Pipe vibration absorber with linear-nonlinear characteristics and design method thereof

Abstract

The present application relates to a kind of pipeline vibration absorber with linear-nonlinear characteristics and its design method, wherein, pipeline vibration absorber includes: shell and resonance component;The side surface of shell is the circular arc surface that is attached to the surface of pipeline, and circular arc mounting cavity coaxial with circular arc surface is arranged in shell;Resonance component is installed in circular arc mounting cavity, for presenting linear stiffness or equivalent nonlinear stiffness in vibration state;Resonance component includes: vibrator unit and damping element;Vibrator unit is arranged in circular arc mounting cavity with shell connection, and vibrator unit presents linear stiffness of resonance component with linear characteristics in vibration state based on the connecting structure between shell;Damping element is covered on vibrator unit, and when vibrator unit is in vibration state, damping element is used to present as nonlinear characteristics when physical coupling occurs between vibrator unit and shell, and the equivalent nonlinear stiffness of resonance component is obtained.

Description

Technical Field

[0001] This invention relates to the field of vibration control technology, and in particular to a pipeline vibration absorber with linear-nonlinear characteristics and its design method. Background Technology

[0002] In modern high-end equipment and precision industrial systems, pipelines play a crucial role in transporting fluids and transferring energy, and their dynamic stability is decisive for the safety and efficiency of the entire system. Take, for example, the fuel lines of aircraft engines and the cooling lines of ship propulsion systems, which are constantly exposed to complex, wide-frequency vibration environments. These vibrations originate from various excitation sources; the rotation and friction of components during mechanical operation can induce vibrations, and the pulsation of fluid flowing within the pipelines can also contribute to vibration.

[0003] This broadband vibration poses a significant threat to piping systems. It easily causes fatigue damage, reduces pipeline lifespan, and increases the risk of failure. Vibrations can lead to leaks at connections, causing fluid interruptions or energy transfer obstructions, affecting normal system operation. For instruments and equipment reliant on piping systems, vibration can also cause abnormal readings, preventing operators from obtaining accurate information and impacting overall system control and decision-making. More seriously, vibration can trigger system resonance. Once resonance occurs, the vibration amplitude increases dramatically, posing a serious threat to the reliable operation of equipment and potentially causing system damage and failure. Therefore, developing highly adaptable and effective broadband vibration reduction technology for pipelines is crucial for improving the overall performance of high-end equipment and has become a critical issue that urgently needs to be addressed in this field.

[0004] Traditional pipeline vibration control methods mainly include the use of linear vibration isolation bearings, viscoelastic damping layers, or tuned dynamic vibration absorbers. These methods are all based on linear vibration theory and, while capable of controlling vibration to some extent, have significant limitations. Their effective operating frequency bands are typically narrow, only achieving good vibration reduction within a specific frequency range. For low-frequency vibrations, the suppression effect of these traditional methods is very limited, making it difficult to meet practical needs. Moreover, in engineering practice, high-end equipment often has strict lightweight requirements, and space is also subject to many constraints. Under these circumstances, traditional methods struggle to achieve stable, wide-bandwidth vibration reduction while meeting lightweight and space constraints.

[0005] The emergence of metamaterials has brought entirely new ideas to the field of vibration control. Metamaterials are materials made from artificially designed periodic or aperiodic microstructures. Thanks to this unique structure, they can remarkably control the propagation of elastic waves, exhibiting bandgap characteristics not found in traditional materials. Among them, linear mechanical metamaterials based on the principle of local resonance can form elastic wave bandgaps within a specific frequency range, preventing elastic waves from propagating within that frequency range, thereby achieving vibration reduction. However, the bandwidth and center frequency of a linear bandgap are entirely determined by the inherent parameters of the structure. Once designed, it is difficult to flexibly adjust to changes in the actual vibration environment, making it unsuitable for complex and variable broadband vibration environments. This inherent characteristic greatly limits the engineering application prospects of linear metamaterials when facing complex broadband excitations.

[0006] Nonlinear metamaterials, as an important branch of metamaterials, refer to mechanical metamaterials with nonlinear dynamic properties. Research has found that introducing controllable nonlinear factors into metamaterial design can overcome the limitations of linear systems. Through nonlinear mechanisms, vibrational energy can be transferred and dissipated between different modes and frequencies, thereby achieving vibration suppression over a wider frequency band. This brings new hope for solving broadband vibration reduction problems in pipelines. However, transforming nonlinear metamaterial theory into practical vibration-absorbing devices suitable for pipelines is not easy and still faces many challenges. Currently, most nonlinear designs are still only at the theoretical simulation stage or based on simplified experimental models, which are far from practical engineering applications. Moreover, the environmental robustness, long-term stability, and manufacturability of these designs have not been fully verified. Their vibration reduction effect and stability may be affected under different environmental conditions, and they may also face many difficulties in actual manufacturing. In addition, there is currently a lack of systematic design methods, making it impossible to simultaneously meet multiple engineering requirements such as broadband, omnidirectional, lightweight, and reliable performance.

[0007] Therefore, there is an urgent need for a new solution for pipeline vibration control that can comprehensively address a series of challenges, including broadband vibration suppression, omnidirectional adaptation, nonlinear stability, and engineering-feasible manufacturing. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a pipeline vibration absorber with linear-nonlinear characteristics and its design method.

