Metamaterial pipeline vibration absorber structure with adjustable band gap

Abstract

The invention relates to the technical field of pipeline vibration control, and discloses a band-gap-adjustable metamaterial pipeline vibration absorber structure which comprises a main vibrator module used for being installed on the outer wall of a metamaterial pipeline base body, generating a local resonance band gap based on the metamaterial local resonance effect, restraining transmission of elastic waves in a pipeline and achieving effective control over low-frequency vibration; the additional vibrator module is adjustably arranged on the main vibrator module along the axial direction of the metamaterial pipeline base body in a sliding manner so as to realize the adjustability and accurate control of the vibration suppression frequency band of the metamaterial pipeline; the low-frequency vibration suppression of the metamaterial pipeline is realized through the synergistic effect of the main vibrator module and the additional vibrator module. The resonance frequency of the additional vibrator is adjusted through mechanical sliding, the band gap range is dynamically widened, and the contradiction between the fixed frequency band of a traditional vibration absorber and complex and changeable pipeline vibration is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline vibration control, and in particular, to a metamaterial pipeline vibration absorber structure with adjustable bandgap. Background Art

[0002] Pipelines are used to carry the propagation of fluids to transfer energy, momentum, and mass, and are widely used in fields such as industry, ships, military, aerospace, ocean, and nuclear industry. The equipment pipeline system has characteristics such as many mechanical devices, complex excitations, and dense layouts, and is prone to complex and variable vibrations. On the one hand, the propagation of pipeline vibrations will induce strong vibrations and noises, seriously affecting the safety and concealment of the equipment. On the other hand, it will damage the pipeline system and various precision instruments and meters, and will also cause structural fatigue, resulting in structural failures, reducing the equipment life, affecting its normal operation, and may even cause pipeline bursts in severe cases, resulting in the failure of the pipeline system and then causing disaster accidents. Therefore, the vibration control problem of pipelines in equipment is an urgent problem to be solved in the current vibration reduction field.

[0003] The main source of pipeline vibration is the mechanical vibration generated during the operation of pump machines. Its vibration energy is mainly concentrated in low-frequency bands such as pump shaft frequency and blade frequency, especially the low-frequency line spectrum below 200 Hz is obvious. Due to the differences in the pipeline structures and working conditions of different equipment, there are large differences in the vibration line spectra of pipelines. Traditional pipeline vibration reduction measures are difficult to achieve unified and effective vibration control for the complex vibrations of different pipelines. The complex vibration problems of pipelines pose a severe test to the existing vibration control technologies, and there is an urgent need to develop new vibration absorber structure designs that can effectively suppress the pipeline vibrations under different pipeline structures and different working conditions, in order to effectively suppress the complex vibrations of equipment pipelines.

[0004] Currently, traditional pipeline vibration control methods mainly include: mass tuning damper technology, fluid vibration dampers, damping vibration reduction structures, elastic support vibration isolation structures, flexible pipeline structures, and so on. Traditional methods can achieve the suppression of high-frequency vibrations of pipelines, but they cannot effectively suppress the low-frequency vibrations of structures and complex and variable vibration line spectra. Traditional vibration reduction technologies have significant technical bottlenecks: First, limited by the mass law, they can only generate a single vibration reduction band, and the bandwidth is generally only dozens of Hz, and the vibration control frequency band is relatively narrow, unable to achieve full-coverage wide-frequency vibration suppression. Second, the pipeline vibration reduction structure is relatively fixed, resulting in its vibration reduction frequency band being generally fixed and unchanged, unable to change the structure according to the changes in the working conditions of the pipeline system and the changes in the pipeline vibration line spectra, and it is difficult to effectively suppress the complex vibrations of pipelines. Third, traditional metamaterial vibration absorbers generally need to be connected in parallel with multiple units for multi-band vibration absorption, significantly increasing the volume, and it is difficult to deploy in equipment pipeline systems with limited space. Summary of the Invention

[0005] The present invention provides a structure of a metamaterial pipeline vibration absorber with adjustable bandgap to solve the technical problem that the existing traditional pipeline vibration control methods cannot effectively suppress the low-frequency vibration and complex and variable vibration line spectra of the structure.

[0006] The present invention provides a structure of a metamaterial pipeline vibration absorber with adjustable bandgap, including: a main oscillator module, which is used to be installed on the outer wall of the metamaterial pipeline matrix, generate a local resonance bandgap based on the local resonance effect of the metamaterial, suppress the transmission of elastic waves in the pipeline, and achieve effective control of low-frequency vibration; an additional oscillator module, which is arranged on the main oscillator module in an axially slidable and adjustable manner along the metamaterial pipeline matrix to achieve adjustable and precise control of the vibration suppression frequency band of the metamaterial pipeline; and the low-frequency vibration suppression of the metamaterial pipeline is achieved through the synergistic effect of the main oscillator module and the additional oscillator module.

[0007] Furthermore, the main oscillator module includes an elastic bearing ring and a mass ring. An elastic bearing ring is provided at each end of the mass ring, and both ends of the mass ring are fixed on the outer wall of the metamaterial pipeline matrix through the elastic bearing rings; the inner wall surface of the mass ring is attached to the outer wall surface of the elastic bearing ring, and the mass ring is fixedly connected to the elastic bearing ring.

[0008] Furthermore, the mass ring is formed by relatively buckling and connecting two half-ring units.

[0009] Furthermore, the additional oscillator module is arranged on the mass ring via a sliding module; the sliding module includes a slide rail, a connecting clamping ring, and a locking member. The slide rail is arranged on the outer wall surface of the mass ring along the axial direction of the mass ring, and multiple slide rails are arranged at equal intervals along the circumferential direction of the mass ring; the connecting clamping ring is arranged around the mass ring along the circumferential direction and is fixedly connected to the additional oscillator module, and the connecting clamping ring and the additional oscillator module are jointly and slidably connected with the slide rail. The locking member is arranged along the radial direction of the mass ring, and by rotating the locking member, the connecting clamping ring and / or the additional oscillator module are locked on the mass ring.

[0010] Furthermore, two connecting clamping rings are respectively arranged at both ends of the mass ring and are arranged oppositely, and a synchronous driving mechanism is arranged between the two connecting clamping rings to drive the two connecting clamping rings to slide synchronously and relatively close or slide synchronously and relatively away.

[0011] Furthermore, the synchronous driving mechanism includes a mounting boss, a gear, and a rack; the mounting boss is arranged on the outer wall surface of the mass ring and is located at the central position between the two connecting clamping rings. The gear is rotatably arranged on the mounting boss. A rack arranged along the axial direction is provided on each connecting clamping ring and the rack faces the mounting boss. The racks of the two connecting clamping rings are relatively meshed and connected to the gear and the non-toothed edges of the racks are limited by the mounting boss; by driving the gear to rotate, the axial movement of the rack is driven, and further the two connecting clamping rings are driven to slide synchronously and close or slide synchronously and away.

[0012] Furthermore, the additional oscillator module includes a plurality of cantilever units, which are arranged on the connecting snap ring along the axial direction of the connecting snap ring, and the cantilever ends are arranged towards the side away from the mass ring, and the plurality of cantilever units are arranged at equal intervals along the circumferential direction of the connecting snap ring.

[0013] Furthermore, the cantilever units on the two connecting snap rings are arranged in one-to-one correspondence; or the cantilever units on the two connecting snap rings are arranged relatively offset; or the number of cantilever units on the two connecting snap rings is the same; or the number of cantilever units on the two connecting snap rings is different.

[0014] Furthermore, the cantilever unit includes a cantilever beam and a tip mass, the tip mass is located at the cantilever end of the cantilever beam, and the connecting end of the cantilever beam is slidably connected with the slide rail and fixedly connected with the corresponding connecting snap ring.

[0015] Furthermore, the cantilever beam and / or the tip mass are metal material parts; and / or the mass ring is a metal material part, and the elastic bearing ring is a viscoelastic material part.

[0016] The present invention has the following beneficial effects: 1. The main oscillator module generates a local resonance band gap based on the local resonance effect of metamaterials, which can effectively block the propagation of elastic waves in the pipeline in the low-frequency band, and solves the problem of poor suppression effect of traditional vibration reduction technology on low-frequency vibration.

[0017] 2. Through the precise design of the local resonance band gap, directional attenuation can be achieved for characteristic line spectra such as pump shaft frequency and blade frequency, and the low-frequency vibration energy of the pipeline system can be significantly reduced.

[0018] 3. The design that the additional oscillator module is axially slidable and adjustable along the pipeline enables the band gap range of the vibration absorber to be flexibly adjusted according to actual working conditions. By changing the position or number of the additional oscillator modules, different vibration line spectra can be adapted in real time, overcoming the defect that traditional fixed structures cannot adapt to changing vibration environments.

[0019] 4. The synergistic effect of the main oscillator module and the additional oscillator module can expand the band gap bandwidth and achieve simultaneous suppression of multi-band vibrations. Compared with traditional metamaterial vibration absorbers that need to connect multiple units in parallel, the present invention can cover a wider frequency range through parameter adjustment of a single structure, solving the problem of the contradiction between narrow-band suppression and volume.

