CN116645943A - Elastic metamaterial unit and vibration reduction method adopting same - Google Patents
Elastic metamaterial unit and vibration reduction method adopting same Download PDFInfo
- Publication number
- CN116645943A CN116645943A CN202310557456.7A CN202310557456A CN116645943A CN 116645943 A CN116645943 A CN 116645943A CN 202310557456 A CN202310557456 A CN 202310557456A CN 116645943 A CN116645943 A CN 116645943A
- Authority
- CN
- China
- Prior art keywords
- elastic
- metamaterial unit
- elastic metamaterial
- vibrator
- unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 12
- 230000009467 reduction Effects 0.000 title abstract description 21
- 238000013016 damping Methods 0.000 claims abstract description 57
- 230000000694 effects Effects 0.000 claims abstract description 25
- 238000007667 floating Methods 0.000 claims description 49
- 239000000463 material Substances 0.000 claims description 24
- 230000004044 response Effects 0.000 claims description 20
- 238000004088 simulation Methods 0.000 claims description 16
- 230000008878 coupling Effects 0.000 claims description 11
- 238000010168 coupling process Methods 0.000 claims description 11
- 238000005859 coupling reaction Methods 0.000 claims description 11
- 239000000758 substrate Substances 0.000 claims description 10
- 239000011159 matrix material Substances 0.000 claims description 7
- 239000013013 elastic material Substances 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 5
- 238000004806 packaging method and process Methods 0.000 claims description 4
- 230000002040 relaxant effect Effects 0.000 claims 1
- 238000010008 shearing Methods 0.000 abstract description 2
- 229920001971 elastomer Polymers 0.000 description 13
- 229910000831 Steel Inorganic materials 0.000 description 10
- 239000010959 steel Substances 0.000 description 10
- 238000006073 displacement reaction Methods 0.000 description 9
- 238000013461 design Methods 0.000 description 8
- 230000001629 suppression Effects 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 5
- 230000001965 increasing effect Effects 0.000 description 4
- 238000009434 installation Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 230000005284 excitation Effects 0.000 description 3
- 238000005457 optimization Methods 0.000 description 3
- 230000000737 periodic effect Effects 0.000 description 3
- 238000004026 adhesive bonding Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000011089 mechanical engineering Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000021715 photosynthesis, light harvesting Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Vibration Prevention Devices (AREA)
Abstract
The invention relates to an elastic metamaterial unit and a vibration reduction method adopting the elastic metamaterial unit, wherein the elastic metamaterial unit comprises the following components: an outer case, a plurality of vibrator units of different resonance frequencies provided in the outer case; in the outer shell, a plurality of vibrator units are sequentially arranged along the vertical direction, and the vibrator units which are adjacent up and down are arranged at intervals; the vibrator unit includes: a rigid, vertical mass and flexible side connector; the side connecting pieces are respectively arranged on two opposite sides of the three-dimensional mass block, and the side connecting pieces are connected with the shell body. According to the elastic metamaterial unit, the shearing strain of the side connecting piece is utilized, the damping effect of the elastic metamaterial unit can be utilized to a large extent, and the damping frequency band of the metamaterial unit is widened through the damping structural piece, so that an excellent vibration control effect is obtained.
Description
Technical Field
The invention relates to the field of vibration and noise control, in particular to an elastic metamaterial unit and a vibration reduction method adopting the elastic metamaterial unit.
Background
Structural vibrations and noise are widely present in the field of mechanical engineering. Vibration and noise not only can directly affect the performance of a mechanical device, but also can cause serious accidents such as out of control, structural fatigue damage, fracture, explosion disintegration and the like. Materials and structures with vibration suppression characteristics are designed and used for structural design of mechanical equipment, and the method has important significance in improving the overall performance of the equipment, enhancing the safety of the equipment and prolonging the service life of the equipment. However, the conventional dynamic vibration absorbing and damping technology has difficulty in better solving the low-frequency and broadband vibration problems widely faced in the equipment.
