Modular cryogenic vibration damping device

Abstract

This invention discloses a modular cryogenic vibration damping device suitable for closed-loop cryogenic refrigeration systems. It can be installed as an independent module between the refrigeration unit and the cryogenic experimental platform. While ensuring low-temperature thermal conductivity and structural stability, it can suppress vibration propagation within different frequency ranges, causing vibration energy to attenuate and localize step-by-step within the periodic structure. Based on a multi-stage vibration damping system of a periodic mass-elastic coupling structure, and utilizing the regulating effect of the periodic structure on vibration propagation characteristics and the phonon flat-band localization vibration mechanism, this device effectively suppresses low-frequency vibrations and their harmonic components during refrigeration unit operation, thereby reducing the transmission of vibration to the cryogenic testing platform. This device, while ensuring low-temperature thermal conductivity and structural stability, can suppress vibration propagation within different frequency ranges, causing vibration energy to attenuate and localize step-by-step within the periodic structure.

Description

Technical Field

[0001] This invention belongs to the field of cryogenic scientific instruments and precision vibration control technology, specifically relating to a modular cryogenic vibration reduction device based on periodic structure vibration modulation and phonon flat-band mechanism, used for the suppression and isolation of mechanical vibration in closed-loop cryogenic refrigeration systems. By constructing a periodic mass-elastic coupling structure, the vibration propagation characteristics are modulated under cryogenic conditions. The attenuation and isolation of low-frequency mechanical vibrations and their harmonic components are achieved by utilizing the localized vibration modes in the periodic structure and the vibration propagation suppression effect within a specific frequency range. This device is suitable for various vibration-sensitive cryogenic precision measurement systems, including but not limited to scanning tunneling microscopes, cryogenic scanning probe systems, quantum computing and quantum sensing platforms, cryogenic spectroscopy measurement systems, superconducting device testing systems, and other closed-loop cryogenic experimental platforms. Background Technology

[0002] Closed-cycle cryogenic refrigeration systems are crucial foundational equipment in current low-temperature physics experiments, quantum materials research, and various precision measurement platforms. Compared to traditional liquid helium cooling, closed-cycle refrigerators do not require continuous consumption of liquid helium, offering advantages such as lower operating costs, longer continuous operating times, and easier maintenance. Therefore, they are widely used in cryogenic experimental platforms. Typical closed-cycle cryogenic refrigerators, such as the Gifford-McMahon refrigerator and pulse tube refrigerators, achieve cooling through periodic gas compression and expansion processes. Their operation is generally accompanied by periodic pressure pulsations and mechanical motion, inevitably generating mechanical vibrations. These vibrations propagate to the experimental platform through the refrigerator's support structure, mechanical connections, and heat-conducting components, and may form resonant coupling within the system structure, thus affecting the stability and measurement accuracy of the cryogenic experimental system.

[0003] Currently, for the vibration problem of closed-cycle refrigerators, existing technologies mainly adopt the following types of vibration reduction or isolation schemes: mechanical vibration isolation structures such as springs, rubber isolators, or air vibration isolation devices are installed between the refrigerator and the experimental platform to achieve basic isolation between the vibration source and the experimental platform; a passive vibration absorption unit is constructed using a mass-spring-damping structure, and vibration attenuation in a specific frequency band is achieved by adjusting the system's natural frequency; an active vibration control system is constructed using sensors and actuators to compensate and suppress detected vibration signals in real time; and vibration is attenuated step by step in multiple structural levels through multi-stage suspension structures or multi-path vibration decoupling structures.

[0004] The aforementioned technologies can reduce the impact of refrigerator vibration on experimental systems to some extent. However, most existing structures are designed for specific experimental setups and lack modular vibration damping units that can be independently integrated into different cryogenic platforms. Furthermore, most solutions rely primarily on single-stage vibration isolation or local structural optimization, which still has limitations in suppressing low-frequency and broadband vibrations. In addition, there is often a trade-off between stiffness and thermal conductivity between vibration isolation structures and cryogenic thermal conductive structures, making it difficult to achieve effective vibration isolation while ensuring cooling efficiency.

[0005] Therefore, it is necessary to propose a low-temperature vibration damping device that is universal, modularly integrateable, and capable of combining dynamic isolation performance and low-temperature thermal conductivity, in order to meet the low-vibration environment requirements of various precision measurement platforms in closed-loop cryogenic refrigeration systems.

