular, polygonal, or hollow tubular.

[0012] One of the above technical solutions has the following beneficial effects: This invention introduces the local resonance mechanism of acoustic metamaterials into structural engineering lattices. The central support truss bears the main static load, ensuring high specific strength and high specific stiffness of the structure; the local resonance functional panels provide dynamic adjustment, achieving vibration reduction through the vibration energy dissipation of a multi-level resonant subsystem. The two components are spatially independent, achieving a perfect functional integration. Unlike existing designs with a single resonant frequency, this invention, through a multi-level stiffness system composed of orthogonal and diagonal connecting beams, combined with a multi-level mass system composed of a primary suspension frame and a secondary central mass block, can excite a rich variety of local resonant modes. This allows the structure to open multiple band gaps or form a wider attenuation band in the low-frequency range, effectively solving the problem of low-frequency vibration isolation difficulties in existing lightweight structures. The resonant frequency of the structure mainly depends on the geometric parameters of the panel's perforated groove system, while the load-bearing capacity mainly depends on the diameter of the frame members. This design allows engineers to independently adjust the vibration reduction frequency band and load-bearing capacity, greatly improving design flexibility and enabling a wide range of engineering applications. Attached Figure Description

[0013] The features, advantages and technical effects of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic diagram of the three-dimensional structure of a lattice metamaterial unit cell of the present invention.

[0015] Figure 2 This is a front view schematic diagram of the lattice metamaterial unit cell of the present invention.

[0016] Figure 3 This is a schematic diagram of the three-dimensional structure of the cubic framework in the unit cell of the lattice metamaterial of the present invention.

[0017] Figure 4 This is a three-dimensional structural diagram of the symmetrical pyramid-shaped inner core support rod system in the unit cell of the lattice metamaterial of the present invention.

[0018] Figure 5This is a three-dimensional structural schematic diagram of the localized resonance functional panel in the unit cell of the lattice metamaterial of the present invention.

[0019] Figure 6 This is a top view of the localized resonance functional panel in the unit cell of the lattice metamaterial of the present invention.

[0020] Figure 7 This is a three-dimensional structural diagram of the lattice metamaterial beam of the present invention.

[0021] Figure 8 The diagram shows the vibration transmissibility analysis results of the lattice metamaterial beam of the present invention.

[0022] Figure 9 This is a three-dimensional structural diagram of the lattice metamaterial plate of the present invention.

[0023] Figure 10 The diagram shows the vibration transmissibility analysis results of the lattice metamaterial plate of the present invention.

[0024] Figure 11 This is a vibration distribution diagram of the lattice metamaterial beam of the present invention at 355Hz.

[0025] Figure 12 This is a vibration distribution diagram of the lattice metamaterial plate of the present invention at 700 Hz.

[0026] The reference numerals in the attached figures are explained as follows: 1-Cube frame; 2-Inner core support rod system; 3-Panel frame; 4-Level 1 Suspension Frame; 5- Primary elastic connector; 6- Secondary elastic connector; 7-Secondary center mass block. Detailed Implementation

[0027] The specification and claims use certain terms to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." The term "connection" can mean a direct connection between components or an indirect connection between components through other parts.

[0028] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be interpreted as indicating or implying relative importance.

[0029] The present invention will be further described in detail below with reference to the accompanying drawings, but this is not intended to limit the scope of the invention.

[0030] join Figure 1-6 This embodiment provides a unit cell of a vibration-damping and load-bearing integrated lattice metamaterial, mainly assembled or integrally formed from two parts: a central support truss skeleton and a localized resonant functional panel. The unit cell skeleton includes a cubic frame 1, consisting of four vertical columns and edge frames on the upper and lower bottom surfaces. Inside the frame, there is an inner core support rod system 2. In this embodiment, the inner core support rod system 2 is designed as a double pyramid truss structure, containing eight diagonal members. The bottom ends of these eight diagonal members are respectively connected to the four corner points of the upper and lower bottom surfaces of the cubic frame, and the top ends converge towards the geometric center of the unit cell and are fixed. The central support truss skeleton can be mainly made of high-modulus materials (such as titanium alloy, aluminum alloy, or engineering plastics), or it can be integrally printed using 3D printing materials such as resin, forming the main load-bearing path of the unit cell and ensuring that the structure has high specific stiffness and specific strength under static load.