[0020] 5. The structure of the metamaterial pipeline vibration absorber with adjustable band gap of the present invention realizes the unity of efficient suppression of low-frequency vibration, adaptation and matching of frequency bands, and structural compactness through adjustable band gap design, solves the technical problem of complex vibration control in the equipment pipeline system, and is especially suitable for application scenarios with strict requirements for concealment and reliability.

[0021] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is a schematic structural diagram of a metamaterial circular tube pipeline vibration absorber with adjustable bandgap according to a preferred embodiment of the present invention; Figure 2 is a schematic cross-sectional structural diagram of a metamaterial circular tube pipeline vibration absorber with adjustable bandgap according to a preferred embodiment of the present invention; Figure 3 is a schematic structural diagram of a main oscillator module of a metamaterial pipeline vibration absorber according to a preferred embodiment of the present invention; Figure 4 is a schematic cross-sectional structural diagram of a main oscillator module of a metamaterial pipeline vibration absorber according to a preferred embodiment of the present invention; Figure 5 is a schematic structural diagram of an additional oscillator module of a metamaterial pipeline vibration absorber according to a preferred embodiment of the present invention; Figure 6 is a schematic structural diagram of the assembly of a connection clamp, a gear and a rack of a metamaterial pipeline vibration absorber according to a preferred embodiment of the present invention; Figure 7 is a schematic structural diagram of a periodic arrangement pipeline of four metamaterial pipeline vibration absorbers according to a preferred embodiment of the present invention; Figure 8 is a band structure diagram of a metamaterial pipeline vibration absorber according to a preferred embodiment of the present invention; Figure 9 is a comparison diagram of simulation results of vibration transmission rate - frequency curves of a pipeline with a metamaterial vibration absorber installed and a pipeline without a metamaterial vibration absorber installed according to a preferred embodiment of the present invention; Figure 10 is a schematic diagram of the change in the protruding length l of a cantilever beam in a metamaterial pipeline vibration absorber according to a preferred embodiment of the present invention; Figure 11 is a vibration transmission rate - frequency curve diagram of a pipeline with a metamaterial pipeline vibration absorber installed under different conditions of the protruding length of the cantilever beam according to a preferred embodiment of the present invention; Figure 12 is a schematic structural diagram of a metamaterial square pipeline vibration absorber with adjustable bandgap according to a preferred embodiment of the present invention; Figure 13 is a schematic structural diagram of a main oscillator module of a metamaterial square pipeline vibration absorber according to a preferred embodiment of the present invention; Figure 14It is a schematic diagram of a periodic arrangement of pipes of four metamaterial square pipe vibration absorbers according to a preferred embodiment of the present invention; Figure 15 It is a comparison diagram of simulation results of vibration transmission rate - frequency curves of a square pipe with a metamaterial vibration absorber and a control square pipe without a metamaterial vibration absorber according to a preferred embodiment of the present invention; Figure 16 It is a schematic structural diagram of a guiding mechanism according to a preferred embodiment of the present invention; Figure 17 It is a schematic structural diagram of a synchronous driving mechanism and a guiding mechanism according to a preferred embodiment of the present invention.

[0023] Legend: 100, metamaterial pipe matrix; 200, elastic bearing ring; 300, mass ring; 400, slide rail; 500, connecting snap ring; 600, locking member; 700, mounting boss; 800, gear; 900, rack; 1000, cantilever beam; 1100, tip mass; 1200, counterbore; 1300, guiding rod; 1400, guide groove table. Detailed implementation manners

[0024] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways defined and covered by the following.

[0025] Such as Figure 1 And Figure 2As shown in the figure, the structure of the metamaterial pipeline vibration absorber with adjustable bandgap in this embodiment includes: a main oscillator module, which is used to be installed on the outer wall of the metamaterial pipeline matrix 100, generate a local resonance bandgap based on the local resonance effect of the metamaterial, suppress the transmission of elastic waves in the pipeline, and achieve effective control of low-frequency vibration; an additional oscillator module, which is arranged on the main oscillator module in an axially slidable and adjustable manner along the metamaterial pipeline matrix 100 to achieve adjustable and precise control of the vibration suppression frequency band of the metamaterial pipeline; the low-frequency vibration suppression of the metamaterial pipeline is achieved through the synergistic effect of the main oscillator module and the additional oscillator module. For the structure of the metamaterial pipeline vibration absorber with adjustable bandgap of the present invention, the main oscillator module generates a local resonance bandgap based on the local resonance effect of the metamaterial, which can effectively block the propagation of elastic waves in the pipeline in the low-frequency band (especially below 200 Hz), solves the problem of poor low-frequency vibration suppression effect of traditional vibration reduction technologies, and through the precise design of the local resonance bandgap, can achieve directional attenuation for characteristic line spectra such as pump shaft frequency and blade frequency, and significantly reduce the low-frequency vibration energy of the pipeline system. The design of the additional oscillator module that is axially slidable and adjustable along the pipeline enables the bandgap range of the vibration absorber to be flexibly adjusted according to actual working conditions. By changing the position or number of the additional oscillator modules, different vibration line spectra can be adapted in real time, overcoming the defect that traditional fixed structures cannot adapt to variable vibration environments. The synergistic effect of the main oscillator module and the additional oscillator module can expand the bandgap bandwidth and achieve simultaneous suppression of multi-band vibrations. Compared with traditional metamaterial vibration absorbers that require multiple units to be connected in parallel, the present invention can cover a wider frequency range through the parameter adjustment of a single structure, solving the problem of the contradiction between narrow-band suppression and volume. The modular design ensures the adjustable bandgap while avoiding the problem of volume expansion caused by traditional multi-unit parallel connection, and is especially suitable for equipment pipeline systems with limited space; the main oscillator module is directly integrated on the outer wall of the pipeline, and the sliding adjustment of the additional oscillator module does not require a complex drive mechanism, which is convenient for actual installation and maintenance. By adjusting the position or combination form of the additional oscillator module, the target frequency band can be accurately matched, avoiding the "over-suppression" or "under-suppression" phenomena caused by fixed bandgaps in traditional methods. In addition, mechanical sliding adjustment is more adaptable to harsh working conditions such as high temperature and high pressure than electronic tuning, improving the environmental robustness of the system. The structure of the metamaterial pipeline vibration absorber with adjustable bandgap of the present invention realizes the unity of efficient suppression of low-frequency vibration, adaptation and matching of frequency bands, and structural compactness through adjustable bandgap design, solves the technical problems of complex vibration control in equipment pipeline systems, and is especially suitable for application scenarios with strict requirements for concealment and reliability.

[0026] The metamaterial pipeline is a special pipeline structure designed based on metamaterials technology. Through artificially designed micro or macro structures, it can achieve physical properties (such as acoustic, thermal, mechanical or electromagnetic characteristics) that cannot be achieved by traditional materials. The metamaterial pipeline regulates the propagation characteristics of elastic waves through artificially designed periodic structures, and can form a bandgap in a specific frequency range to block vibration transmission. Combining with the structure of the metamaterial pipeline vibration absorber with adjustable bandgap of the present invention, it realizes precise adjustment of the bandgap and low-frequency adaptability, and further meets the requirements of the equipment pipeline system for wide-frequency adjustable and compact low-frequency vibration absorption.

[0027] Such as Figure 2 And Figure 4As shown, in this embodiment, the main oscillator module includes an elastic bearing ring 200 and a mass ring 300. An elastic bearing ring 200 is provided at each end of the mass ring 300. Both ends of the mass ring 300 are fixed to the outer wall of the metamaterial pipeline matrix 100 through the elastic bearing rings 200. The inner wall surface of the mass ring 300 is in contact with the outer wall surface of the elastic bearing ring 200, and the mass ring 300 is fixedly connected to the elastic bearing ring 200. The mass ring 300 forms a "mass-spring" resonance system through the elastic bearing rings 200 provided at both ends, which can generate a significant local resonance effect in the target low-frequency band (such as below 200 Hz). After this resonance system is coupled with the metamaterial pipeline matrix 100, an elastic wave bandgap can be formed within a specific frequency range, effectively blocking the propagation of low-frequency vibrations (such as pump shaft frequency and blade frequency) generated by equipment such as pumps along the pipeline. The close-fitting design of the inner wall of the mass ring 300 and the outer wall of the elastic bearing ring 200 ensures an efficient transmission path for vibration energy from the metamaterial pipeline matrix 100 to the elastic bearing ring 200 to the mass ring 300. The vibration kinetic energy is converted into elastic potential energy through the inertial action of the mass ring 300 and dissipated in the elastic bearing ring 200, avoiding the limitation that traditional damping materials are only effective in the high-frequency band. The arrangement of the two elastic bearing rings 200 symmetrically distributed at both ends of the mass ring 300 forms a double-support structure axially, which not only ensures the radial vibration freedom of the mass ring 300 (beneficial for resonance tuning) but also suppresses unexpected transverse vibration modes through symmetric constraints, improving the structural reliability of the vibration absorber under complex working conditions. The elastic bearing ring 200 is directly fixed to the outer wall of the pipeline, and modular installation can be achieved without changing the existing pipeline structure. The fixed connection between the mass ring 300 and the elastic bearing ring 200 adopts conventional processes such as mechanical fastening or welding, which not only ensures the connection strength but also adapts to the installation requirements of different pipe diameters, significantly improving the engineering applicability. The modular design provides a basic platform for the integration of subsequent additional oscillator modules. The mass ring 300 not only serves as the main oscillator mass block, but its outer surface can also be used as the installation matrix for the additional oscillator module. By changing the density / volume of the mass ring 300 or the stiffness of the elastic bearing ring 200, the basic resonance frequency band can be preset, providing design freedom for the precise adjustment of the bandgap. While ensuring the low-frequency vibration absorption performance, it also takes into account installation reliability, working condition adaptability, and subsequent expandability, providing a basic solution for the vibration control of the equipment pipeline system.