[0006] The above-mentioned approach reduces the impact of closed-cycle refrigerator vibration on the cryogenic experimental system to some extent, but it still has the following limitations:

[0007] Insufficient low-frequency vibration suppression capability: Existing vibration isolation solutions mostly employ single-stage spring isolators, rubber vibration isolation pads, or simple mass-spring structures. Their vibration reduction performance is usually concentrated near a specific resonant frequency, making it difficult to achieve effective attenuation over a wide frequency band for low-frequency vibrations and their higher-order harmonic components generated during the operation of closed-cycle refrigerators. When there is a rigid or semi-rigid connection between the refrigerator cold head and the experimental platform, residual vibrations can still be transmitted to the low-temperature testing platform through structural coupling, thus affecting the stability of the precision measurement system. Insufficient decoupling of vibration transmission paths: Some existing technologies achieve vibration isolation only through a single vibration isolator or simple support structure. However, in actual cryogenic systems, vibration propagates not only through mechanical support structures but may also be coupled and transmitted through multiple paths such as thermally conductive components and structural connectors. Traditional thermally conductive connectors typically use rigid metal components, which significantly increase structural stiffness while ensuring good thermal conductivity, thus creating new vibration propagation paths and reducing the overall vibration isolation effect. Insufficient structural versatility and modularity: Existing vibration isolation structures are typically custom-designed for specific cryogenic experimental setups, with their structures often directly integrated into the cryogenic system, lacking independently installable and replaceable modular vibration damping units. Therefore, flexible configuration and rapid integration between different cryogenic experimental platforms are difficult to achieve, resulting in poor system adaptability and versatility. The challenge lies in balancing vibration isolation and cryogenic heat conduction: In cryogenic experimental systems, effective vibration isolation between the cryostat cold head and the experimental platform is crucial, while ensuring sufficient cryogenic heat transfer capacity. Traditional structures often reduce structural stiffness or add flexible connections to improve vibration isolation, potentially leading to decreased heat conduction. Conversely, rigid connections used to ensure efficient heat conduction can enhance vibration coupling. Therefore, achieving efficient vibration isolation while maintaining high cryogenic heat conduction efficiency remains a critical challenge in current technologies. Summary of the Invention

[0008] In view of this, the present invention provides a modular cryogenic vibration damping device, which is suitable for closed-loop cryogenic refrigeration systems. It can be installed as an independent module between the refrigeration unit and the cryogenic experimental platform. While ensuring low-temperature thermal conductivity and structural stability, it can suppress the propagation of vibration in different frequency ranges, so that the vibration energy is gradually attenuated and localized in the periodic structure.

[0009] The technical solution of this invention includes: a closed-loop refrigerator, a vacuum chamber, a cold plate with a cold stage structure, a cold shield, a small cold plate with a small cold stage structure, an upper connecting plate, a vibration damping module, a vibration damping platform, and a low-temperature testing platform. The closed-loop refrigerator is installed on top of the vacuum chamber, with its cold head extending vertically downwards into the vacuum chamber. The cold plate and small cold plate are positioned inside the vacuum chamber along the direction of the cold head, forming a multi-stage low-temperature environment together with the corresponding cold shield. The upper connecting plate is located below the small cold plate and is fixedly connected to it via a flange. The vibration damping module is located between the small cold plate and the low-temperature testing platform, situated on the main transmission path of refrigerator vibration propagating to the experimental area. It is used to isolate and attenuate the mechanical vibration generated during refrigerator operation, thereby reducing the transmission of vibration to the low-temperature testing platform. The lower end of the vibration damping module is connected to the low-temperature testing platform via the vibration damping platform, thus transmitting the low-vibration environment after vibration damping to the experimental system and supporting various low-temperature precision measurement modules.

[0010] Furthermore, the vibration damping module includes: an upper connecting plate, elastic elements, rigid connecting rods, a mass block, a vibration damping plate, a lower connecting plate, and a vibration damping platform. The upper and lower connecting plates are rigidly connected by multiple rigid connecting rods, forming a stable spatial frame structure to bear the load from the cold plate of the refrigeration unit's cold stage structure. The elastic elements are arranged between the upper and lower connecting plates and form a periodically distributed structure with the mass block. The vibration damping plate and the vibration damping platform are rigidly connected, transmitting the damped vibration signal to the vibration damping platform. The vibration damping platform, as the output end of the vibration damping module, is connected to the low-temperature testing platform for suspending and fixing experimental equipment.