[0031] The top and bottom surfaces of the unit cell are covered with a localized resonant functional panel. This localized resonant functional panel is fabricated using processes such as laser cutting, waterjet cutting, or high-precision 3D printing to create a series of perforated grooves running through the thickness of the sheet material, thus forming multi-level nested resonant units. The specific structure includes: a panel outer frame 3: the outermost solid part of the panel, fixed to the edge frame of the skeleton, serving as the boundary for vibration transmission; a primary suspension frame 4: a square annular mass block located inside the panel outer frame 3, connected to the panel outer frame 3 via orthogonal connecting beams distributed at the midpoints of its four sides. The orthogonal connecting beams are relatively short, serving as primary elastic connectors 5; a secondary central mass block 7: a solid mass block located at the center of the panel, designed in this embodiment as a combination of a "central square block + surrounding trapezoidal blocks" to maximize mass utilization; and diagonal connecting beams: a set of slender beams extending along the diagonal direction, one end of which connects to the inner corner of the primary suspension frame 4, and the other end extends into and connects to the gap of the secondary central mass block 7. The diagonal connecting beam, as a secondary elastic connector 6, has a significantly different length and slenderness ratio compared to the orthogonal connecting beam.

[0032] The orthogonal connecting beam and the primary suspension frame 4 constitute the first-stage oscillator, while the diagonal connecting beam, the primary suspension frame 4, and the secondary central mass block 7 constitute the second and third-stage oscillators. When elastic waves are transmitted through the outer frame 3 of the panel, due to the different natural frequencies of the multi-stage oscillators and their mutual coupling, the system will generate multimodal local resonance in a specific low-frequency range, converting vibration energy into the kinetic energy of the oscillators, thereby suppressing the transmission of vibration and achieving the purpose of vibration reduction in a low-frequency wideband range.

[0033] The following examples illustrate the double-sided elastic metasurface of the present invention: A lattice metamaterial was fabricated using 3D printing technology. The selected material was a photosensitive resin with a density of [missing information]. The Young's modulus is 1.98 GPa, and Poisson's ratio is 0.37. In the aforementioned unit cell, the cube frame 1 has a side length of 50 mm, and the four vertical columns and the edge frames of the top and bottom surfaces are all square with a side length of 3 mm. The radius of the pyramid's inner core support system 2 is 2 mm. The thickness of the localized resonant functional panel is 2 mm, and the width of the panel's outer frame 3 is 3 mm, consistent with the dimensions of the cube frame 1's border. The length and width of the orthogonal connecting beams are 5 mm and 1 mm respectively; the length and width of the diagonal connecting beams are 15 mm and 1 mm respectively; the side length of the central cube in the secondary central mass block 7 is 5 mm; the width of the slot parallel to the orthogonal connecting beams is 1.5 mm, the width of the slot parallel to the diagonal connecting beams is 1.5 mm, and the width of the remaining slots is 1 mm. Based on the above data, an example of a lattice metamaterial unit cell can be obtained.

[0034] See Figure 7 By periodically arranging the aforementioned unit cells along a single direction (x-axis), this embodiment constructs a lattice metamaterial beam containing 6 unit cells. To verify its vibration reduction effect, vibration transmission characteristics were simulated and tested on the metamaterial beam. The simulation conditions were: a frequency sweep excitation along the vertical (z-axis) direction was applied to one end boundary of the beam, and the displacement response signal was picked up at the other end of the beam. The vibration transmissibility was calculated and compared with an existing lattice structure covered with a slotted panel. Figure 8 The vibration transmissibility curve of the metamaterial beam is shown. In multiple frequency bands [341,388] Hz, [467,485] Hz, and [606,865] Hz, the vibration transmissibility of the lattice metamaterial beam is less than 0 dB, exhibiting significant attenuation troughs, i.e., band gaps. Within these frequency bands, the lowest vibration transmissibility is as low as -88.4 dB, indicating that vibration is significantly suppressed. Furthermore, in multiple broadband frequency ranges of [280,394] Hz, [464,507] Hz, and [572,819] Hz, the vibration transmissibility of the lattice metamaterial beam is lower than that of existing lattice structures, indicating that the lattice metamaterial beam has superior vibration suppression compared to existing structures. Modal analysis reveals that these vibration suppression frequency bands correspond to the translational and torsional resonances of the primary suspension frame 4 and the translational resonance of the secondary central mass block 7 in the panel. The results demonstrate that the metamaterial beam in this embodiment achieves efficient vibration reduction for a specific low-frequency band while maintaining the load-bearing capacity of the lattice structure.