[0028] Such as Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, in this embodiment, the quality ring 300 is formed by the relative snap - fit connection of two half - ring units. Through the split - type half - ring unit design, it can be directly snap - fitted onto the laid pipeline without disassembling the pipeline, solving the installation problem that the traditional integral quality ring must be sleeved from the end of the pipeline, and is particularly suitable for the transformation of pipeline systems with limited space or already in use. The two half - ring units adopt a symmetric snap - fit structure, which can generate uniform contact pressure circumferentially during the fastening connection, ensuring that there is no local stress concentration on the fitting surface between the quality ring 300 and the elastic bearing ring 200, and avoiding the problem of reduced vibration energy transfer efficiency caused by poor contact. The symmetric snap - fit structure makes the mass distribution of the quality ring 300 have strict axial symmetry, and no additional eccentric centrifugal force will be generated during the vibration process, effectively preventing secondary vibration caused by mass imbalance and ensuring the stability of the vibration absorber. The split - type design allows individual disassembly and replacement of damaged half - ring units without replacing the entire quality ring 300, significantly reducing the maintenance cost. When it is necessary to adjust the quality parameters, the quality can also be finely adjusted by replacing half - ring units of different materials. The snap - fit connection uses a concave - convex fit structure or a strengthened connector, which ensures the overall structural integrity of the quality ring 300 under high - frequency vibration conditions while ensuring the convenience of split installation, and avoids the attenuation of vibration absorption performance caused by loosening of the connection part. Optionally, the two half - ring units are relatively snap - fitted and connected by using countersunk screw holes 1200 and bolts. Optionally, the two half - ring units are relatively snap - fitted and connected by using a flange.

[0029] As Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, in this embodiment, the additional oscillator module is arranged on the mass ring 300 via a sliding module; the sliding module includes a slide rail 400, a connecting clamping ring 500, and a locking member 600. The slide rail 400 is arranged along the axial direction of the mass ring 300 on the outer wall surface of the mass ring 300, and multiple slide rails 400 are arranged at equal intervals along the circumferential direction of the mass ring 300; the connecting clamping ring 500 is arranged around the mass ring 300 along the circumferential direction of the mass ring 300 and is fixedly connected to the additional oscillator module, and the connecting clamping ring 500 and the additional oscillator module are jointly slidably connected to the slide rail 400. The locking member 600 is arranged along the radial direction of the mass ring 300, and by rotating the locking member 600, the connecting clamping ring 500 and / or the additional oscillator module is locked on the mass ring 300. The sliding cooperation between the multiple parallel slide rails 400 arranged along the circumferential direction and the connecting clamping ring 500 enables the additional oscillator module to achieve continuous adjustment of the axial position on the mass ring 300. By changing the position of the additional oscillator module, the resonance frequency of the overall system can be precisely controlled to achieve dynamic matching of the vibration absorption frequency band. The design of the slide rails 400 arranged at equal intervals along the circumferential direction allows the additional oscillator module to be selectively arranged in the circumferential direction. By configuring the additional oscillator module on different slide rails 400, specific-order vibration modes can be selectively excited to achieve synchronous absorption of vibration energy in multiple directions, solving the problem that traditional single-point tuning is difficult to suppress multi-dimensional vibration. The radial locking mechanism of the locking member 600 allows for quick locking and quick unlocking while ensuring the adjustment accuracy. When the working conditions of the pipeline system change (such as the vibration spectrum shifting due to a change in fluid pressure), the position of the additional oscillator module can be immediately adjusted to form the basis for a closed-loop control of "monitoring - adjustment - locking", significantly enhancing the adaptability under complex working conditions. The integrated design of the connecting clamping ring 500 and the additional oscillator module combines the sliding guiding function and the mass block fixing function into one, avoiding the additional installation space required by the traditional guide rail structure. With the compact layout of the radial locking member 600, while achieving the adjustable function, the overall structural thickness increases very little. Combining the modular and integrated structural design can further meet the installation requirements in space-limited scenarios. The locking member 600 adopts a mechanical radial pressing principle, converting the axial displacement generated by thread rotation into a radial locking force, forming a surface contact friction fixation between the connecting clamping ring 500 and the slide rail 400, which has a higher anti-loosening ability than traditional bolt lateral locking and can maintain the preset position unchanged in a continuous vibration environment, ensuring the reliability of long-term use.

[0030] As Figure 3 and Figure 4As shown, in this embodiment, two connecting snap rings 500 are respectively located at both ends of the mass ring 300 and are arranged oppositely. A synchronous driving mechanism is provided between the two connecting snap rings 500 to drive the two connecting snap rings 500 to slide relatively close or slide relatively away synchronously. The synchronous driving mechanism is used to forcibly control the symmetric movement of the two connecting snap rings 500, ensuring that the additional oscillator module always maintains an accurate axially symmetric position at both ends of the mass ring 300, eliminating the axial offset that may be generated by manual adjustment alone, and improving the adjustment accuracy of the vibration suppression frequency band. The synchronous reverse movement mechanism of the double connecting snap rings 500 ensures that the mass distribution is always symmetric about the midpoint of the mass ring 300, and no new mass eccentricity is introduced during the adjustment process, effectively avoiding the centrifugal force imbalance problem caused by traditional single-sided adjustment, and enabling the system to maintain stable vibration absorption performance. By precisely controlling the relative distance between the two connecting snap rings 500, the axial higher-order vibration modes (such as the axial second-order vibration mode) of the mass ring 300 can be specifically excited. When the spacing is a specific wavelength ratio, the vibrations of multiple characteristic frequencies can be synchronously suppressed, achieving the multi-band control effect under single-degree-of-freedom adjustment. The synchronous driving mechanism forcibly maintains the movement consistency of the double connecting snap rings 500 through a mechanical linkage device (such as a gear rack or a synchronous belt). Even if a single locking part 600 is slightly loose, the system can still maintain the basic working state through symmetric constraints, significantly improving the fault tolerance ability in harsh environments such as the battlefield. The problem of difficult to balance the accuracy and efficiency of the adjustable vibration absorber is solved through the motion coupling mechanism, ensuring that the vibration suppression frequency band of the equipment pipeline system can be quickly and accurately adjusted under complex working conditions.

[0031] As Figure 1 , Figure 3 and Figure 6As shown in the figure, in this embodiment, the synchronous drive mechanism includes a mounting boss 700, a gear 800, and a rack 900. The mounting boss 700 is disposed on the outer wall surface of the mass ring 300 and is at the central position between two connecting snap rings 500. The gear 800 is rotatably disposed on the mounting boss 700. Each connecting snap ring 500 is provided with a rack 900 arranged axially and the rack 900 is arranged towards the mounting boss 700. The racks 900 of the two connecting snap rings 500 are meshed with each other relatively on the gear 800 and the non-toothed edges of the racks 900 are limited by the mounting boss 700. By driving the gear 800 to rotate to drive the axial movement of the rack 900, the two connecting snap rings 500 are driven to slide synchronously closer or synchronously farther away. The meshing transmission between the gear 800 and the double racks 900 forms a strict motion coupling relationship, ensuring that the symmetric movement error of the two connecting snap rings 500 is small, thereby improving the adjustment accuracy. The inclined surface contact characteristic of the gear-rack meshing pair generates a self-locking effect, which can automatically resist the displacement deviation caused by vibration when no driving force is applied, and keeps the position fixed without an additional braking device, solving the technical pain point that the traditional sliding mechanism is prone to looseness. The symmetrically arranged double racks 900 generate axial driving forces that are equal in magnitude and opposite in direction when the gear 800 rotates, so that the two connecting snap rings 500 always bear balanced mutual forces, eliminating the lateral bending moment caused by unilateral driving and reducing the adjustment operation torque. The integrated design of the mounting boss 700 and the mass ring 300 highly integrates the gear 800 and the support structure. The limiting fit between the non-toothed edge of the rack 900 and the mounting boss 700 can still ensure the straightness of the movement without the traditional guide groove. Through the mechanical interlocking principle, the micron-level movement accuracy and the kilo-newton-level locking force are unified, ensuring the real-time precise regulation of the frequency band of the metamaterial vibration absorber in a complex vibration environment. Optionally, multiple groups of synchronous drive mechanisms are provided, and the multiple groups of synchronous drive mechanisms are arranged at equal intervals in the circumferential direction of the mass ring 300. Optionally, two groups of synchronous drive mechanisms are provided, and the two groups of synchronous drive mechanisms are arranged relatively. Optionally, as Figure 16 and Figure 17 shown, on the other side of the mass ring 300 relative to the synchronous drive mechanism, that is, on the opposite side of the synchronous drive mechanism, a guiding mechanism is arranged. The guiding mechanism includes a guiding rod 1300 and a guide groove table 1400. The guide groove table 1400 is disposed on the mass ring 300 and is arranged relatively to the mounting boss 700. The connecting snap ring 500 is provided with a guiding rod 1300 arranged axially along the connecting snap ring 500. The guiding rods 1300 of the two connecting snap rings 500 are arranged in a staggered manner, and the guiding rods 1300 are respectively slidably inserted into the sliding grooves of the guide groove table 1400. Through the cooperation of multiple groups of synchronous drive mechanisms, or the cooperation of the synchronous drive mechanism and the guiding mechanism, the mechanical balance is achieved, and then the precise and stable adjustment of the additional oscillator module is realized.