[0011] Furthermore, a periodic vibration damping structure composed of multiple elastic elements and mass blocks is provided between the upper connecting plate and the vibration damping plate; the elastic elements are arranged regularly in the plane and form a multi-layer stacked structure in the vertical direction, thereby forming a three-dimensional periodically distributed elastic support system. Adjacent elastic elements are connected by mass blocks to form a mass-elastic coupling structure.

[0012] Furthermore, a damping plate is installed inside the damping module to bear the vibration load transmitted from the upper part and further transmit the attenuated vibration to the lower structure. The lower connecting plate has openings to reserve installation space for the thermally conductive connection structure and to avoid forming additional rigid contact paths in the structure, thereby reducing the possibility of vibration being transmitted through additional paths.

[0013] Furthermore, the mass block is a regular hexagonal prism structure, and each hexagonal prism mass block has a connection position on each of its six sides. The connection position is located at the geometric center of the corresponding side and is used to connect the elastic element. The connection positions include the center of the left side, the center of the right side, the center of the upper left slope, the center of the upper right slope, the center of the lower left slope, and the center of the lower right slope. Within the same layer, adjacent mass blocks are connected by elastic elements located at the center of the left and right sides, forming a continuous periodic connection structure along the array extension direction. Mass blocks located at the edge of the array are connected to the mass blocks at corresponding positions of adjacent periodic units in the same way, thereby ensuring that the entire array has a continuous mechanical coupling relationship in the plane. Between adjacent layers, elastic elements are connected to the center of the inclined surface of a hexagonal prism mass block. One set of elastic elements connects the center of the lower right inclined surface of the upper mass block to the center of the upper left inclined surface of the adjacent lower mass block; another set connects the center of the lower left inclined surface of the upper mass block to the center of the upper right inclined surface of the adjacent lower mass block. These two sets of oblique connections are staggered in opposite directions, creating a continuous cross-coupling structure between adjacent layers. The mass blocks in adjacent layers are arranged in a staggered manner, with the upper mass block located in the gap region formed by the lower adjacent mass block, thus creating a continuous triangular mechanical unit in space through the interlayer oblique connections. Through horizontal connections within the same layer and bidirectional oblique connections between layers, each mass block establishes an elastic coupling relationship with multiple surrounding mass blocks, thereby forming a three-dimensional lattice network in space composed of periodically repeating triangular units. This lattice network possesses both in-plane coupling and interlayer coupling capabilities, enabling vibrational energy to propagate in multiple directions and achieving vibration attenuation and elastic wave modulation within the target frequency range through local resonance effects.

[0014] Furthermore, the elastic element is made of copper alloy, beryllium copper, stainless steel, or other elastic materials.

[0015] Furthermore, the mass block is made of copper, copper alloy, stainless steel or other metal materials; Furthermore, the upper connecting plate, the lower connecting plate, and the rigid connecting rod are made of stainless steel, titanium alloy, copper alloy, or a combination thereof.

[0016] Beneficial effects: 1. This invention provides a modular cryogenic vibration damping device. Based on a multi-stage vibration attenuation system with a periodic mass-elastic coupling structure, this device utilizes the periodic structure's ability to regulate vibration propagation characteristics and the phonon flat-band localization vibration mechanism to effectively suppress low-frequency vibrations and their harmonic components during refrigerator operation, thereby reducing vibration transmission to the cryogenic testing platform. While ensuring low-temperature thermal conductivity and structural stability, this device can suppress vibration propagation across different frequency ranges, causing vibration energy to attenuate and localize step-by-step within the periodic structure. The vibration damping device of this invention can be installed as an independent module between the refrigerator and the cryogenic experimental platform. It features structural stability, excellent vibration damping performance, high modularity, adjustable parameters, and wide applicability, providing a stable low-vibration working environment for various cryogenic precision measurement systems.

[0017] 2. This invention provides a modular low-temperature vibration damping device. This device leverages the broadband vibration suppression capability of a three-dimensional periodic mass-elastic coupling structure. Unlike traditional low-temperature vibration damping devices that only employ simple vibration isolation structures such as single-stage springs, rubber pads, or bellows, this invention constructs a three-dimensional periodic array structure composed of multiple layers of elastic elements and mass blocks between the upper and lower connecting plates. Each elastic unit is coupled and connected through the mass blocks, forming a stable triangle or other periodic configuration in space, thus constituting a structural system with periodic mass-spring characteristics.