Both vibration and sound waves propagate in the form of elastic waves. The elastic metamaterial refers to an artificial metamaterial/structure with elastic wave sub-wavelength regulation and control characteristics, and is usually a periodic structure. The properties of metamaterials often do not depend on the properties of the constituent materials, but rather on the coupling characteristics between the artificial microstructure units (i.e., cells) and the elastic waves.
Research for over ten years shows that the band gap energy of the elastic metamaterial designed based on the local resonance mechanism can effectively inhibit the propagation of elastic waves, and a new technical approach is provided for breaking through the bottleneck of the traditional vibration reduction technology. However, the elastic metamaterial design theory cannot coordinate the contradiction between light weight, low frequency and broadband elastic wave suppression. Furthermore, a metamaterial spectrum passband of limited size is composed of dense formants, and the larger the number of cells, the larger the number of formants in the passband. That is, the narrow band elastic wave band gap of the elastic metamaterial can attenuate structural vibration, but the response in a wider passband is resonance amplified.
The damping effect can effectively reduce the vibration of the structure, so that the damping effect is widely applied to the field of vibration control, but the damping coefficient is highly dependent on the material, the damping coefficient of most metal materials is limited, and the rigidity of materials with higher damping coefficient such as rubber often cannot meet the requirements of mechanical devices. The vibration damping effect of the conventional damping vibration damping technology such as a damper depends on the vibration frequency, and the lower the vibration frequency is, the poorer the vibration damping effect is, so that the means such as the damper still cannot effectively cope with the low-frequency vibration of the structure.
The damping effect is applied to the metamaterial cell design, so that vibration in the passband of the elastic metamaterial can be effectively inhibited. The vibrators with different resonance frequencies are designed in the metamaterial unit cells, and the vibration reduction frequency band of the metamaterial can be widened through high damping material coupling, and meanwhile, the damping effect of the material can be utilized to a greater extent through proper structural design. The design method can effectively restrain the vibration of the mechanical structure.
For large floating structures, vibration reduction means based on elastic metamaterial technology often face the following conditional constraints:
(1) The weight is small and the large-scale distributed arrangement cannot be completely realized.
(2) The spatial layout positions are limited, and ideal periodic arrangement cannot be realized.
(3) The mode is difficult to accurately predict, and the mode peak point cannot be prevented from being confirmed.
A reasonable metamaterial unit layout is needed to address the above issues. By comprehensively considering the vibration energy paths, the layout mode of the elastic metamaterial can be optimized, so that the optimal vibration control effect is obtained under the condition of small additional mass ratio.
Disclosure of Invention
The invention aims to provide an elastic metamaterial unit and a vibration reduction method adopting the elastic metamaterial unit.
To achieve the above object, the present invention provides an elastic metamaterial unit comprising: an outer case, a plurality of vibrator units of different resonance frequencies provided in the outer case;
in the outer shell, a plurality of vibrator units are sequentially arranged along the vertical direction, and the vibrator units which are adjacent up and down are arranged at intervals;
the vibrator unit includes: a rigid, vertical mass and flexible side connector;
the side connecting pieces are respectively arranged on two opposite sides of the three-dimensional mass block, and the side connecting pieces are connected with the shell body.
According to one aspect of the invention, the vibrator units adjacent to each other vertically are optionally connected by a damping structural member; the upper end and the lower end of the damping structural member are respectively connected with the three-dimensional mass blocks of the vibrator unit.
According to an aspect of the present invention, the resonance frequency of the cubic mass of each vibrator unit in the vertical direction is different.
According to one aspect of the invention, the resonance frequency of the vibrator unit is adjusted by changing the characteristic parameters of the side connecting piece, and the device is used for realizing that the three-dimensional mass block in the vibrator unit generates a plurality of low-frequency resonance modes in a three-dimensional direction; wherein the characteristic parameter is at least one of hardness, shape and material.
According to an aspect of the present invention, the vibrator unit further includes: a frequency modulation structural member;
the frequency modulation structural member is detachably connected with the three-dimensional mass block, and the connection position of the frequency modulation structural member and the three-dimensional mass block is different from one side of the three-dimensional mass block connected with the side connecting piece.
According to an aspect of the present invention, the stereoscopic mass block in the vibrator unit may be provided as a cylinder, a rectangular parallelepiped, or a prism;
the damping structure member may be provided as a cylinder, sphere, cuboid or prism.