[0032] As Figure 1 、Figure 2 and Figure 5 As shown in Figure 5 , in this embodiment, the additional oscillator module includes a plurality of cantilever units. The cantilever units are arranged on the connecting snap ring 500 along the axial direction of the connecting snap ring 500, and the cantilever ends are arranged on the side away from the mass ring 300. The plurality of cantilever units are arranged at equal intervals along the circumferential direction of the connecting snap ring 500. The cantilever structure of the cantilever unit forms a distributed mass-spring system in the axial and circumferential directions. When the connecting snap ring 500 moves axially, the cantilever unit and the mass ring 300 generate multi-order coupled resonance, forming a plurality of suppression frequency bands. The circumferentially equally spaced cantilever units form a periodic structure, and its vibration mode matches the circumferential wave number of the pipeline. The cantilever length and the cross-sectional moment of inertia of the cantilever unit constitute an equivalent stiffness. When the effective length is changed by axial movement, the system simultaneously realizes the dual tuning effects of mass redistribution and stiffness reconstruction, so that a single adjustment action can simultaneously change multiple characteristic frequencies, thereby improving the adjustment efficiency.

[0033] As Figure 1 shown, in this embodiment, the cantilever units on the two connecting snap rings 500 are arranged in one-to-one correspondence; or the cantilever units on the two connecting snap rings 500 are arranged in relative dislocation; or the number of cantilever units on the two connecting snap rings 500 is the same; or the number of cantilever units on the two connecting snap rings 500 is different. The vibration modes of the cantilever units arranged in one-to-one correspondence are precisely matched. The cantilever units on the two connecting snap rings 500 are axially aligned to form a symmetric periodic mass distribution, which can accurately excite the axially symmetric vibration mode, especially achieve insertion loss for the low-frequency vibration caused by the fluid pressure pulsation in the pipeline, and can maintain phase consistency to avoid mode interference. The wide-band suppression of the misaligned arrangement of the cantilever units. The cantilever units are relatively misaligned, and the system simultaneously excites the axial and circumferential coupling modes, forming a plurality of separated suppression frequency bands, which can synchronously suppress the combined vibrations such as the blade frequency of the pump and the pipeline bending mode. The mass ratio optimization design of the arrangement of the same number of cantilever units. Keeping the number of cantilever units on the double snap rings equal, the total mass distribution of the system is strictly symmetric, avoiding the additional centrifugal force caused by mass imbalance. The arrangement of different numbers of cantilever units realizes asymmetric frequency band compensation. By configuring different numbers of cantilever units, an asymmetric vibration suppression curve is formed on both sides of the natural frequency of the system, which can specifically compensate for the uneven vibration energy distribution of the pipelines of specific equipment. Through the design of different arrangement modes of the cantilever units, a single vibration absorber structure can be adapted to pipeline systems with different vibration spectrum characteristics, and the vibration suppression strategy can be quickly reconstructed under harsh working conditions such as submarines and spacecraft, improving the applicability compared with the traditional fixed design.

[0034] As Figure 1 、 Figure 2 and Figure 5As shown in the figure, in this embodiment, the cantilever unit includes a cantilever beam 1000 and a tip mass 1100. The tip mass 1100 is located at the cantilever end of the cantilever beam 1000. The connecting end of the cantilever beam 1000 is slidably connected to the slide rail 400 and fixedly connected to the corresponding connecting snap ring 500. The cantilever beam 1000 provides equivalent stiffness, and the tip mass 1100 provides concentrated mass, constituting a tunable "spring-mass" system. By sliding and adjusting to change the effective length l of the cantilever beam 1000, the natural frequency and modal vibration mode of the system can be changed simultaneously, realizing dual-degree-of-freedom tuning under single-parameter adjustment, and expanding the low-frequency vibration suppression bandwidth below 200 Hz. After the bending vibration of the cantilever beam 1000 is coupled with the radial vibration of the mass ring 300, the vibration modes above the second order of the system can be excited, forming an additional vibration suppression band to make up for the deficiency of the traditional local resonance structure in suppressing medium and high frequencies, and improving the overall insertion loss. The concentrated arrangement of the tip mass 1100 forms a radial mass gradient distribution, and its moment of inertia can effectively suppress the circumferential torsional vibration of the pipeline. When the cantilever beam 1000 slides axially, a controllable spatial interference effect is generated between the tip mass 1100 at its end and the adjacent cantilever unit.

[0035] In this embodiment, the cantilever beam 1000 and / or the tip mass 1100 are metal material parts; and / or the mass ring 300 is a metal material part, and the elastic bearing ring 200 is a viscoelastic material part. The metal cantilever beam 1000, tip mass 1100 and mass ring 300 form a high-stiffness bearing framework to ensure that the vibration absorber does not undergo plastic deformation or fracture under long-term vibration loads. The elastic bearing ring 200 made of viscoelastic material absorbs impact energy through flexible deformation. The two work together to solve the problems of easy fatigue cracking of traditional all-metal structures and insufficient load-bearing capacity of all-polymer structures. The metal components generate low-frequency local resonance band gaps through high-density mass blocks and rigid beam structures. The viscoelastic material dissipates medium and high-frequency vibration energy through molecular chain friction. The rigid-flexible coupling design breaks through the defect of limited frequency bands of a single material and realizes full-band vibration control. The metal components ensure the dimensional stability under high / low temperature conditions and avoid the thermal expansion or embrittlement failure of polymer materials. The elastic bearing ring 200 of the viscoelastic material compensates for the difference in thermal expansion coefficients of different materials through large deformation ability, so that the overall structure maintains stable performance. The vibration kinetic energy of the metal mass ring 300 and the cantilever beam 1000 is converted into heat energy through the shear deformation of the viscoelastic layer, forming a multi-stage dissipation path of "kinetic energy-elastic potential energy-heat energy". Compared with the single resonance energy consumption of a pure metal structure, the energy conversion efficiency is improved. The high reflection characteristics of the metal components for structural sound waves are combined with the absorption characteristics of the viscoelastic material for air sound waves to simultaneously suppress vibration transmission and noise radiation, meeting the special requirements of concealment. Through the complementary optimization of physical properties, the synergistic improvement of vibration suppression performance, environmental adaptability and engineering reliability is realized without the need to introduce complex active control.

[0036] During implementation, a metamaterial pipeline vibration absorber structure with adjustable bandgap is provided for suppressing low-frequency vibration of pipelines. This structure consists of a main oscillator module and an additional oscillator module with adjustable frequency. The main body structure is a metamaterial pipeline matrix 100, two elastic bearing rings 200, a mass ring 300, and a metamaterial pipeline vibration absorber unit composed of eight groups of slidable "cantilever beam 1000 - tip mass 1100" oscillators. The metamaterial pipeline vibration absorber structure is installed on the outer wall of the metamaterial pipeline matrix 100. The main oscillator module is composed of a mass ring 300 and two elastic bearing rings 200. The inner walls at both ends of the mass ring 300 are fixedly connected to the outer walls of the elastic bearing rings 200, and the inner walls of the two elastic bearing rings 200 are fixedly connected to the outer wall of the pipeline. Four slide rails 400 are evenly arranged along the circumference of the mass ring 300. The additional oscillator module is composed of eight groups of slidable "cantilever beam 1000 - tip mass 1100". One end of the cantilever beam 1000 is installed in the slide rail 400 of the mass ring 300. Four groups of "cantilever beam 1000 - tip mass 1100" structures are installed at each end of the mass ring 300. The four cantilever beams 1000 are connected in parallel through a connecting collar 500 to achieve synchronous sliding in the slide rail 400. A rack 900 is provided on the connecting collar 500. By meshing the gear 800 installed in the middle of the mass ring 300 with the rack 900, synchronous adjustment of the position of the additional oscillator module can be achieved, and the bandgap frequency of the metamaterial pipeline vibration absorber structure can be adjusted by sliding. The effective suppression of pipeline vibration in the low-frequency band can be achieved through the local resonance bandgap of the metamaterial pipeline vibration absorber structure. By rotating the gear 800 to adjust the extended length of the cantilever beam 1000, the resonance frequency of the additional oscillator module can be adjusted, and then the dynamic tuning of the bandgap position can be realized to precisely suppress pipeline vibration in different frequency bands. By mechanically sliding to adjust the resonance frequency of the additional oscillator, the bandgap range is dynamically broadened to solve the contradiction between the fixed frequency band of traditional vibration absorbers and the complex and changeable pipeline vibration.