[0009] To achieve the above-mentioned objectives, the present invention provides a pipeline vibration absorber with linear-nonlinear characteristics, comprising: a housing and a resonant assembly;

[0010] One side of the outer casing is an arc surface that fits against the surface of the pipeline, and an arc mounting cavity coaxial with the arc surface is provided in the outer casing. The resonant component is installed in the arc mounting cavity to exhibit linear stiffness or equivalent nonlinear stiffness under vibration. The resonant assembly includes: an oscillator unit and a damping element; The oscillator unit is connected to the outer shell and arranged in an arc mounting cavity. When the oscillator unit is in a vibrating state, it exhibits linear stiffness with linear characteristics of the resonant component based on the connection structure between it and the outer shell. The damping element is wrapped around the circumferential side of the oscillator unit. When the oscillator unit is in a vibrating state, the damping element is used to make the interaction force exhibit a smooth nonlinear characteristic when the oscillator unit and the outer shell are physically coupled, so as to obtain the equivalent nonlinear stiffness of the resonant component.

[0011] According to one aspect of the invention, in a non-vibration state, the damping element has a gap between it and the inner surface of the arc-shaped mounting cavity.

[0012] According to one aspect of the invention, a plurality of resonant components are arranged along the circumference of the arc mounting cavity, and the plurality of resonant components are spaced apart.

[0013] According to one aspect of the invention, the structures of the plurality of said resonant components are identical.

[0014] According to one aspect of the invention, the oscillator unit comprises: an oscillator and an elastic element; The elastic element is a columnar elastic body that is equivalent to a spring; One end of the elastic element is fixedly connected to the vibrator along its axial direction, and the other end is fixedly connected to the side wall of the arc-shaped mounting cavity.

[0015] According to one aspect of the invention, the oscillator is provided with a connection channel; The axis of the connecting channel is aligned with the axis of the oscillator, and the end of the elastic element is embedded in the connecting channel and fixedly connected to the oscillator.

[0016] According to one aspect of the invention, the elastic element is fixed to the connecting channel by an interference fit or adhesive bonding.

[0017] According to one aspect of the invention, the elastic element is a cylindrical elastomer made of aluminum alloy.

[0018] According to one aspect of the invention, the oscillator is a quarter-circular arc-shaped block made of steel.

[0019] To achieve the above-mentioned objective, this invention provides a design method for the aforementioned pipeline vibration absorber with linear-nonlinear characteristics, comprising the following steps: S1. Determine the range of vibration frequencies that need to be suppressed based on the dynamic characteristics of the target pipeline; S2. Based on the vibration frequency range and the mass constraint of the pipeline vibration absorber with linear-nonlinear characteristics attached to the target pipeline, the mass of the oscillator in the oscillator unit and the linear stiffness coefficient and equivalent nonlinear stiffness coefficient of the resonant component (2) are determined. S3. Based on the obtained linear stiffness coefficient and equivalent nonlinear stiffness coefficient, and the pipe size of the target pipe, determine the structural parameters of the pipe vibration absorber. The structural parameters include: the size of the elastic element, the distance between the arc mounting cavity of the outer shell and the oscillator, the material, size and covering method of the damping element, and the size of the outer shell. S4. Based on the structural parameters, complete the processing and assembly of the outer shell, oscillator, elastic element and damping element, and complete the design of the pipeline vibration absorber.

[0020] According to one aspect of the present invention, this solution effectively solves the drawbacks of pipeline vibration-absorbing materials, which are difficult to simultaneously achieve multi-directional vibration suppression, wide-range vibration reduction at the same frequency, and miniaturization of the structure.

[0021] According to one aspect of the present invention, the oscillator unit is designed based on a spatially symmetric topology, achieving synchronous suppression of all radial vibrations in the pipeline. Furthermore, this approach effectively utilizes the strong nonlinear effect generated by the physical collisions of the oscillator to construct corresponding metamaterial cells (i.e., resonant components). These metamaterial cells can switch between linear and nonlinear characteristics based on the external vibration amplitude, generating linear / nonlinear local resonant band gaps, thus producing excellent broadband vibration reduction for the pipeline.

[0022] According to one aspect of the present invention, this approach features miniaturization, integration, and high reliability. When applied to vibration and noise control and various pipeline vibration reduction applications, it exhibits higher strength and stability, achieving low-frequency, broadband, and efficient vibration suppression effects with minimal added mass.

[0023] According to one aspect of the present invention, the oscillator unit can flexibly adjust the linear stiffness of the structure by controlling the radius, length, material, and other conditions of the elastic element; the nonlinear stiffness coefficient can be controlled by controlling the distance between the oscillator and the outer shell, the thickness of the damping element, the material of the damping element, the material of the oscillator, and the material of the outer shell; the position of the local resonance bandgap can be controlled by adjusting the linear stiffness of the structure and the mass of the oscillator; and the damping coefficient can be adjusted by controlling the material of the damping element, thereby controlling the energy absorption efficiency.

[0024] According to one aspect of the present invention, this solution introduces a strong nonlinear vibration reduction mechanism based on the coupling effect of oscillator resonance and physical field collision into the pipeline vibration absorption structure, achieving the characteristic of linear-nonlinear dual-mode conversion. When the external excitation frequency is close to the natural frequency of the oscillator, the oscillator resonates, generating a large amplitude motion, and then collides with the shell or another symmetrically arranged oscillator within a preset gap, exciting the system to generate a strong nonlinear dynamic response, thereby significantly widening the operating frequency band of the vibration absorber and improving its energy absorption capacity. Simultaneously, during the collision process, efficient energy dissipation is achieved through damping elements set on the outside of the oscillator, converting mechanical energy into other forms of energy dissipation, further improving vibration reduction efficiency and operational stability. In addition, omnidirectional vibration reduction of the pipeline is achieved through the symmetrical design of the topology. Compared with traditional vibration absorption structures that rely on linear tuning, the present invention can still maintain excellent vibration reduction performance under frequency changes and complex operating conditions of the pipeline system, and has advantages such as compact structure and convenient installation, and is particularly suitable for broadband vibration suppression of pipeline systems.