According to one aspect of the invention, the side connector is made of an elastic material with a damping coefficient higher than 0.15;
the damping structural member is made of an elastic material with a damping coefficient higher than 0.15.
According to one aspect of the invention, the outer housing comprises: the packaging device comprises a base, a bearing side plate arranged on the base, a top plate supported on the bearing side plate, and a packaging side plate connected with the bearing side plate and the top plate;
the bearing side plates are detachably connected with the base, and two bearing side plates are symmetrically arranged;
the top plate is detachably connected with the bearing side plate;
two packaging side plates are symmetrically arranged;
the side connecting piece of the vibrator unit is connected with the side face of the bearing side plate.
According to one aspect of the invention, the spacing distance between the two opposite load bearing side plates is adjustable for compressing or releasing the side edge connectors.
In order to achieve the above object, the present invention provides a vibration damping method using the elastic metamaterial unit, including:
determining a target structure, and establishing a simulation model for the target structure; wherein the target structure is a floating structure comprising: a floating substrate and a flexible support for supporting the floating substrate;
adding a vibration response based on the simulation model, and arranging the elastic metamaterial unit on the simulation model and performing simulation; wherein, the anti-resonance acting force of the elastic metamaterial unit acts on the matrix resonance of the floating matrix, and the damping formed by coupling resonance acts on broadband vibration;
and (3) comparing the front-back vibration response of the elastic metamaterial unit with the simulation model, optimizing the layout mode of the elastic metamaterial based on the comparison result, and obtaining the optimal vibration control effect under the condition of small additional mass ratio, wherein a plurality of elastic metamaterial units are respectively arranged on key energy passage nodes when the floating substrate vibrates, and the key energy passage nodes are positioned above the flexible support.
According to one scheme of the invention, the elastic metamaterial unit is designed, wherein the three-dimensional mass block is connected to the bearing side plate through the flexible side connecting piece to form a local resonance oscillator; the vibrators with different resonance frequencies can be obtained by controlling the shape and the hardness of the side connecting piece, and the two vibrators are connected through the damping structural piece to generate coupling; the frequency modulation plates can be arranged on the mass blocks of the vibrators, and the resonance frequency of the vibrators can be adjusted by increasing or decreasing the number of frequency modulation structural members, so that the use flexibility of the vibrator is improved very effectively.
According to one scheme of the invention, the elastic metamaterial units are periodically arranged and installed on a base structure needing vibration reduction to construct the elastic metamaterial structure for controlling the vibration of the base structure. For a large-scale floating structure, the layout mode of the elastic metamaterial can be optimized by comprehensively considering the passage of vibration energy, so that the optimal vibration control effect is obtained under the condition of small additional mass ratio.
According to the scheme of the invention, the elastic metamaterial unit provided by the invention can utilize the damping effect of the side connecting piece to a greater extent by utilizing the shear strain of the side connecting piece, and the damping frequency band of the metamaterial unit is widened by the damping structural piece. For a large-scale floating structure, the path of vibration energy can be comprehensively considered according to the limitation of the installation condition, and the layout mode of the elastic metamaterial is optimized, so that the optimal vibration control effect is obtained under the condition of small additional mass ratio.
Drawings
FIG. 1 is a perspective view schematically illustrating an elastic metamaterial unit according to one embodiment of the present invention;
FIG. 2 is an exploded view schematically showing an elastic metamaterial unit according to one embodiment of the present invention;
FIG. 3 is a perspective view schematically illustrating an elastic metamaterial unit according to another embodiment of the present invention;
fig. 4 is a schematic diagram schematically showing vibration conditions of a simplified structure of a large floating structure in embodiment 1;
FIG. 5 is a schematic diagram schematically showing the placement of the elastic metamaterial unit in example 1 on a large floating structure;
FIG. 6 is a graph schematically showing the vibrational response of a large floating structure in three cases in example 1;
fig. 7 is a schematic representation of the modes of the vibrator unit above in the elastic metamaterial unit (1) of embodiment 1 at different vibration frequencies;
FIGS. 8 (a), 8 (b) and 8 (c) are schematic illustrations of the modes of the floating structure at 50Hz, 112Hz and 147Hz vibration frequencies after the elastic metamaterial unit is added in example 1;
fig. 9 is a graph schematically showing the displacement in the vertical direction (Z) and the Total displacement (Total) of each vibrator of the metamaterial unit in example 1;
FIG. 10 is a schematic representation of the placement of the optimized elastic metamaterial unit of example 1 on a large floating structure;
fig. 11 is a graph schematically showing the vibration response of the large floating structure before and after optimization in example 1.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
In describing embodiments of the present invention, the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer" and the like are used in terms of orientation or positional relationship based on that shown in the drawings, which are merely for convenience of description and to simplify the description, rather than to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and thus the above terms should not be construed as limiting the present invention.