[0018] In this structure, external vibrations must pass through multiple coupling units sequentially during propagation. Their propagation characteristics no longer follow a simple single-degree-of-freedom isolation model, but rather undergo modulation and redistribution within a periodic structure. By rationally designing the mass block mass and the stiffness parameters of the elastic elements, a vibration propagation suppression zone can be formed within the target frequency range, and a localized vibration mode similar to a phonon band can be formed within a specific frequency range, thus confining vibration energy to some structural units. Compared to traditional structures that rely solely on single-stage isolation or unidirectional elastic support, this invention achieves a more uniform and stable vibration isolation effect in three dimensions and significantly reduces the transmission of closed-cycle refrigerator vibration to the precision measurement platform over a wider frequency range, improving the overall vibration resistance of the system.

[0019] 3. This invention provides a modular cryogenic vibration damping device that combines efficient low-temperature heat conduction with vibration isolation through a synergistic design of materials and structures. Key structural components, including an upper connecting plate, a lower connecting plate, a rigid connecting rod, and a mass block, are preferably made of materials with high thermal conductivity and stable low-temperature mechanical properties, such as oxygen-free copper, pure copper, aluminum alloys, or low-temperature stainless steel, to ensure good thermal conductivity and structural reliability in low-temperature environments. Elastic elements are made of metallic materials that maintain stable elastic properties under low-temperature conditions, such as beryllium copper alloys or stainless steel springs, ensuring that the vibration damping structure maintains its designed stiffness and elastic response characteristics in low-temperature environments. Through the synergistic design of the above material system, on the one hand, effective heat transfer between the cold source and the experimental platform is ensured, meeting the stable operation requirements of the cryogenic system; on the other hand, abnormal stiffness or vibration amplification problems caused by material performance degradation at low temperatures are avoided, thus achieving both reliable heat conduction and stable vibration damping under cryogenic conditions.

[0020] 4. This invention provides a modular cryogenic vibration damping device with adjustable parameters, offering broad applicability and scalability. The vibration damping structure adopts a modular design concept, where key parameters of its periodic structural units, including the number of elastic elements, the number of layers, the spatial arrangement, the mass of the mass blocks, and the connection method, can be flexibly adjusted according to different closed-cycle refrigerator types, load conditions, and vibration environments. By adjusting these parameters, the equivalent stiffness, natural frequency, and vibration propagation characteristics of the vibration damping module can be changed, thereby achieving customized suppression effects for vibration sources with different spectral characteristics. This structure is not only suitable for scanning probe systems such as scanning tunneling microscopes, but can also be extended to various vibration-sensitive precision measurement scenarios such as quantum computing platforms, cryogenic precision spectral measurement systems, and superconducting device testing systems. Compared to traditional vibration damping devices with fixed structures and limited applicability, this invention has stronger environmental adaptability and system integration flexibility, and can be widely applied as a general-purpose cryogenic vibration damping module in various precision experimental systems. Attached Figure Description

[0021] Figure 1 This is a structural diagram of the overall low-temperature experimental system in an embodiment of the present invention; Figure 2 This is a general structural diagram of the vibration reduction module in an embodiment of the present invention; Figure 3 The spring structure is hidden within, with only the mass blocks and structural connection nodes remaining, to more clearly demonstrate the spatial arrangement of the periodic structure and the interlayer connections.

[0022] Figure 4 A three-dimensional structural diagram of a 5×5 array, 20-layer periodic vibration damping structure; Figure 5 A three-dimensional structural diagram of a 5×5 array, 8-layer periodic vibration damping structure; Figure 6 A side view of the three-dimensional structure of a 5×5 array with 8 layers of periodic vibration damping. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] This invention proposes a modular cryogenic vibration damping device suitable for closed-loop cryogenic refrigeration systems. It suppresses mechanical vibrations generated during refrigeration operation and achieves efficient vibration isolation while ensuring low-temperature heat transfer capacity, thereby providing a stable, low-vibration operating environment for various cryogenic precision measurement systems. In this invention, "low temperature" refers to below 4K.