[0025] According to one aspect of the present invention, this solution can be directly installed on the outer wall of various pipelines to achieve low-frequency, broadband, and efficient vibration suppression effects with minimal added mass, making it particularly suitable for complex vibration scenarios such as aerospace, shipbuilding, and industrial pipelines.

[0026] According to one aspect of the present invention, the damping element can effectively buffer the direct rigid impact of the oscillator, making the interaction force exhibit a smoother nonlinear characteristic; moreover, by utilizing its viscoelastic properties, it introduces an additional damping effect into the system; furthermore, based on the damping element, it also significantly reduces or even eliminates the noise radiation generated by metal collisions, thereby effectively reducing acoustic interference during operation. Attached Figure Description

[0027] Figure 1 This is a structural diagram of the pipeline vibration absorber with linear-nonlinear characteristics according to the present invention; Figure 2 This is a structural diagram of the oscillator unit of the present invention; Figure 3 This is a structural diagram of the oscillator of the present invention; Figure 4 This is a structural diagram of the columnar elastomer of the present invention; Figure 5 The diagram shows the restoring force curve generated by the pipeline vibration absorber with linear-nonlinear characteristics under vibration conditions according to the present invention. Figure 6 This diagram illustrates the influence of the parameters of the pipeline vibration absorber with linear-nonlinear characteristics of the present invention on the vibration characteristics of the system. Figure 6 (a) shows the effect of changing the resonant frequency of the resonant component on the vibration characteristics of the system. Figure 6(a) shows the effect of changing the damping loss factor of the resonant component on the vibration characteristics of the system. Figure 6 (c) shows the effect of changing the equivalent nonlinear stiffness coefficient of the resonant component on the vibration characteristics of the system; Figure 7 This is a schematic diagram illustrating the arrangement, installation, and testing of mechanical metamaterial pipe structures for two types of pipe vibration absorbers with linear-nonlinear characteristics, as described in an embodiment of the present invention. Figure 7 (a) is a schematic diagram of the layout, installation, and testing of a linear mechanical metamaterial pipeline structure for a pipeline vibration absorber with linear-nonlinear characteristics. Figure 7 (b) is a schematic diagram of the nonlinear mechanical metamaterial pipeline structure layout, installation and testing of a pipeline vibration absorber with linear-nonlinear characteristics; Figure 8 This is a vibration experiment result diagram of a linear mechanical metamaterial pipe structure with linear-nonlinear characteristics, as shown in the embodiment of the present invention. Figure 8 (a) is a schematic diagram of the transient response based on velocity-time at an excitation frequency of 525Hz. Figure 8 (b) is a schematic diagram of frequency domain vibration transmission characteristics based on transmissivity-frequency in the frequency sweep range of 1-1000Hz. Figure 9 This is a characteristic diagram of the omnidirectional vibration reduction of a linear mechanical metamaterial pipeline structure with linear-nonlinear characteristics, as shown in an embodiment of the present invention. Figure 10 The figure shows the vibration test results of the nonlinear mechanical metamaterial pipeline structure and pipeline matrix of the pipeline vibration absorber with linear-nonlinear characteristics in an embodiment of the present invention. Figure 10 (a) shows the vibration results of the pipeline substrate based on velocity-frequency under different excitations. Figure 10 (b) Vibration results of nonlinear mechanical metamaterial pipeline structures based on velocity-frequency under different excitations; Figure 11 This is a schematic diagram of the frequency domain vibration transmission characteristics of a nonlinear mechanical metamaterial pipeline structure in the frequency sweep range of 1-1000Hz, based on the transmissivity-frequency. Detailed Implementation

[0028] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the embodiments will be described in detail below.

[0029] In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" express orientations or positional relationships based on the orientations or positional relationships shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on the present invention.

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the embodiments of the present invention are not limited to the following embodiments.

[0031] like Figure 1As shown, according to one embodiment of the present invention, a pipeline vibration absorber with linear-nonlinear characteristics includes: a housing 1 and a resonant component 2; wherein, one side of the housing 1 is an arc surface that fits against the pipeline surface, and an arc mounting cavity 11 coaxial with the arc surface is provided in the housing 1; wherein, by setting one side of the housing 1 as an arc surface that fits against the pipeline surface, the pipeline vibration absorber can be tightly and seamlessly fitted to the pipeline surface, which is more beneficial to improving structural stability and mechanical coupling efficiency. In this embodiment, the resonant component 2 is installed in the arc mounting cavity 11, thereby, by installing the housing 1 based on the matching of its outer arc surface with the pipeline surface, the resonant component 2 can achieve a corresponding regular distribution on the outer periphery of the pipeline to achieve excellent vibration absorption performance. Furthermore, to facilitate the installation of the pipeline vibration absorber and the pipeline, fixed connecting ears 1a can be provided at both ends of the housing 1, and through holes connected by I-connections are provided on the fixed connecting ears 1a to facilitate locking after threaded connectors pass through. In this embodiment, the installation direction of the fixed connecting ears 1a provided at both ends of the outer casing 1 is determined based on the installation method of the outer casing 1 and the pipeline. When one pipeline vibration absorber can cover half of the outer circumference of the pipeline, the two fixed connecting ears 1a can be set symmetrically and flush. Thus, two pipeline vibration absorbers can be symmetrically installed on both sides of the pipeline, so that the fixed connecting ears 1a of the two pipeline vibration absorbers are aligned with each other, and the fixed installation on the pipeline can be achieved by locking the threaded connector through the through hole on the fixed connecting ear 1a. Of course, when the pipeline vibration absorber can cover 1 / 4 of the outer circumference of the pipeline, the two fixed connecting ears 1a can be set symmetrically and perpendicular to each other. Thus, four pipeline vibration absorbers can be distributed sequentially on the outer circumference of the pipeline, with the fixed connecting ears 1a of adjacent pipeline vibration absorbers aligned with each other, and the fixed installation on the pipeline can be achieved by locking the threaded connector through the through hole on the fixed connecting ear 1a. In addition, if only one pipe vibration absorber needs to be installed on the outside of the pipe, the installation can be achieved by combining the pipe vibration absorber with a clamp.