[0037] A metamaterial pipeline vibration absorber structure with adjustable bandgap is used for complex vibration control of pipelines. This metamaterial pipeline vibration absorber structure is arranged periodically or aperiodically along the pipeline, which can achieve the suppression of multi-directional bending vibrations such as in-plane and out-of-plane of the pipeline surface. Moreover, the dynamic adjustment of the vibration suppression frequency band can be realized by adjusting the position of the additional oscillator, and precise control can be carried out according to the vibration characteristics of different pipelines or the vibration characteristics of the same pipeline under different working conditions. Precise control of complex pipeline vibration can be achieved under relatively wide frequency conditions to meet the vibration suppression requirements under various working conditions, so as to solve the problem that it is difficult to achieve precise vibration suppression for different pipelines under different working conditions.

[0038] The structure of a metamaterial pipeline vibration absorber with adjustable bandgap includes a main oscillator module and an additional oscillator module. The main oscillator module is fixedly installed on the outer wall of the metamaterial pipeline matrix 100 through bolts in the countersunk head screw holes. The additional oscillator module is fixed in the slide rails 400 around the main oscillator module. The additional oscillator modules are fixedly connected in parallel through the connecting snap rings 500. The synchronous movement of the additional oscillator module in the slide rails 400 is realized by the meshing rotation of the gear 800 and the rack 900, and the position of the additional oscillator module is fixed by the fastening bolts (locking parts 600) around the main oscillator module.

[0039] The main oscillator module consists of a mass ring 300 and two elastic bearing rings 200. The inner walls at both ends of the mass ring 300 are fixedly connected to the outer walls of the elastic bearing rings 200. The inner walls of the two elastic bearing rings 200 are fixedly connected to the outer wall of the metamaterial pipeline matrix 100. Four slide rails 400 are arranged at equal angles along the circumferential direction of the mass ring 300 for the installation and sliding of the additional oscillator module. An installation boss 700 is arranged in the middle part of the outer wall surface of the mass ring 300 for installing the gear 800 and the rack 900. The function of the main oscillator module is to generate a local resonance bandgap based on the local resonance effect of the metamaterial, effectively suppress the transmission of elastic waves in the pipeline, and achieve effective control of low-frequency vibration.

[0040] As Figure 3 and Figure 4 shown, the additional oscillator module is composed of eight slidable cantilever beams 1000 and eight tip mass blocks 1100, which are fixedly connected to form a "spring-mass" oscillator. The additional oscillator module is connected to the mass ring 300 through the slide rails 400 and can achieve adjustable frequency through sliding. By adjusting the position of the cantilever beam 1000, the frequency of the additional oscillator module can be changed. The additional oscillator modules at both ends of the mass ring 300 are symmetrically structured to ensure balanced and equivalent vibration suppression effects for in-plane and out-of-plane bending multi-directional vibrations of the pipeline. The function of the additional oscillator module is to generate an additional local resonance bandgap, effectively broaden the width of the vibration suppression bandgap of the metamaterial vibration absorber. At the same time, through the adjustable design of the structure, precise regulation of the bandgap can be achieved, so as to achieve precise suppression of vibrations under different pipeline conditions or the same pipeline under different working conditions. Among them, the local resonance bandgap refers to a certain frequency range. Elastic waves within the bandgap frequency range are suppressed and cannot propagate, while elastic waves outside the bandgap frequency band can propagate normally without being affected. The bandgap frequency range of the structure of the metamaterial pipeline vibration absorber is related to the natural frequency of the structure. When designing the metamaterial vibration absorber, the natural frequency of the metamaterial vibration absorber can be designed according to the vibration transmission characteristics of different pipelines, so as to effectively suppress pipeline vibration. In the frequency design of the main oscillator module, the mass of the mass ring can be changed by designing the structural parameters of the mass ring and selecting materials, and the elastic stiffness can also be adjusted by designing the structure and parameters of the elastic bearing ring. Through the coordinated and optimized design of the two, the frequency of the main oscillator module can be changed to generate a corresponding frequency band of the bandgap.

[0041] The quality ring 300 is composed of two identical semi-rings, which are fixedly connected to form a complete quality ring 300. The fixed connection can be achieved by bolts with countersunk holes, welding or other means. The quality ring 300 can be made of high-density metal materials (such as steel, copper, aluminum, lead). The inner wall surface is fixedly connected to the elastic bearing ring 200, and the two can be fixed by high-strength adhesives or by vulcanization. Four slidable rails 400 are evenly arranged along the circumferential direction of the quality ring 300. Bolt bosses and fastening bolts are provided at both ends of the rail 400. The cantilever beam 1000 in the additional oscillator module is installed on the quality ring 300 through the rail 400 and fixed by fastening bolts (locking parts 600). An installation boss 700 is provided at the middle position of the outer wall surface of the quality ring 300 for installing the gear 800 and the rack 900. Among them, the quality ring 300 can be made of metal or high-density materials, providing the mass part in the "spring-mass" oscillator, and the optional range includes copper, steel, lead, etc. The inner radius of the quality ring 300 is r3, the outer radius is r4, the length is l1, and four rails are evenly arranged along the middle of the circumferential direction of the quality ring. The height of the rail is h1, the width is b2, and the length is l1. Fastening bolts are provided on the outer sides of both ends of the rail for fixing the position of the cantilever beam. The elastic bearing ring is made of high-damping materials (damping ratio ζ≥0.1), providing the spring part in the "spring-mass" oscillator and providing damping. Silicon rubber, butyl rubber, natural rubber, etc. can be selected. The inner radius r2 of the elastic bearing ring is 54 mm, the outer radius r3 is 76 mm, and the width b1 is 15 mm. In addition, the high-damping effect of the elastic bearing ring material can achieve the attenuation of the pipeline vibration resonance peak, and can further improve the vibration reduction effect of the metamaterial absorber on the basis of the vibration reduction effect of the band gap.

[0042] As Figure 5As shown in the figure, the additional oscillator module of the metamaterial pipeline vibration absorber structure with adjustable bandgap is composed of a cantilever beam 1000 and a tip mass 1100. The two can also be equivalent to a "spring-mass" oscillator. When suppressing the elastic wave vibration of the pipeline, it can generate additional local resonance bandgaps on the basis of the original main oscillator bandgap, thereby broadening the width of the bandgap, and then effectively suppressing the multi-frequency vibration of the pipeline. Among them, the cantilever beam 1000 is a rectangular slender beam with a length of l2, a width of b2, and a height of h1. There is a card slot at one end for fixed connection with the connecting snap ring. Its material is metal, which can be steel, copper, aluminum or other alloy metals. Its main function is to provide the spring part in the "spring-mass" oscillator. The tip mass 1100 is a cuboid structure with a length of l3, a width of b2, and a height of h2. Its material is a high-density material, which can be steel, copper, lead and alloy metals or other materials with higher density. Its main function is to provide the mass part in the "spring-mass" oscillator. The two are fixedly connected and used as an additional oscillator module to be connected in the slide rail 400 of the mass ring 300. By changing the position of the cantilever beam 1000 in the slide rail 400, the elastic stiffness of the cantilever beam 1000 can be changed, so as to change the natural frequency of the additional oscillator module. By changing the natural frequency of the "cantilever beam-tip mass" additional oscillator module, a new bandgap position is added, so as to achieve precise suppression according to the vibration characteristics of the pipeline in engineering applications.

[0043] As Figure 6 shown in the figure, the sliding adjustment module of the metamaterial pipeline vibration absorber structure with adjustable bandgap is composed of a connecting snap ring 500, a rack 900 and a gear 800. The main function of the connecting snap ring 500 is to parallelize the four cantilever beams 1000 at one end of the mass ring 300, so as to realize the synchronous sliding of the additional oscillator module in the slide rail 400 of the mass ring 300. The main functions of the rack 900 and the gear 800 are to adjust the position of the additional oscillator module and the extension length of the cantilever beam 1000 through the meshing rotation of the gear 800 and the rack 900, so as to realize the precise control of the frequency of the additional oscillator module. Among them, the connecting snap ring 500, the gear 800 and the rack 900 are made of metal materials, which can be steel, copper, aluminum or other alloy metals. The inner radius of the connecting snap ring 500 is r4, the outer radius is r5, and the width is b3. There is a boss with a width of b4 on the outside of the connecting snap ring for the installation and fixation of the rack. The length of the rack is l3.