[0025] This invention is based on the design concept of multi-level mechanical vibration isolation, periodic structural vibration regulation, phonon flat zone localized vibration suppression, and decoupling of heat conduction and vibration transmission. By setting up modular vibration reduction units between the cold plate of the cold stage structure of the refrigerator and the low-temperature test platform, the vibration energy is gradually attenuated and the transmission is blocked.

[0026] like Figure 1 As shown, the overall cryogenic experimental system mainly includes: a closed-loop refrigerator 1, a vacuum chamber 2, a cold plate structure 3, a cold shield 4, a small cold plate 5, an upper connecting plate 6, a vibration damping module 7, a vibration damping platform 8, and a cryogenic testing platform 9. The closed-loop refrigerator 1 is installed on top of the vacuum chamber 2, with its cold head extending vertically downwards into the vacuum chamber. The cold plate 3 and the small cold plate 5 are positioned inside the vacuum chamber along the direction of the cold head, forming a multi-stage cryogenic environment together with the corresponding cold shield 4. The upper connecting plate 6 is located below the small cold plate 5 and is fixedly connected to it via a flange. The vibration damping module 7 is located between the small cold plate 5 and the cryogenic testing platform 9, situated on the main transmission path of the refrigerator's vibration propagating to the experimental area. It is used to isolate and attenuate the mechanical vibration generated during the refrigerator's operation, thereby reducing the transmission of vibration to the cryogenic testing platform 9. The lower end of the vibration damping module 7 is connected to the cryogenic testing platform 9 via the vibration damping platform 8, thus transmitting the low-vibration environment after vibration damping to the experimental system and supporting various cryogenic precision measurement modules.

[0027] The small cooling stage structure 5 referred to in this embodiment of the invention is Small cold plate 5 refers to a cold plate that can reach a lower temperature than cold plate 3.

[0028] 1. Overall structure of the vibration damping module like Figure 2As shown, the vibration damping module 7 mainly includes: an upper connecting plate 6, an elastic element 10, a rigid connecting rod 11, a mass block 12, a vibration damping plate 13, a lower connecting plate 16, and a vibration damping platform 8. The upper connecting plate 6 and the lower connecting plate 16 are rigidly connected by multiple rigid connecting rods 11, forming a stable spatial frame structure to bear the load from the cold plate of the refrigeration unit's cold stage structure.

[0029] The elastic element 10 is arranged between the upper connecting plate 6 and the lower connecting plate 16, and forms a periodic distribution structure with the mass block 12.

[0030] The vibration damping plate 13 is rigidly connected to the vibration damping platform 8, thereby transmitting the vibration signal after vibration damping to the vibration damping platform 8. The vibration damping platform 8, as the output end of the vibration damping module, is connected to the low-temperature test platform 9 and used to suspend and fix the experimental equipment.

[0031] 2. Periodically elastic vibration damping structure A periodic vibration damping structure consisting of multiple elastic elements 10 and mass blocks 12 is provided between the upper connecting plate 6 and the vibration damping plate 13. The elastic elements are arranged regularly in the plane and form a multi-layer stacked structure in the vertical direction, thereby constituting a three-dimensional periodically distributed elastic support system.

[0032] Adjacent elastic elements 10 are connected by mass blocks 12, forming a mass-elastic coupling structure. This structural design allows for the regulation of vibration propagation characteristics within the structure, suppressing or attenuating vibrations within a specific frequency range, thus achieving effective vibration control. This periodic structure provides graded vibration attenuation at multiple levels, which is beneficial for improving vibration reduction performance in low-frequency and wide-bandwidth ranges.

[0033] 4. Intermediate vibration-damping flat plate structure The vibration damping module is equipped with a vibration damping plate 13 to bear the vibration load transmitted from the upper part and further transmit the attenuated vibration to the lower structure.

[0034] The lower connecting plate 16 is provided with an opening 15 to reserve installation space for the thermally conductive connection structure and to avoid forming an additional rigid contact path in the structure, thereby reducing the possibility of vibration being transmitted through the additional path.

[0035] 5. Periodic array structure and spatial configuration In this embodiment of the invention, the mass block is a regular hexagonal prism structure. Each hexagonal prism mass block has a connection position on each of its six sides. The connection positions are located at the geometric center of the corresponding side and are used to connect to the elastic element. The connection positions include the center of the left side, the center of the right side, the center of the upper left slope, the center of the upper right slope, the center of the lower left slope, and the center of the lower right slope.