The present invention will be described in detail below with reference to the drawings and the specific embodiments, which are not described in detail herein, but the embodiments of the present invention are not limited to the following embodiments.
Referring to fig. 1 and 2, according to an embodiment of the present invention, an elastic metamaterial unit of the present invention includes: an outer case 1, and a plurality of transducer units 2 provided in the outer case 1. In the present embodiment, the resonance frequencies of the plurality of transducer units 2 are different. In the present embodiment, the outer case 1 has a rectangular hollow structure, and the plurality of vibrator units 2 are all mounted in the outer case 1; the vibrator units 2 are sequentially arranged in the vertical direction, and an interval is arranged between the vibrator units 2 which are adjacent up and down. In the present embodiment, the vibrator unit 2 includes: a rigid solid mass 21 and flexible side links 22; wherein, the side connecting pieces 22 are respectively arranged at two opposite sides of the three-dimensional mass block 21, and the side connecting pieces 22 are connected with the outer shell 1.
As shown in connection with fig. 1 and 2, according to one embodiment of the invention, the side connection 22 is made to the connection of the vertical mass 21 and the outer shell 1 by gluing, vulcanizing or the like. In this embodiment, if the side connecting pieces 22 are connected by gluing, the sides of the opposite sides of the side connecting pieces 22 are coated with glue, so that the opposite sides of the side connecting pieces 22 are glued with the whole surfaces of the three-dimensional mass block 21 and the outer housing 1, respectively.
Through the arrangement, the connection strength and stability between the side connecting pieces are effectively ensured, and meanwhile, the influence on the internal shearing strain of the side connecting pieces 22 is effectively avoided, so that the vibration reduction effect of the invention is ensured.
As shown in connection with fig. 1 and 2, according to one embodiment of the present invention, the side of the side connecting member 22 on the side where the three-dimensional mass 21 is connected is smaller than or equal to the side of the connected three-dimensional mass 21.
As shown in fig. 1 and 2, according to an embodiment of the present invention, the vibrator units 2 adjacent to each other vertically are optionally connected by using a damping structure 3; the upper and lower ends of the damping structural member 3 are respectively connected with a three-dimensional mass block 21 of the vibrator unit 2.
As shown in connection with fig. 1 and 2, according to an embodiment of the present invention, the resonance frequency of the vertical mass 21 of each vibrator unit 2 is different in the vertical direction.
As shown in fig. 1 and 2, according to an embodiment of the present invention, the resonance frequency of the vibrator unit 2 is adjusted by changing the characteristic parameters of the side connection member 22, and the device is used to generate a plurality of low-frequency resonance modes in different directions (e.g., three-dimensional XYZ directions) of the neutral mass 21 in the vibrator unit 2; wherein the characteristic parameter is at least one of hardness, shape and material. For example, when two vibrator units 2 are provided, at least one parameter of hardness, shape, and material of the side connectors 22 in the upper and lower vibrator units 2 is different from each other, so that the resonance frequencies of the upper and lower vibrator units 2 are different. When the vibrator unit 2 is provided with more, at least one parameter of the hardness, shape, material of the respective side connectors 22 is different.