[0035] join Figure 9By periodically arranging the aforementioned unit cells along two orthogonal directions (x-axis and y-axis), this embodiment constructs a 4×6 lattice metamaterial plate. Vibration transmission characteristics of this metamaterial plate are analyzed and compared with existing lattice structures covering uniformly oriented panels. Excitation points are located at one edge of the plate, and response points are located at the opposite edge. Figure 10 The figure shows the vibration transmissivity curve of the metamaterial plate. The curve shows that in the wide frequency range of [257,388] Hz, [438,484] Hz, [492,528] Hz and [594,814] Hz, the vibration transmissivity of the lattice metamaterial plate is lower than that of the existing lattice structure, indicating that the lattice metamaterial of this embodiment has a better vibration suppression effect.

[0036] Figure 11 The image shows the vibration distribution of an existing beam (left) and a lattice metamaterial beam (right) at 355 Hz. Figure 12 The image shows the vibration distribution of an existing beam (left) and a lattice metamaterial plate (right) at 700 Hz. It can be seen that, unlike the existing beam and plate where the vibration energy is distributed throughout the entire structure, the vibration energy of the lattice metamaterial beam and plate is mainly concentrated inside the local resonant panels of each unit cell, i.e., components 4 and 7 vibrate. The vibration amplitude of the columns and diagonal rods that serve as the skeleton is extremely small, which verifies the effectiveness of the multimodal local resonant panels in broadband vibration suppression.

[0037] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments described above, and any obvious improvements, substitutions, or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A lattice metamaterial integrating vibration reduction and load bearing, characterized in that: It is composed of a number of unit cells arranged periodically in space; the unit cell includes a central support truss skeleton and a local resonant functional panel. The central support truss skeleton includes a cubic frame (1) and an inner core support rod system (2) disposed inside the cubic frame (1). The inner core support rod system (2) connects the corners of the cubic frame (1) with the central area of ​​the unit cell to form a load-bearing body. The local resonant functional panel is disposed on the top surface and / or bottom surface of the cubic frame (1). The local resonant functional panel is provided with a hollow groove system. The hollow groove system divides the local resonant functional panel into a panel outer frame (3) fixed to the cubic frame (1) and a multi-level resonant subsystem suspended inside the panel outer frame (3). The multi-level resonant subsystem includes at least two levels of mass blocks and elastic connectors connecting the mass blocks.

2. The lattice metamaterial for integrated vibration reduction and load bearing as described in claim 1, characterized in that: The inner core support system (2) consists of two centrally symmetrical pyramid truss structures; each pyramid truss structure contains four diagonal rods, the bottom ends of which are respectively connected to the four corner points of the same surface of the cube frame (1), and the top ends of which converge toward the geometric center of the unit cell.

3. The lattice metamaterial for integrated vibration reduction and load bearing as described in claim 2, characterized in that: The multi-level resonant subsystems are nested in a nested manner, and the multi-level resonant subsystems include: A primary suspension frame (4) is disposed inside the outer frame (3) of the panel; A primary elastic connector (5) connects the panel outer frame (3) to the primary suspension frame (4); The secondary center mass block (7) is disposed in the cavity inside the primary suspension frame (4); The secondary elastic connector (6) connects the primary suspension frame (4) and the secondary center mass block (7).

4. The lattice metamaterial integrating vibration reduction and load bearing as described in claim 3, characterized in that: The primary elastic connector (5) is an orthogonal connecting beam distributed in the middle of each side of the outer frame of the panel (3); the secondary elastic connector (6) is a diagonal connecting beam connecting the inner corner of the primary suspension frame (4) to the secondary center mass block (7).

5. The lattice metamaterial for integrated vibration reduction and load bearing as described in claim 4, characterized in that: The secondary center mass block (7) consists of a central rectangular block and four trapezoidal blocks extending outwards from the rectangular block. The diagonal connecting beam extends into the gap between the trapezoidal blocks.

6. The lattice metamaterial for integrated vibration reduction and load bearing as described in claim 5, characterized in that: The unit cells form a periodic array along a single direction, and the number of array units is not less than 4, constituting a one-dimensional lattice metamaterial beam; or, the unit cells form a periodic array along two orthogonal directions, and the number of array units is not less than 4, constituting a two-dimensional lattice metamaterial plate.

7. The lattice metamaterial integrating vibration reduction and load bearing as described in claim 6, characterized in that: The cube frame (1) consists of four vertical columns and edge frames on the top and bottom surfaces. The columns and the diagonal rods have a cross-sectional shape that is circular, rectangular, polygonal, or hollow tubular.

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