[0036] Within the same layer, adjacent mass blocks are connected by elastic elements located at the center of the left and right sides, forming a continuous periodic connection structure along the array's extension direction. Mass blocks located at the array edges are connected to their corresponding positions in adjacent periodic units in the same way, ensuring continuous mechanical coupling within the plane for the entire array.

[0037] Between adjacent layers, elastic elements are connected to the center of the inclined surface of a hexagonal prism mass block. Some of these elastic elements connect the center of the lower right inclined surface of the upper mass block to the center of the upper left inclined surface of the adjacent lower mass block; others connect the center of the lower left inclined surface of the upper mass block to the center of the upper right inclined surface of the adjacent lower mass block. These two sets of inclined connections are staggered in opposite directions, creating a continuous cross-coupling structure between adjacent layers. The mass blocks in adjacent layers are arranged in a staggered manner, with the upper mass block located in the gap region formed by the lower adjacent mass block, thus creating a continuous triangular mechanical unit in space through the interlayer inclined connections.

[0038] Through horizontal connections within the same layer and bidirectional oblique connections between layers, each mass block establishes an elastic coupling relationship with multiple surrounding mass blocks, thereby forming a three-dimensional lattice network in space composed of periodically repeating triangular units. This lattice network possesses both in-plane coupling and interlayer coupling capabilities, enabling vibrational energy to propagate in multiple directions and achieving vibration attenuation and elastic wave modulation within the target frequency range through local resonance effects.

[0039] To further illustrate the spatial arrangement and connection relationship of the periodic vibration reduction structure of the present invention, such as Figures 3-6 As shown, schematic diagrams of periodic structures under different array sizes and number of layers are presented.

[0040] Figure 3 The spring structure is hidden within the diagram, with only the mass blocks and structural connection nodes remaining, to more clearly demonstrate the spatial arrangement of the periodic structure and the interlayer connections. From left to right in the diagram are: a 6-layer periodic unit with a 10×10 array of double-sided periodic structures; a 10-layer periodic unit with a 10×10 array of double-sided periodic structures; and a 10-layer periodic unit with a 15×15 array of double-sided periodic structures. Figure 3 This viewpoint, taken from the xz direction, shows the layered stacking structure in the vertical direction.

[0041] Figure 4 This is a 3D structural diagram of a 5×5 array, 20-layer periodic damping structure. To more clearly illustrate the internal connections of the periodic structure, the springs and intermediate plate structures are hidden in the diagram; only the mass blocks and connecting nodes are shown, along with the spatial structural forms from different directional perspectives.

[0042] Figure 5This is a 3D structural diagram of a 5×5 array, 8-layer periodic damping structure. A simple triangular array structure is used in the diagram to more clearly illustrate the arrangement of the mass blocks. The diagram provides xz and yz perspectives.

[0043] Figure 6 This is a side-view 3D structural diagram of a 5×5 array, 8-layer periodic damping structure. The connection method is more clearly shown through the side view and magnification.

[0044] In different implementations, the periodic vibration damping structure can be designed with different array sizes and number of layers according to the vibration environment and load requirements. By adjusting the array size, number of layers, and mass block distribution, the equivalent stiffness, mass distribution, and vibration propagation characteristics of the overall structure can be changed, thereby achieving optimized suppression effects for vibrations in different frequency ranges.

[0045] 6. Vibration Suppression Principle Based on Phonon Flat-Zone Mechanism The periodic vibration damping structure in this invention consists of periodically distributed mass blocks and elastic elements, forming a regularly arranged mass-elastic coupling system in space. When mechanical vibrations generated by the refrigerator are transmitted into this periodic structure, the vibrations are modulated by the periodic structural units during propagation within the structure, thereby altering the vibration propagation characteristics. Within a specific frequency range, the periodic structure can form localized vibration modes similar to phonon bands, confining vibration energy within certain structural units and reducing the propagation efficiency of vibrations in the overall structure, thus effectively suppressing low-frequency vibrations and their harmonic components. Unlike traditional single-stage spring vibration isolation structures that primarily rely on low stiffness for vibration isolation, this invention regulates vibration propagation behavior through a periodic mass-elastic coupling structure, causing reflection, coupling, and localization effects in multi-stage coupling units, improving the overall structure's vibration damping performance in low-frequency and wide-frequency ranges. Furthermore, by adjusting structural parameters such as the mass of the mass blocks, the stiffness of the elastic elements, the array size, and the number of layers, the dynamic characteristics and vibration propagation modes of the structure can be altered to adapt to the vibration damping requirements of different low-temperature experimental platforms and different vibration environments.