[0044] The mass ring 300 of the metamaterial pipeline vibration absorber structure can be divided into two semi-circular ring structures, and the six countersunk screw holes 1200 on both sides of the two semi-circular rings are connected by bolts. The outer wall surfaces of the two elastic bearing rings 200 are fixedly connected to the inner wall surface of the mass ring 300, and the two can be fixed by a high-strength adhesive (shear strength ≥ 15 MPa, tensile strength ≥ 20 MPa), or fixed by vulcanization. The inner wall surface of the elastic bearing ring 200 is connected to the outer wall surface of the metamaterial pipeline matrix 100 and is clamped on the metamaterial pipeline matrix 100 through the fastening action of the bolts in the countersunk screw holes to ensure the structural stability. Eight additional oscillator modules composed of cantilever beams 1000 and eight tip mass blocks 1100 are respectively installed in the slide rails 400 on the outside of the mass ring 300, with four groups of additional oscillator modules installed at each end. The cantilever beams 1000 are inserted into the slide rails 400 and fixed in position by fastening bolts. The cantilever beams 1000 can slide in the slide rails 400 to change the stiffness of their equivalent springs, realizing precise regulation of the bandgap position of the metamaterial vibration absorber.

[0045] The additional oscillator modules are connected in parallel through two connecting snap rings 500. Each connecting snap ring 500 connects four cantilever beams 1000. A slot is provided at one end of the cantilever beam 1000 for the installation and fixation of the connecting snap ring 500. A rack 900 is provided on one side of the connecting snap ring 500, and the racks 900 of the two connecting snap rings 500 are simultaneously engaged with the gear 800 installed in the middle of the outer wall surface of the mass ring 300. The position of the additional oscillator module in the slide rail 400 is moved by the rotation of the gear 800.

[0046] The elastic bearing ring 200 can be made of one or a combination of viscoelastic materials such as butyl rubber, silicone rubber, and natural rubber, and can achieve broadband and efficient suppression of resonance peaks in the pipeline through the damping effect. The elastic bearing ring 200 is a circular ring structure and is installed on the outer wall surface of the metamaterial pipeline matrix 100. The inner side of the elastic bearing ring 200 is connected to the outer wall surface of the metamaterial pipeline matrix 100, and the outer side is connected to the inner wall surface of the mass ring 300.

[0047] The cantilever beam 1000 can be made of metal materials such as steel and copper. The cantilever beam 1000 is a square beam structure and is installed in the slide rails 400 around the mass ring 300. It is connected in parallel through the connecting snap ring 500 to realize synchronous sliding of multiple cantilever beams 1000, and the position is fixed by fastening bolts (locking parts 600).

[0048] The tip mass block 1100 can be made of high-density metal materials (such as steel, copper, aluminum, lead). The structure of the tip mass block 1100 is a cuboid structure and is installed at one end of the cantilever beam 1000. The two can be fixed by welding or a well-known and commonly used high-strength adhesive.

[0049] The number of the metamaterial pipeline vibration absorber structures is multiple, such as Figure 7and Figure 14 As shown. Optionally, the metamaterial pipeline vibration absorber structures are arranged periodically on the metamaterial pipeline matrix 100 at a certain interval l. By designing the interval l period, at this time, the Bragg frequency of the pipeline structure is close to the natural frequency of the metamaterial pipeline vibration absorber, and the Bragg bandgap of the pipeline matrix and the local resonance bandgap of the metamaterial vibration absorber reach the coupling condition, forming a relatively wide coupling bandgap, and effectively broadening the vibration suppression bandgap of the metamaterial pipeline vibration absorber.

[0050] Based on the local resonance mechanism of metamaterials and the bandgap adjustable design method, the present invention proposes a structure of a metamaterial pipeline vibration absorber with adjustable bandgap, and specifically designs the resonance frequencies of the main oscillator module and the additional oscillator module of the metamaterial pipeline vibration absorber, which can effectively suppress the low-frequency vibration of the pipeline under the condition of light weight. In addition, through the adjustable design of the position of the additional oscillator module, the precise control of the pipeline vibration suppression frequency band can be realized. The present invention can be applied to the vibration suppression of pipeline systems of various equipment, such as pipeline systems of transportation vehicles (ships, rail vehicles, aircraft, spacecraft, new energy vehicles, etc.), pipeline systems of modern industrial engineering (substations, natural gas stations, tunnels, subway stations, etc.) and pipeline systems of smart homes (central air conditioners, refrigerators, washing machines, fresh air systems, etc.).

[0051] The present invention can generate two adjustable local resonance bandgaps in the low-frequency range below 150 Hz, including a wide frequency bandgap with a bandwidth exceeding 50 Hz. At the same time, it can precisely control the bandgap frequency band by adjusting the structure of the metamaterial pipeline vibration absorber, realizing the precise control of vibrations in different frequency bands, and showing good vibration control effects. The present invention designs the structure of the metamaterial pipeline vibration absorber based on the local resonance mechanism and the bandgap adjustable design method. First, based on the local resonance mechanism, the main oscillator module and the additional oscillator module of the metamaterial pipeline vibration absorber structure are designed. Both the main oscillator module and the additional oscillator module can generate local resonance bandgaps, achieving the effect of "controlling large wavelengths with small sizes" based on the local resonance mechanism. Secondly, based on the design principle of adjustable bandgap, the movable design of the additional oscillator is carried out. By precisely controlling the position of the additional oscillator, the precise control of the vibration of the pipeline under different working conditions is realized. The present invention can overcome the defects in the prior art that cannot have high reliability, low cost, and good vibration reduction performance in the low-frequency broadband range. At the same time, aiming at the problem that the vibration characteristics of different pipeline systems or the same pipeline system under different working conditions are complex and difficult to control, the present invention designs an additional oscillator module with adjustable position in the metamaterial pipeline vibration absorber. By adjusting the frequency of the additional oscillator, the adjustable design of the vibration suppression frequency band is realized, and a new adjustable bandgap is introduced on the basis of the original bandgap of the main oscillator module, realizing the effective control of the complex vibration of the pipeline under the condition of light weight.

[0052] The low-frequency vibration damping characteristics of the metamaterial pipeline vibration absorber structure are excellent. Based on the local resonance bandgap mechanism of metamaterials and according to the complex vibration characteristics of actual engineering pipelines, the present invention specifically designs the vibration suppression bandgap of the metamaterial pipeline vibration absorber structure. The proposed metamaterial pipeline vibration absorber structure can effectively suppress the low-frequency vibration of the pipeline under the conditions of small size and small additional mass, and further improves the pipeline vibration suppression efficiency by equidistant periodic arrangement or non-equidistant arrangement.

[0053] The bandgap frequency of the metamaterial pipeline vibration absorber structure is dynamically adjustable, and precise control of the bandgap frequency band can be achieved. The present invention synchronously adjusts the position of the cantilever beam 1000 through a gear-rack structure to change the frequency of the additional oscillator, realizing the adjustable design of the vibration suppression frequency band. Furthermore, multiple vibration suppression bandgaps can be generated in different frequency bands of the pipeline, achieving precise design of the complex vibration of the pipeline.

[0054] The vibration suppression frequency band of the metamaterial pipeline vibration absorber structure has obvious broadband characteristics. By adjusting parameters such as the position of the cantilever beam 1000, the mass of the tip mass 1100, and the material of the elastic bearing ring 200, the present invention makes the bandgap generated by the main oscillator module gradually approach the bandgap generated by the additional oscillator, resulting in bandgap coupling, broadening the vibration damping frequency band, and suppressing the newly added resonance peaks.

[0055] The damping vibration damping characteristics of the metamaterial pipeline vibration absorber structure are excellent. The elastic bearing ring 200 proposed by the present invention can be made of a polymer damping material. By introducing a polymer super-damping material into the metamaterial pipeline vibration absorber structure, on the one hand, it can effectively attenuate the resonance peaks of the pipeline system, achieving a better vibration suppression effect; on the other hand, it can effectively broaden the width of the vibration bandgap, improving the engineering application value of this structure.

[0056] Example 1: In this example, the pipeline vibration transfer characteristics and energy band structure of a metamaterial pipeline vibration absorber structure with adjustable bandgap are simulated and calculated, and the calculation results are as Figure 8 、 Figure 9 shown. Among them, the outer radius r2 of the metamaterial pipeline matrix 100 is 54 mm, the inner radius r1 is 50 mm, the length a is 1.8 m, and its material is steel (with a density of 7850 kg / m³, Young's modulus of 2×10 11 Pa, and Poisson's ratio of 0.3); the inner radius r2 of the elastic bearing ring 200 is 54 mm, the outer radius r3 is 76 mm, the width b1 is 15 mm, and its material is rubber (with a density of 1300 kg / m³, Young's modulus of 2×10 7Pa, with a Poisson's ratio of 0.492 and a damping ratio of 0.15); the inner radius r3 of the mass ring is 76 mm, the outer radius r4 is 88 mm, and the length l1 is 250 mm. Its material is steel. Four slide rails 400 are evenly arranged in the middle of the 300 circumferences of the mass ring. The height h1 of the slide rail 400 is 5 mm, the width b2 is 20 mm, and the length l1 is 250 mm; the height h1 of the cantilever beam slide rail is 5 mm, the width b2 is 20 mm, and the length l2 is 230 mm. Its material is steel; the height h2 of the tip mass is 43 mm, the width b2 is 20 mm, and the length l3 is 60 mm. Its material is steel. The inner radius r4 of the connecting collar is 88 mm, the outer radius r5 is 90 mm, and the width b3 is 10 mm. The width b4 of the boss provided on the outer side of the connecting collar is 38 mm. Its material is steel. The number of teeth of the rack is 17, the addendum height is 2 mm, the dedendum height is 2.5 mm, the tooth width is 5 mm, the tooth thickness is 3.142 mm, the rack length l3 is 103.142 mm, the number of teeth of the gear is 18, the pitch diameter is 36 mm, the addendum circle diameter is 40 mm, the dedendum circle diameter is 31 mm, the base circle diameter is 33.829 mm, the addendum height is 2 mm, the dedendum height is 2.5 mm, the tooth width is 5 mm, and the tooth thickness is 3.142 mm.