[0032] In this embodiment, the resonant component 2 is the main structural component in the pipeline vibration absorber that realizes vibration absorption, and is used to exhibit linear stiffness or equivalent nonlinear stiffness under vibration. It includes: oscillator unit 21 and damping element 22. Specifically, the oscillator unit 21 is arranged in the arc mounting cavity 11 connected to the outer shell 1, and when the oscillator unit 21 is under vibration, it exhibits linear stiffness with linear characteristics based on the connection structure between it and the outer shell 1. In this embodiment, the oscillator unit 21 is a regular block with a fan-shaped annular cross section. Of course, in different embodiments, the oscillator unit 21 can also be set as a regular column with a circular cross section.

[0033] Furthermore, the damping element 22 covers the circumferential side surface of the oscillator unit 21. When the oscillator unit 21 is in a vibrating state, the damping element 22 is used to make the interaction force exhibit a smooth nonlinear characteristic when the oscillator unit 21 and the outer shell 1 are physically coupled, so as to obtain the equivalent nonlinear stiffness of the resonant component 2. The damping element 22 is made of polymer damping materials such as rubber and fiber cloth, and its thickness and material properties can be selected according to the actual vibration reduction requirements and nonlinear characteristics. When the oscillator unit 21 vibrates and comes into contact with or is compressed by the outer shell 1, the damping element 22 undergoes compression, shearing or friction deformation, thereby dissipating vibration energy.

[0034] In this embodiment, to facilitate the installation of the oscillator unit 21 and to easily suppress pipeline vibration, one end of the oscillator unit 21 is connected to the outer shell 1 along the axial direction of the arc mounting cavity 11. This allows for easier sensing of the pipeline's vibration state on the circumferential outer side, thereby enabling the resonant component 2 to exhibit linear stiffness or equivalent nonlinear stiffness based on different vibration amplitudes under vibration conditions. Furthermore, the axial connection of the oscillator unit 21 to the outer shell 1 provides greater flexibility in vibration adaptation in both the pipeline's axial and circumferential directions, effectively... By avoiding the limitations imposed by the connection structure, the oscillator unit 21 exhibits linear stiffness or equivalent nonlinear stiffness characteristics depending on the input magnitude during motion. Specifically, when the oscillator unit 21 vibrates and the damping element 22 does not contact the outer shell 1, the linear stiffness is provided solely by the connection structure between the oscillator unit 21 and the outer shell 1. However, when the vibration amplitude of the oscillator unit 21 is large enough to cause the damping element 22 to contact the outer shell 1, the nonlinear characteristics of the covered damping element 22 itself smooth out the stiffness of the contact collision, thus achieving superior vibration absorption performance.

[0035] like Figure 1As shown, according to one embodiment of the present invention, in the non-vibration state, the damping element 22 of the oscillator unit 21 has a gap between itself and the inner surface of the arc mounting cavity 11. In this embodiment, the damping element 22 covering the outside of the oscillator unit 21 has a gap with the inner surface of the arc mounting cavity 11 along both the radial and circumferential directions. Therefore, based on this gap, the vibration absorption effect exhibited by the oscillator unit 21 can show different responses. When the amplitude of the oscillator unit 21 is small and does not reach the width of the gap, the oscillator unit 21 mainly exhibits linear vibration absorption characteristics based on the connection structure between its axial end and the outer shell 1. When the amplitude is large enough to reach or even exceed the width of the gap, the oscillator unit 21 exhibits a combination of linear and nonlinear vibration absorption based on the combination of the connection structure between its axial end and the outer shell 1 and the externally covered damping element 22. In particular, the flexible damping effect of the damping element 22 itself and the impact friction at the corresponding position make the nonlinear characteristics smoother, resulting in superior combined vibration absorption performance. Therefore, based on the gap between the damping element 22 and the inner surface of the arc mounting cavity 11, the vibration absorption performance of this scheme can be effectively controlled, and segmented adaptation to different vibration intensities can be achieved. Then, the corresponding gap can be designed for specific working conditions, making the performance of this scheme more beneficial, and having better control over the strength of nonlinear stiffness.

[0036] like Figure 1 As shown, according to one embodiment of the present invention, multiple resonant components 2 are arranged along the circumference of the arc mounting cavity 11, and the multiple resonant components 2 are spaced apart. In this embodiment, two resonant components 2 can be set and symmetrically distributed in the arc mounting cavity 11 to ensure that the solution has more uniform vibration absorption performance. Furthermore, in order to ensure the uniformity of vibration absorption performance of multiple resonant components 2, the structure of multiple resonant components 2 is set to be consistent, which effectively ensures the uniformity of mass distribution on the entire pipeline vibration absorber. Of course, three, four, etc., resonant components 2 can also be set, which can be determined according to the specific structural design, and will not be elaborated here.