[0046] 1. Modular Low-Temperature Vibration Damping Structure: This invention proposes a modular vibration damping structure positioned between the cold plate of the cold stage structure in a closed-loop low-temperature refrigeration system and the low-temperature testing platform. This structure includes an upper connecting plate 6, a lower connecting plate 16, a periodic vibration damping unit, a vibration damping plate 13, and a vibration damping platform 8. The upper connecting plate 6 is connected to the cold plate of the cold stage structure of the refrigeration unit, and the vibration damping platform 13 is connected to the low-temperature testing platform, thus forming an independent vibration isolation module between the refrigeration system and the experimental platform. This achieves graded attenuation and isolation of vibration, exhibiting good versatility and integrability.

[0047] 2. Periodic Mass-Elastic Coupling Vibration Reduction Structure: A periodic structure consisting of elastic elements 10 and mass blocks 12 is set between the upper connecting plate 6 and the damping plate 13. Adjacent elastic elements 10 are connected by mass blocks, thus forming a mass-elastic coupling system. This structure regulates the propagation characteristics of vibration in the structure through periodically distributed mass and elastic parameters, causing reflection, coupling, and localization effects of vibration in multi-level coupling units. Within a specific frequency range, the periodic structure can form a localized vibration mode similar to a phonon band, thereby reducing the propagation efficiency of vibration in the structure and effectively suppressing low-frequency and broadband vibrations. Specifically: the elastic elements can be made of metal or alloy materials with good elasticity and thermal conductivity at low temperatures, such as copper alloys, beryllium copper, stainless steel, or other elastic materials; the mass blocks can be made of high-density materials, such as copper, copper alloys, stainless steel, or other metal materials; the upper connecting plate, lower connecting plate, and rigid connecting rod can be made of metal materials with both mechanical strength and thermal conductivity, such as stainless steel, titanium alloys, copper alloys, or combinations thereof.

[0048] 3. Three-dimensional periodic array and parameter-adjustable vibration damping structure: The periodic vibration damping structure forms a multi-layer periodic array in space, with each elastic element connected by mass blocks to form a three-dimensional distributed elastic network structure. The elastic elements can adopt triangular arrays, square arrays, hexagonal arrays, or other periodic arrangements in the planar direction, and form a multi-layer stacked structure in the vertical direction.

[0049] This structure employs a parametric design, with adjustable parameters including, but not limited to, the number of elastic elements, the mass of the mass blocks, the number of array layers, and the spatial arrangement. By adjusting these parameters, the overall stiffness, natural frequency, and vibration propagation characteristics of the system can be altered, thereby achieving adaptation and optimization for different vibration environments.

[0050] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., 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 modular cryogenic vibration damping device, characterized in that, include: Closed-loop refrigeration unit (1), vacuum chamber (2), cold plate (3), cold shield (4), small cold plate (5), upper connecting plate (6), vibration damping module (7), vibration damping platform (8) and low temperature testing platform (9); The closed-loop refrigerator (1) is installed on the top of the vacuum chamber (2), and its cold head extends vertically downward into the interior of the vacuum chamber; The cold plate (3) and the small cold plate (5) are arranged inside the vacuum cover along the direction of the cold head, and together with the corresponding cold screen (4), they form a multi-level low-temperature environment; The upper connecting plate (6) is located below the small cold plate (5) and is fixedly connected to the small cold plate (5) by means of a flange; The vibration damping module (7) is located between the small cold plate (5) and the low-temperature test platform (9), on the main transmission path of the refrigeration machine vibration to the experimental area. It is used to isolate and attenuate the mechanical vibration generated during the operation of the refrigeration machine, thereby reducing the transmission of vibration to the low-temperature test platform (9). The lower end of the vibration damping module (7) is connected to the low-temperature test platform (9) through the vibration damping platform (8), thereby transmitting the low-vibration environment after vibration damping treatment to the experimental system and supporting various low-temperature precision measurement modules.