[0057] The main oscillator module is directly connected to the metamaterial pipeline matrix 100, and two elastic bearing rings 200 are fixed on the outer wall surface of the metamaterial pipeline matrix 100 (see Figure 2 ). The outer wall surface of the elastic bearing ring 200 is fixedly connected to the inner wall surface of the mass ring 300. Each mass ring 300 is composed of two half rings. There are three countersunk screw holes 1200 (with a diameter of 4 mm) on the upper and lower sides of each half ring. The two half rings are fixedly connected by bolts through the six countersunk screw holes 1200.

[0058] The additional oscillator module is connected to the mass ring 300 through the slide rail 400. Among them, one end of the cantilever beam 1000 of the additional oscillator module is inserted into the slide rail 400. The four cantilever beams 1000 at one end of the slide rail 400 are connected in parallel through the connecting collar 500, and the four cantilever beams 1000 can slide synchronously along the slide rail 400. A rack 900 is provided on one side of the connecting collar 500, and a gear 800 is provided at the middle position of the outer wall surface of the mass ring 300. The connecting collars 500 on both sides of the slide rail 400 are meshed with both sides of the gear 800 through the rack 900 respectively. By rotating the gear 800, the cantilever beams 1000 at both ends of the slide rail 400 can slide synchronously, and finally the position of the cantilever beam 1000 is fixed by the fastening bolt (locking part 600). The other end of the cantilever beam 1000 is fixedly connected to the tip mass 1100, and the two are connected by gluing. Four cantilever beams 1000 are installed on each side of each mass ring 300. According to the vibration transmission characteristics of the metamaterial pipeline matrix 100, the extension length l of the cantilever beam 1000 in the structure of the metamaterial pipeline vibration absorber is adjusted. In the first embodiment, the extension length l of the cantilever beam is 150 mm.

[0059] The present invention performs simulation calculations on the energy band structure and vibration transmission characteristics of Example 1. First, a finite element simulation calculation is carried out on the energy band structure of the metamaterial pipeline vibration absorber structure. During the simulation calculation, first, an adaptive mesh division strategy is adopted to refine the mesh in the key areas. Second, Bloch-Floquet periodic boundary conditions are applied to the two ends of the metamaterial pipeline vibration absorber to simulate an infinite periodic structure. By traversing and scanning, the dispersion curve of the periodic structure is obtained. The expression of the Bloch-Floquet periodic boundary condition is: ; In the formula, r is the position vector, a is the lattice constant, and k is the Bloch wave vector. This boundary condition simplifies the eigenvalue solution problem of the infinite periodic structure to that of a unit cell model. The characteristic frequency ωn(k) changing with the wave vector constitutes the energy band curve. The energy band structure of the metamaterial vibration absorber structure is as shown in Figure 8 . In Example 1, the metamaterial pipeline vibration absorber structure can generate two band gaps of 51 Hz - 108 Hz and 125 Hz - 135 Hz in the low-frequency band below 200 Hz, effectively broadening the vibration suppression bandwidth of the dynamic vibration absorber under the same mass condition.

[0060] To further verify its vibration suppression performance, the present invention conducts a simulation test on the vibration transmission characteristics of the metamaterial pipeline vibration absorber structure. The test object is a pipeline composed of four periodically arranged metamaterial pipeline vibration absorber structures with adjustable band gaps ( Figure 7 shown), Figure 9 which is the comparison of the vibration transmission rates of the pipeline installed with the metamaterial pipeline vibration absorber structure and the pure pipeline without the absorber. As can be seen from Figure 9 , the metamaterial pipeline vibration absorber structure shows effective vibration attenuation effects in the frequency bands of 50 Hz - 108 Hz and 121 Hz - 130 Hz, and the maximum vibration attenuation can reach 20 dB, achieving effective control of the low-frequency vibration of the pipeline system. In addition, the simulation calculation results show that the vibration suppression frequency band of the pipeline installed with the metamaterial pipeline vibration absorber structure is basically the same as the band gap frequency band shown in the above energy band structure calculation results, which further verifies the accuracy of the above calculations. Finally, the simulation calculation results show that in addition to the effective suppression of the vibration within the band gap frequency band, the resonance peaks of the pipeline vibration are effectively attenuated. This is because the elastic bearing ring 200 is made of a high-damping rubber material, further improving the vibration suppression characteristics of the metamaterial pipeline vibration absorber.

[0061] In summary, the metamaterial pipeline vibration absorber structure can effectively suppress the low-frequency vibration of the pipeline, providing effective technical support for the precise control of the complex vibration of the equipment pipeline.

[0062] Example 2: In this example, the calculation results of the pipeline vibration transfer rate of the additional oscillator module of the metamaterial pipeline vibration absorber structure under different position conditions are given. At this time, the outer radius r2 of the metamaterial pipeline matrix 100 is 54 mm, the inner radius r1 is 50 mm, and the length a is 1.8 m. Its material is steel (with a density of 7850 kg / m³, a Young's modulus of 2×10 11 Pa, and a Poisson's ratio of 0.3); the inner radius r2 of the elastic bearing ring 200 is 54 mm, the outer radius r3 is 76 mm, and the width b1 is 15 mm. Its material is rubber (with a density of 1300 kg / m³, a Young's modulus of 2×10 7 Pa, a Poisson's ratio of 0.492, and a damping ratio of 0.15); the inner radius r3 of the mass ring is 76 mm, the outer radius r4 is 84 mm, and the length l1 is 250 mm. Its material is steel. Four slide rails 400 are evenly arranged in the middle along the circumferential direction of the mass ring. The height h1 of the slide rail 400 is 5 mm, the width b2 is 20 mm, and the length l1 is 250 mm; the height h1 and width b2 of the cantilever beam 1000 and the slide rail 400 are 5 mm and 20 mm respectively, and the length l2 is 200 mm. Its material is steel; the height h2 of the tip mass 1100 is 43 mm, the width b2 is 20 mm, and the length l3 is 60 mm. Its material is steel. The inner radius r4 of the connecting clamp ring is 88 mm, the outer radius r5 is 90 mm, and the width b3 is 10 mm. The width b4 of the boss provided on the outside of the connecting clamp ring is 38 mm. Its material is steel. The number of teeth of the rack is 17, the addendum height is 2 mm, the dedendum height is 2.5 mm, the tooth width is 5 mm, the tooth thickness is 3.142 mm, the rack length l3 is 103.142 mm, the number of teeth of the gear is 18, the pitch diameter is 36 mm, the addendum circle diameter is 40 mm, the dedendum circle diameter is 31 mm, the base circle diameter is 33.829 mm, the addendum height is 2 mm, the dedendum height is 2.5 mm, the tooth width is 5 mm, and the tooth thickness is 3.142 mm.

[0063] In this embodiment, the bandgap regulation characteristics of the metamaterial pipeline vibration absorber are tested. During the simulation calculation process, four metamaterial pipeline vibration absorber structures are arranged in a periodic manner. Keeping the other material parameters and structural parameters unchanged, the gear is rotated to make the additional oscillator module slide, and only the extension length l of the cantilever beam 1000 in the metamaterial pipeline vibration absorber is changed. The schematic diagram of its structural change is as shown in Figure 10 Figure. In this embodiment, the vibration transfer rate curves of the pipeline under different conditions such as the extension length l of the cantilever beam 1000 being l = 140 mm, l = 150 mm, l = 160 mm, and l = 170 mm are calculated respectively. The calculation results are as shown in Figure 11 Figure.

[0064] As shown in Figure 11As shown, in the frequency range below 200 Hz, the bandgap frequency band of the metamaterial pipeline vibration absorber structure changes significantly with the change of the length l of the cantilever beam 1000. At the same time, this metamaterial pipeline vibration absorber structure can effectively suppress the vibration within each bandgap frequency band, and the highest vibration attenuation effect can reach 26 dB. The calculation results show that with the change of the protruding length l of the cantilever beam 1000, the position of the local resonance bandgap frequency band generated by the additional oscillator module also moves continuously. With the increase of the protruding length l of the cantilever beam 1000, the additional bandgap (the second bandgap) frequency band of the metamaterial pipeline vibration absorber structure gradually moves to the low frequency. This is because the larger the protruding length l of the cantilever beam 1000 in the additional oscillator module, the smaller the elastic stiffness provided, the resonance frequency of the additional oscillator module gradually decreases, and the bandgap frequency band gradually moves to the low frequency. By adjusting the position of the cantilever beam 1000, the metamaterial pipeline vibration absorber structure can effectively control the vibration in the frequency range of 46 Hz - 145 Hz, broadening the vibration suppression bandwidth of the metamaterial pipeline vibration absorber structure. In addition, by adjusting the protruding length of the cantilever beam 1000 of the metamaterial pipeline vibration absorber structure, the vibration suppression bandgap frequency band can be accurately regulated to effectively control the complex vibration of the pipeline.