[0037] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, according to one embodiment of the present invention, the oscillator unit 21 includes an oscillator 211 and an elastic element 212. In this embodiment, the oscillator 211 is a steel arc-shaped (i.e., fan-shaped cross-section) block, which can be set as a 1 / 4 arc shape as needed, or other segmented arc shapes can be used, specifically determined based on the size range of the arc mounting cavity 11 and the number of oscillators 211, which will not be elaborated here. In another embodiment, when the oscillator unit 21 is set as a cylinder, the oscillator 211 can also be set as a cylinder. Further, the elastic element 212 is a columnar elastic body equivalent to a spring, such as... Figure 4 As shown; one end of the elastic element 212 is fixedly connected to the oscillator 211 in the axial direction, and the other end is fixedly connected to the side wall of the arc mounting cavity 11. Thus, the oscillator 211 has the degree of freedom to reciprocate relative to the outer shell 1 in the pipeline direction, so as to generate a significant vibration response under external excitation and exchange energy with the pipeline vibration. In addition, since the oscillator 211 is coaxial with the pipeline, especially in a symmetrical manner, when it is installed in the circumferential direction of the pipeline, the vibration reduction effect in the 360-degree radial direction of the pipeline is approximately the same, ensuring the isotropic effect.

[0038] In this embodiment, the elastic element 212 not only connects the oscillator 211 to the outer casing 1, but also provides a restoring force when the oscillator 211 is displaced. Furthermore, the elastic element 212 is a cylinder made of aluminum alloy, designed to exhibit perfectly linear stiffness during the movement of the oscillator 211 (i.e., generating a perfectly linear restoring force related to displacement). When the damping element 22 comes into contact with the outer casing 1, the stiffness of the entire elastic element 212 is composed of the linear characteristics of the elastic element 212 and the nonlinear characteristics of the damping element 22, forming an equivalent nonlinear stiffness. This allows the entire resonant assembly 2 to have different dynamic responses under different excitation amplitude conditions, thereby enabling the pipeline vibration absorber to have a lower vibration level over a wider frequency band.

[0039] In another embodiment, multiple damping rubber rings can be selectively fitted at intervals on the outer surface of the elastic element 212. When the swing amplitude of the oscillator 211 is small, the elastic element 212 body exhibits linear stiffness to provide restoring force. However, when the swing amplitude is large (such as when the damping element 22 comes into contact with the outer shell 1), the intervals between the rubber rings are eliminated due to the deformation of the elastic element 212, resulting in nonlinear damping during contact. This achieves a synergistic effect with the damping element 22, making the vibration reduction performance of the entire resonant assembly 2 more beneficial. In this embodiment, the intervals between the damping rubber rings can be flexibly set according to actual needs to adjust the timing of the damping rubber rings' intervention during the vibration reduction process, making this solution more flexible in use.

[0040] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, the oscillator 211 is provided with a connecting channel 211a; wherein, the axis of the connecting channel 211a is aligned with the axis of the oscillator 211, and the end of the elastic element 212 is embedded in the connecting channel 211a and fixedly connected to the oscillator 211. In this embodiment, the elastic element 212 is fixed to the connecting channel 211a by an interference fit or adhesive bonding. The other end of the elastic element 212 is fixedly connected to the outer shell 1 by welding; in this embodiment, to facilitate the fixed connection of the elastic element 212, one end of the arc mounting cavity 11 is closed, and a mounting through hole is provided at the closed end of the arc mounting cavity 11. The elastic element 212 is inserted into the mounting through hole and then welded to ensure reliable installation and positioning and a firm and stable weld.

[0041] The working principle of the pipeline vibration absorber with linear-nonlinear characteristics in this scheme is as follows: It is stably fitted onto the outside of the corresponding pipeline using threaded fasteners. When the pipeline vibrates due to fluid pulsation, mechanical excitation, or external disturbance, the vibration is transmitted through the outer shell 1 to the oscillator 211. When the external excitation frequency approaches or enters the resonant frequency range of the oscillator unit 211, the oscillator 211 generates a large vibration response. When the amplitude reaches a preset threshold, the oscillator 211 will collide with the inner wall of the outer shell 1 or another oscillator 211, thereby introducing a strongly nonlinear dynamic process based on the damping element 22. This collision process breaks the limitation of traditional linear vibration absorbers that only work effectively near a single tuning frequency, enabling the system to produce significant energy transfer and dissipation effects over a wider frequency range.

[0042] According to one embodiment of the present invention, the pipe vibration absorbers of this solution can be arranged in an array along the corresponding pipe extension direction according to actual vibration absorption needs, or distributed in a non-array manner according to actual installation position constraints, or each pipe vibration absorber can be installed at a location where the pipe structure vibrates significantly and requires vibration reduction and shock resistance (non-array is possible), or the pipe vibration absorbers can be installed close to the pulsation source. The layout of the pipe vibration absorbers in this solution can adapt to changes in the pipe bending direction, that is, it does not require straight pipes and can be bent pipes.