2. The modular cryogenic vibration damping device as described in claim 1, characterized in that, The vibration damping module (7) includes: an upper connecting plate (6), an elastic element (10), a rigid connecting rod (11), a mass block (12), a vibration damping plate (13), a lower connecting plate (16), and a vibration damping platform (8); Among them: the upper connecting plate (6) and the lower connecting plate (16) are rigidly connected by multiple rigid connecting rods (11) to form a stable spatial frame structure for bearing the load from the cold plate of the refrigeration unit; The elastic element (10) is arranged between the upper connecting plate (6) and the lower connecting plate (16), and forms a periodic distribution structure with the mass block (12); The vibration damping plate (13) and the vibration damping platform (8) are fixedly connected by a rigid connection, so that the vibration signal after vibration damping is transmitted to the vibration damping platform (8); The vibration damping platform (8) serves as the output end of the vibration damping module and is connected to the low-temperature test platform (9) for suspending and fixing experimental equipment.

3. The modular low-temperature vibration damping device as described in claim 1, characterized in that, A periodic vibration damping structure consisting of multiple elastic elements (10) and a mass block (12) is provided between the upper connecting plate (6) and the vibration damping plate (13); the elastic elements are arranged regularly in the plane and form a multi-layer stacked structure in the vertical direction, thereby forming a three-dimensional periodically distributed elastic support system. Adjacent elastic elements (10) are connected by mass blocks (12) to form a mass-elastic coupling structure.

4. The modular cryogenic vibration damping device as described in claim 1, characterized in that, A damping plate (13) is installed inside the damping module to bear the vibration load transmitted from the upper part and further transmit the attenuated vibration to the lower structure. The lower connecting plate (16) is provided with an opening (15) to reserve installation space for the heat-conducting connection structure and to avoid forming an additional rigid contact path in the structure, thereby reducing the possibility of vibration being transmitted through the additional path.

5. A modular cryogenic vibration damping device as described in claim 1, characterized in that, The mass block (12) is a regular hexagonal prism structure. Each hexagonal prism mass block has a connection position on each of its six sides. The connection position is located at the geometric center of the corresponding side and is used to connect the elastic element (10). The connection position includes the center of the left side, the center of the right side, the center of the upper left slope, the center of the upper right slope, the center of the lower left slope, and the center of the lower right slope. Within the same layer, adjacent mass blocks are connected by elastic elements located at the center of the left and right sides, forming a continuous periodic connection structure along the array extension direction. Mass blocks located at the edge of the array are connected to the mass blocks at corresponding positions of adjacent periodic units in the same way, thereby ensuring that the entire array has a continuous mechanical coupling relationship in the plane. Between two adjacent layers, elastic elements are connected to the center of the inclined surface of the hexagonal prism mass block; among them, some elastic elements connect the center of the lower right inclined surface of the upper layer mass block to the center of the upper left inclined surface of the adjacent lower layer mass block; the other set of elastic elements connects the center of the lower left inclined surface of the upper layer mass block to the center of the upper right inclined surface of the adjacent lower layer mass block; the two sets of inclined connections are staggered in opposite directions, so that a continuous cross-coupling structure is formed between adjacent layers; the mass blocks in adjacent layers are arranged in a staggered manner, with the upper layer mass block located in the gap area formed by the lower layer adjacent mass block, so that the interlayer inclined connections form a continuous triangular mechanical unit in space; Through horizontal connections within the same layer and bidirectional oblique connections between layers, each mass block establishes an elastic coupling relationship with multiple surrounding mass blocks, thereby forming a three-dimensional lattice network in space composed of periodically repeating triangular units. This lattice network simultaneously possesses in-plane coupling and inter-layer coupling capabilities, enabling vibrational energy to propagate in multiple directions and achieving vibration attenuation and elastic wave modulation within the target frequency range through local resonance effects.

6. A modular cryogenic vibration damping device as described in claim 2, characterized in that, The elastic element (10) is made of copper alloy, beryllium copper, stainless steel or other elastic materials.

7. A modular low-temperature vibration damping device as described in claim 2, characterized in that, The mass block (12) is made of copper, copper alloy, stainless steel or other metal materials.

8. A modular cryogenic vibration damping device as described in claim 1, characterized in that, The upper connecting plate (6), the lower connecting plate (16), and the rigid connecting rod (11) are made of stainless steel, titanium alloy, copper alloy, or a combination thereof.

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