[0065] Embodiment III In this example, the calculation results of the vibration transfer characteristics of a specific square metamaterial pipeline vibration absorber are given. To further verify the vibration suppression characteristics of the metamaterial pipeline vibration absorber for various pipelines with different configurations in engineering practice, such as Figure 12 and Figure 13 As shown, in this embodiment, a square pipeline commonly used in engineering practice is used as the vibration control object for simulation testing, and the sliding adjustment module is omitted in the simulation calculation here. Among them, the metamaterial pipeline matrix 100 uses a square pipeline structure. The outer side length c1 of the cross-section of the square pipe is 88 mm, the wall thickness t1 is 4 mm, the length l is mm, and the material is steel (its density is 7850 kg / m³, Young's modulus is 2×10 11 Pa, and the Poisson's ratio is 0.3); the elastic bearing ring 200 is a square hollow ring structure. The outer side length c2 of the cross-section of its square hollow is 108 mm, the wall thickness t2 is 10 mm, the length b1 is 15 mm, and its material is rubber (its density is 1300 kg / m³, Young's modulus is 2×10 7Pa, with a Poisson's ratio of 0.492 and a damping ratio of 0.15); the mass ring 300 is a square hollow ring structure, with the outer side length c3 of its square hollow cross-section being 132 mm, the wall thickness t3 being 12 mm, the length l1 being 250 mm, and its material being steel; four slide rails 400 are evenly arranged in the middle along the circumferential direction of the mass ring 300, the height h1 of the slide rail 400 being 5 mm, the width b2 being 20 mm, and the length l1 being 250 mm (the same as in the first embodiment); the height h1 of the cantilever beam 1000 and the slide rail 400 is 5 mm, the width b2 is 20 mm, and the length l2 is 200 mm, and its material is steel (the same as in the first embodiment); the height h2 of the tip mass 1100 is 43 mm, the width b2 is 20 mm, and the length l3 is 60 mm, and its material is steel (the same as in the first embodiment).

[0066] Arrange four metamaterial pipeline vibration absorbers in a periodic pattern on the square pipeline, with the interval a being 1.8 m and the total length of the pipe section being 7.2 m. Form a square pipeline structure with the metamaterial pipeline vibration absorbers installed as shown in Figure 12 and Figure 13 According to the vibration transfer characteristics of the pipeline matrix, adjust the protruding length l of the cantilever beam in the metamaterial pipeline vibration absorber. In the third embodiment, the protruding length l of the cantilever beam is 160 mm.

[0067] The present invention performs a simulation calculation on the vibration transfer characteristics of the pipeline in the third embodiment. The simulation calculation method is the same as that in the first embodiment, and the calculation results are as shown in Figure 14 shown, Figure 14 is the comparison of the vibration transfer ratios of the square pipeline with the metamaterial pipeline vibration absorbers installed and the square pipeline without the vibration absorbers. It can be seen from Figure 14 that the metamaterial pipeline vibration absorber shows an effective vibration attenuation effect in the frequency bands of 43 Hz - 55 Hz and 73 Hz - 156 Hz, and the maximum vibration attenuation can reach 60 dB. The calculation shows that the metamaterial pipeline vibration absorber can effectively control the vibration of the square pipeline structure in the low-frequency band below 200 Hz. In addition, except for the vibration within the bandgap frequency band being effectively suppressed, the resonance peaks of the pipeline vibration are effectively attenuated.

[0068] The calculation results of the third embodiment show that the metamaterial pipeline vibration absorber proposed by the present invention can show an effective vibration suppression characteristic for various pipeline configurations applied in engineering practice. Compared with the circular pipeline applied in the first embodiment, the metamaterial pipeline vibration absorber also achieves a good vibration reduction effect on the square pipeline. This shows that the metamaterial pipeline vibration absorber has good versatility for pipelines in engineering applications and has high engineering application value.

[0069] Matters not covered by the present invention are well-known technologies.

[0070] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0071] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the appended claims.

[0072] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A structure of a metamaterial pipeline vibration absorber with adjustable bandgap, characterized in that, Comprising: A main oscillator module, which is used to be installed on the outer wall of the metamaterial pipeline matrix (100), generate a local resonance band gap based on the local resonance effect of the metamaterial, suppress the transmission of elastic waves in the pipeline, and achieve effective control of low-frequency vibration; An additional oscillator module, which is arranged on the main oscillator module in an axially slidable and adjustable manner along the metamaterial pipeline matrix (100) to achieve adjustable and precise control of the vibration suppression frequency band of the metamaterial pipeline; Through the synergistic effect of the main oscillator module and the additional oscillator module, low-frequency vibration suppression of the metamaterial pipeline is achieved.

2. The structure of the metamaterial pipe vibration absorber with adjustable bandgap according to claim 1, characterized in that The main oscillator module includes an elastic bearing ring (200) and a mass ring (300). An elastic bearing ring (200) is provided at each end of the mass ring (300), and both ends of the mass ring (300) are fixed on the outer wall of the metamaterial pipeline matrix (100) through the elastic bearing ring (200); The inner wall surface of the mass ring (300) is attached to the outer wall surface of the elastic bearing ring (200), and the mass ring (300) is fixedly connected to the elastic bearing ring (200).

3. The structure of the metamaterial pipeline vibration absorber with adjustable bandgap according to claim 2, characterized in that, The mass ring (300) is formed by relatively buckling and connecting two half-ring units.

4. The structure of the metamaterial pipeline vibration absorber with adjustable bandgap according to claim 2, characterized in that, The additional oscillator module is arranged on the mass ring (300) via a sliding module; The sliding module includes a slide rail (400), a connecting clamping ring (500), and a locking member (600). The slide rail (400) is arranged on the outer wall surface of the mass ring (300) along the axial direction of the mass ring (300), and multiple slide rails (400) are arranged at equal intervals along the circumferential direction of the mass ring (300); The connecting clamping ring (500) is arranged around the mass ring (300) along the circumferential direction of the mass ring (300) and is fixedly connected to the additional oscillator module. The connecting clamping ring (500) and the additional oscillator module are jointly slidably connected to the slide rail (400). The locking member (600) is arranged along the radial direction of the mass ring (300), and by rotating the locking member (600), the connecting clamping ring (500) and / or the additional oscillator module is locked on the mass ring (300).

5. The structure of the metamaterial pipeline vibration absorber with adjustable bandgap according to claim 4, characterized in that Two connecting clamping rings (500) are respectively located at both ends of the mass ring (300) and are arranged oppositely. A synchronous driving mechanism is provided between the two connecting clamping rings (500), and the two connecting clamping rings (500) are driven to slide synchronously closer or slide synchronously away through the synchronous driving mechanism.

6. The structure of the metamaterial pipeline vibration absorber with adjustable bandgap according to claim 5, characterized in that, The synchronous driving mechanism includes a mounting boss (700), a gear (800), and a rack (900); The mounting boss (700) is arranged on the outer wall surface of the mass ring (300) and is located at the central position between the two connecting clamping rings (500). The gear (800) is rotatably arranged on the mounting boss (700). A rack (900) arranged along the axial direction is provided on each connecting clamping ring (500) and the rack (900) faces the mounting boss (700). The racks (900) of the two connecting clamping rings (500) are meshed with each other on the gear (800) and the non-toothed sides of the racks (900) are limited by the mounting boss (700); By driving the gear (800) to rotate to drive the axial movement of the rack (900), the two connecting clamping rings (500) are further driven to slide synchronously closer or slide synchronously away.

7. The structure of the metamaterial pipeline vibration absorber with adjustable bandgap according to any one of claims 4 to 6, characterized in that The additional oscillator module includes a plurality of cantilever units, which are arranged on the connecting snap ring (500) along the axial direction of the connecting snap ring (500), and the cantilever ends are arranged on the side away from the mass ring (300), and the plurality of cantilever units are arranged at equal intervals along the circumferential direction of the connecting snap ring (500).

8. The structure of the metamaterial pipeline vibration absorber with adjustable bandgap according to claim 7, characterized in that, The cantilever units on the two connecting snap rings (500) are arranged in one-to-one correspondence; or the cantilever units on the two connecting snap rings (500) are arranged relatively offset; or the number of cantilever units on the two connecting snap rings (500) is the same; or the number of cantilever units on the two connecting snap rings (500) is different.

9. The structure of the metamaterial pipeline vibration absorber with adjustable bandgap according to claim 8, characterized in that, The cantilever unit includes a cantilever beam (1000) and a tip mass (1100), the tip mass (1100) is located at the cantilever end of the cantilever beam (1000), and the connecting end of the cantilever beam (1000) is slidably connected with the slide rail (400) and fixedly connected with the corresponding connecting snap ring (500).

10. The structure of the metamaterial pipeline vibration absorber with adjustable bandgap according to claim 9, characterized in that, The cantilever beam (1000) and / or the tip mass (1100) is a metal material part; and / or the mass ring (300) is a metal material part, and the elastic bearing ring (200) is a viscoelastic material part.

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