[0043] According to one embodiment of the present invention, the present invention provides a design method for the aforementioned pipeline vibration absorber with linear-nonlinear characteristics, comprising the following steps: S1. Determine the range of vibration frequencies that need to be suppressed based on the dynamic characteristics of the target pipeline; S2. Based on the vibration frequency range and the mass constraint of the pipeline vibration absorber added to the target pipeline, the mass of the oscillator 211 in the oscillator unit 21 and the linear stiffness coefficient and equivalent nonlinear stiffness coefficient of the resonant component 2 are determined. S3. Based on the obtained linear stiffness coefficient and equivalent nonlinear stiffness coefficient, and the pipe size of the target pipe, determine the structural parameters of the pipe vibration absorber. The structural parameters include: the size of the elastic element 212, the distance between the arc mounting cavity 11 of the outer shell 1 and the oscillator 211 and the oscillator, the material, size and covering method of the damping element 22, and the size of the outer shell 1. S4. Based on the structural parameters, complete the processing and assembly of the outer shell 1, oscillator 211, elastic element 212 and damping element 22, and complete the design of the pipeline vibration absorber.

[0044] According to one embodiment of the present invention, in step S1, in the step of determining the vibration frequency range to be suppressed based on the dynamic characteristics of the target pipeline, the dynamic characteristics generated by the target pipeline are collected based on its actual working process. In this process, different working conditions (such as fluid pulsation in the pipeline, mechanical excitation or external disturbance) are changed to make the target pipeline exhibit corresponding dynamic characteristics, thereby accurately collecting its vibration frequency range.

[0045] According to one embodiment of the present invention, in step S2, based on the vibration frequency range and the mass constraint of the additional pipe vibration absorber on the target pipe, taking two pipe vibration absorbers symmetrically fixed on the pipe as an example, the local resonant bandgap of the two pipe vibration absorbers will be determined by the resonant frequency of the oscillator unit 21. f 0 is determined. To achieve low-frequency broadband vibration suppression, the resonant frequency is... f The design is at the excitation frequency.

[0046] Furthermore, for the two pipeline vibration absorbers, when the target pipeline is in a low-amplitude vibration state, the resonant component 2 mainly exhibits linear resonant vibration absorption behavior, which has a significant suppression effect on vibration in a specific frequency band. When the vibration amplitude of the target pipeline increases, the oscillator 211 enters the collision working state, introducing a strong nonlinear effect through the collision-damping energy dissipation mechanism, so that the vibration energy is efficiently dissipated over a wider frequency range, thereby achieving a wide-frequency and efficient vibration suppression effect. In this embodiment, once the vibration frequency range to be suppressed is determined, the linear resonant frequency of the two pipeline vibration absorbers... f 0 can also be determined at the resonant frequency. f Given that the structural dimensions and additional mass constraints of the pipeline vibration absorber are known, the mass of an oscillator 211 can also be determined. m Therefore, when the response amplitude of oscillator 211 is small, the dynamic behavior of resonant component 2 is close to the properties of a linear mechanical metamaterial, and the resonance frequency is...f 0 is:

[0047] in, This represents the linear stiffness of the resonant component 2 when it does not collide with the outer casing 1, and is also the linear stiffness of the elastic element 212.

[0048] Based on this, since the resonant frequency has already been determined... f 0 and the mass of oscillator 211 m Then the linear stiffness of resonant component 2 can be calculated. (Also the linear stiffness of elastic element 212).

[0049] Furthermore, based on the pipeline vibration absorber of this scheme, during operation, the resonant component 2 exists in both contact and non-contact states, thus the restoring force experienced by the resonant component 2 during vibration... F ( x With the relative displacement of oscillator 211 x The pattern of change is a piecewise function, and it is expressed as:

[0050] in, This indicates the gap between the damping element 22 and the inner surface of the arc-shaped mounting cavity 11. Indicates linear restoring force. Indicates contact stiffness, This represents the power law of contact forces, and .

[0051] In this embodiment, the gap The size of the component significantly affects the performance characteristics of the resonant component 2. When the excitation is large, the resonant component 2 is less likely to collide with the outer shell 1, exhibiting a linear characteristic; similarly, when the excitation is small, the resonant component 2 is also less likely to collide with the outer shell 1, exhibiting a linear characteristic. Therefore, appropriate gaps should be designed according to specific operating conditions. This allows for segmented vibration absorption performance, and further, the vibration can be controlled through the set gaps. It significantly affects the strength of nonlinear stiffness.

[0052] like Figure 5 As shown, based on restoring force F ( x The piecewise function of ) can yield the corresponding restoring force curve, which is a nonlinear restoring force curve. F ( x It exhibits a strongly nonlinear function. When At that time, the corresponding physical process is that the resonant component 2 collides with the outer shell 1, causing the restoring force to... F ( x A sudden jump occurs; this strongly nonlinear force can be approximated by... It is expressed in the form of, where, and These represent the fitted linear stiffness coefficient and the equivalent nonlinear stiffness coefficient, respectively, from which the linear stiffness coefficient and the equivalent nonlinear stiffness coefficient of the resonant component 2 can be obtained.

[0053] like Figure 6 As shown, in this embodiment, changing the resonant frequency of the resonant component changes the effective range of the local resonant bandgap; changing the damping loss factor of the resonant component leads to a wider effective range of the local resonant bandgap as the damping increases, but it affects the vibration reduction effect; the introduction of the nonlinear characteristics of the damping element 22 generates a nonlinear local resonant bandgap. By changing the equivalent nonlinear stiffness coefficient of the resonant component, the effective range is significantly widened compared to the linear bandgap as the equivalent nonlinear stiffness coefficient increases, and the high-frequency vibration peak value is reduced.

[0054] According to one embodiment of the present invention, in step S3, since the corresponding linear stiffness coefficient and equivalent nonlinear stiffness coefficient have already been determined in the preceding steps, the corresponding restoring force is... F ( x The variation law of the target pipeline can be confirmed. Then, based on the fact that the pipeline size can be directly measured, the structural parameters of the entire pipeline vibration absorber can be selected based on the corresponding parameters determined in the previous steps to meet its corresponding linear stiffness coefficient and equivalent nonlinear stiffness coefficient. This will not be elaborated further here.

[0055] To further illustrate this plan, further examples will be provided.

[0056] Example A vibrator is used to induce vibration in a pipe vibration absorber with linear-nonlinear characteristics. The velocity signal of the resonant unit is measured using a laser vibrometer, and its natural frequency and nonlinear characteristics are then analyzed. In this example, the resonant frequency of the pipe vibration absorber is... f 0 = 500Hz.

[0057] like Figure 7As shown in (a), a linear mechanical metamaterial pipeline structure with pipeline vibration absorbers is constructed on a finite-sized pipeline structure by periodically arranging the aforementioned pipeline vibration absorbers. Taking a one-dimensional linear mechanical metamaterial pipeline structure with attached support as an example, 6×2 of the aforementioned pipeline vibration absorbers are attached to the pipeline substrate. Along the extension direction of the pipeline substrate, the distance between adjacent pipeline vibration absorbers is 236 mm, and they are installed in the same orientation, thus forming a linear mechanical metamaterial pipeline structure. The average mass of a single attached oscillator 211 is... m r =6g. Outer diameter of the pipe base. d o =8mm, inner diameter d i =5mm, made of stainless steel, 2m in length, the distance between two supports is defined as the lattice constant, lattice constant a =236mm.

[0058] Next, vibration tests were conducted to examine the vibration transmission characteristics of the linear metamaterial pipeline structure under swept-frequency excitation, as well as its time-domain attenuation characteristics at the target frequency, verifying the effectiveness of the lightweight, low-frequency, broadband, omnidirectional pipeline vibration absorber design method. Sweeped-frequency excitation was applied to one side of the right end of the linear metamaterial pipeline structure, with the excitation amplitude controlled by a power amplifier. A laser vibrometer was used to test the vibration response near the excitation point and at the leftmost end of the pipeline.

[0059] The vibration response of the pipe matrix without additional pipe dampers was used as a reference value. The linear mechanical metamaterial pipe structure consisted of six pipe dampers arranged in three sets of periods on the pipe. The added mass ratio of the structure was 35%. The linear mechanical metamaterial pipe structure was subjected to single-frequency excitation with the same excitation amplitude. f The transient response and frequency domain vibration transmission characteristics under a sweep frequency signal (1-1000Hz) with the same excitation amplitude at 525Hz are as follows: Figure 8 (a) and Figure 8 As shown in (b), compared to the pipeline aggregate without additional pipeline dampers, the linear mechanical metamaterial pipeline structure with additional pipeline dampers exhibits a significant localized resonant bandgap in the 450-620 Hz range, with a peak attenuation of nearly 60 dB at 525 Hz. This is compared with single-frequency excitation. f The transient response at 525Hz showed an RMS velocity of 0.022700 m / s for the pipe substrate. The RMS velocity of the linear mechanical metamaterial pipe structure with the added pipe vibration absorber decreased to 0.000074 m / s, a reduction of 99.67%. The peak velocity also decreased from 0.032224 m / s to 0.000179 m / s, a reduction of 99.45%. This indicates that strong linear local resonance characteristics can be achieved under sweeping, small-amplitude excitation, realizing low-frequency broadband vibration reduction performance.

[0060] Furthermore, the omnidirectional vibration reduction characteristics of the rotational linear mechanical metamaterial pipeline structure were verified by changing the angle between the pipeline vibration absorber and the excitation direction, such as... Figure 9 As shown, the angle between the three types of pipeline vibration absorbers and the excitation direction can produce almost similar vibration reduction effects within the same frequency range.

[0061] To verify the nonlinear characteristics of the pipeline vibration absorber with linear-nonlinear properties, the velocity signal of the resonant unit was measured using a laser vibrometer. By changing the output of the power amplifier, the excitation displacement was altered, and the change in the nonlinear natural frequency with the excitation amplitude was analyzed. The frequency drift phenomenon of two resonant components 2 was measured as follows: Figure 10 (a) and Figure 10 As shown in (b), it can be seen that the natural frequency of the resonant component 2 will shift to a higher frequency as the excitation amplitude increases. This phenomenon is caused by the collision between the oscillator 211 and the outer shell 1 during the vibration process, resulting in strong nonlinear coupling.

[0062] like Figure 7 As shown in (b), a nonlinear mechanical metamaterial pipeline structure is constructed on a finite-sized pipeline structure by periodically arranging the aforementioned pipeline vibration absorbers. Taking a one-dimensional nonlinear mechanical metamaterial pipeline structure with attached support as an example, 3×2 of the aforementioned pipeline vibration absorbers are attached to the pipeline substrate. Along the extension direction of the pipeline substrate, the distance between adjacent pipeline vibration absorbers is 600 mm, and the pipeline vibration absorbers are oriented in the same direction, thus forming a nonlinear mechanical metamaterial pipeline structure. The average mass of a single attached oscillator is... m r =6g. Pipeline base outer diameter d o =8mm, inner diameter d i =5mm, made of stainless steel, 2m in length, the distance between two supports is defined as the lattice constant, lattice constant a =600mm.

[0063] Next, vibration tests were conducted to examine the vibration transmission characteristics of the linear metamaterial pipeline structure under swept-frequency excitation, verifying the effectiveness of the lightweight, low-frequency, broadband pipeline vibration absorber. Sweeped-frequency excitation was applied to the right end of the nonlinear metamaterial pipeline structure, with the excitation amplitude controlled by a power amplifier. A laser vibrometer was used to test the vibration response near the excitation point and at the leftmost end of the pipeline.

[0064] The vibration response of the pipe matrix without additional pipe dampers was used as a reference value. The nonlinear metamaterial pipe structure with supports and pipe dampers consisted of three groups of six pipe dampers arranged periodically on the pipe matrix. The added mass ratio of the structure was 15%. The frequency domain vibration transmission characteristics of the nonlinear metamaterial pipe structure under swept-frequency signals (1-1000Hz) with different excitation amplitudes are as follows: Figure 11 As shown. Figure 11 As shown, a local resonant bandgap of approximately 110 Hz (from 500 Hz to 610 Hz) was generated under low-amplitude excitation. When the excitation amplitude was increased, the resonant component 2 collided with the outer casing 1, exhibiting strong nonlinearity. The results show that the system's resonant peak value decreased, and the bandgap attenuation valley shifted to higher frequencies. Comparing the system's first four resonant peak values, the average reduction was 10 dB. Furthermore, the local resonant bandgap expanded from 110 Hz to 140 Hz (from 475 Hz to 615 Hz), representing an improvement of 27.3%. Additionally, in the frequency range above 500 Hz, the transmission rate decreased by an average of 9 dB compared to the pipe substrate.

[0065] The above description is merely an example of a specific solution of the present invention. For any devices and structures not described in detail herein, it should be understood that they are implemented using common devices and methods already available in the art.

[0066] The above description is merely one embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pipeline vibration absorber with linear-nonlinear characteristics, characterized in that, include: The outer shell (1) and the resonant assembly (2); One side of the outer shell (1) is an arc surface that fits against the surface of the pipeline, and an arc mounting cavity (11) coaxial with the arc surface is provided in the outer shell (1). The resonant component (2) is installed in the arc mounting cavity (11) to exhibit linear stiffness or equivalent nonlinear stiffness under vibration. The resonant component (2) includes: an oscillator unit (21) and a damping element (22); The oscillator unit (21) is connected to the outer shell (1) and arranged in the arc mounting cavity (11). When the oscillator unit (21) is in the vibration state, it exhibits the linear stiffness of the resonant component (2) with linear characteristics based on the connection structure between it and the outer shell (1). The damping element (22) is covered on the circumferential side of the oscillator unit (21), and when the oscillator unit (21) is in a vibrating state, the damping element (22) is used to make the interaction force exhibit a smooth nonlinear characteristic when the oscillator unit (21) and the outer shell (1) are physically coupled, so as to obtain the equivalent nonlinear stiffness of the resonant component (2).

2. The pipeline vibration absorber with linear-nonlinear characteristics according to claim 1, characterized in that, In the non-vibration state, the damping element (22) of the oscillator unit (21) has a gap between the inner surface of the arc mounting cavity (11).

3. The pipeline vibration absorber with linear-nonlinear characteristics according to claim 1 or 2, characterized in that, Along the circumference of the arc mounting cavity (11), a plurality of resonant components (2) are arranged, and the plurality of resonant components (2) are spaced apart.

4. The pipeline vibration absorber with linear-nonlinear characteristics according to claim 3, characterized in that, The structures of the multiple resonant components (2) are identical.

5. The pipeline vibration absorber with linear-nonlinear characteristics according to claim 1, 2, or 4, characterized in that, The oscillator unit (21) includes: an oscillator (211) and an elastic element (212); The elastic element (212) is a columnar elastic body that is equivalent to a spring; One end of the elastic element (212) is fixedly connected to the vibrator (211) in the axial direction, and the other end is fixedly connected to the side wall of the arc mounting cavity (11).

6. The pipeline vibration absorber with linear-nonlinear characteristics according to claim 5, characterized in that, The oscillator (211) is provided with a connection channel (211a); The axis of the connecting channel (211a) is aligned with the axis of the oscillator (211), and the end of the elastic element (212) is embedded in the connecting channel (211a) and fixedly connected to the oscillator (211).

7. The pipeline vibration absorber with linear-nonlinear characteristics according to claim 6, characterized in that, The elastic element (212) is fixed to the connecting channel (211a) by means of interference fit or bonding.

8. The pipeline vibration absorber with linear-nonlinear characteristics according to claim 7, characterized in that, The elastic element (212) is a cylindrical elastomer made of aluminum alloy.

9. The pipeline vibration absorber with linear-nonlinear characteristics according to claim 8, characterized in that, The oscillator (211) is a 1 / 4 arc-shaped block made of steel.

10. A design method for a pipeline vibration absorber with linear-nonlinear characteristics as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Determine the range of vibration frequencies that need to be suppressed based on the dynamic characteristics of the target pipeline; S2. Based on the vibration frequency range and the mass constraint of the pipeline vibration absorber with linear-nonlinear characteristics attached to the target pipeline, the mass of the oscillator (211) in the oscillator unit (21) and the linear stiffness coefficient and equivalent nonlinear stiffness coefficient of the resonant component (2) are determined. S3. Based on the obtained linear stiffness coefficient and equivalent nonlinear stiffness coefficient, and the pipe size of the target pipe, determine the structural parameters of the pipe vibration absorber. The structural parameters include: the size of the elastic element (212), the distance between the arc mounting cavity (11) of the outer shell (1) and the oscillator (211) and the oscillator, the material, size and covering method of the damping element (22), and the size of the outer shell (1). S4. Based on the structural parameters, complete the processing and assembly of the outer shell (1), oscillator (211), elastic element (212) and damping element (22) to complete the design of the pipeline vibration absorber.

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