As shown in fig. 1 and 2, according to an embodiment of the present invention, the vibrator unit 2 further includes: a frequency modulated structure 23. In the present embodiment, the tuning structure 23 is plate-shaped as a whole, and is used to adjust the mass of the entire vibrator unit 2, thereby adjusting the resonance frequency of the vibrator unit 2. Furthermore, the frequency modulation structural member 23 is detachably connected with the three-dimensional mass block 21, so that corresponding replacement adjustment can be conveniently carried out according to different requirements. In the present embodiment, the connection position of the tuning structure 23 and the cubic mass 21 is different from the side of the cubic mass 21 to which the side connector 22 is connected. For example, when the side connection members 22 are provided on both left and right sides of the three-dimensional mass 21, the frequency modulation structural members 23 are provided on either one of the front and rear sides of the three-dimensional mass 21 or on both sides, respectively. In this embodiment, in order to facilitate the detachable installation of the frequency modulation structural member 23, the frequency modulation structural member may be fixed by adopting a threaded connection member, so that the installation is stable and reliable, and the frequency modulation structural member does not occupy an excessive space.
As shown in connection with fig. 1 and 2, according to an embodiment of the present invention, the solid mass 21 in the vibrator unit 2 may be provided as a rectangular parallelepiped (fig. 1), a cylindrical (fig. 3), or a prismatic body. In the present embodiment, when the vibrator unit 2 is provided in plural, the three-dimensional mass 21 in the plurality of vibrator units 2 differs in resonance frequency, and further at least one characteristic parameter such as shape, volume, material, and the like is different. By adjusting the setting form (such as shape, volume, material, etc.) of the three-dimensional mass block 21, the three-dimensional mass block 21 can have different resonance frequencies respectively, and further the resonance frequency of the vibrator unit 2 is directly affected, so that the flexible adjustment of the vibration mode and the coupling state between different vibrators in the scheme is realized, and different vibration reduction effects are generated.
In the present embodiment, the damping structure 3 may be provided as a cylinder, a sphere, a cuboid or a prism. In the present embodiment, the arrangement form of the damper structural member 3 can be adjusted accordingly according to the arrangement form of the three-dimensional mass 21, for example, the arrangement shape of the damper structural member 3 is kept identical to the arrangement shape of the three-dimensional mass 21. Of course, the shape of the damping structure 3 may be different from the shape of the structure 21.
Referring to fig. 1 and 2, according to one embodiment of the present invention, the side connector 22 is made of an elastic material having a damping coefficient higher than 0.15; for example, the side connector 22 may be provided as a rubber block.
As shown in connection with fig. 1 and 2, according to one embodiment of the invention, the damping structure 3 is made of an elastic material with a damping coefficient higher than 0.15; for example, the damping structure 3 is made of rubber.
As shown in conjunction with fig. 1 and 2, according to one embodiment of the present invention, an outer housing 1 includes: a base 11, a load-bearing side plate 12 provided on the base 11, a top plate 13 supported on the load-bearing side plate 12, and a package side plate 14 connected to the load-bearing side plate 12 and the top plate 13. In the present embodiment, the base 11 has a plate-like structure, and is a base for connecting the entire outer case 1 to other structures. In the present embodiment, the load-bearing side plate 12 is supported by the base 11, and is a main structure for connecting the vibrator unit 2. In the present embodiment, the bearing side plates 12 are detachably connected with the base 11, and two bearing side plates 12 are symmetrically arranged; wherein the load-bearing side plate 12 comprises: the bearing plate body is provided with a bottom end connecting part and a top end connecting part which are respectively arranged at the upper end and the lower end of the bearing plate body; the bottom end connection portion and the top end connection portion are respectively arranged perpendicular to the bearing plate body and extend towards opposite directions respectively for being respectively connected with the base 11 and the top plate 13. In this embodiment, the bearing side plate 12 is connected with the base 11 by a threaded connection member, and a corresponding hole site can be provided at the bottom end connection portion to achieve the connection function.
In the present embodiment, the top plate 13 is supported against the top end connecting portion of the load-bearing side plate 12; wherein the top plate 13 is detachably connected with the bearing side plate 12; specifically, the top plate 13 and the bearing side plate 12 are connected by a threaded connection, wherein the connection is realized by arranging corresponding hole sites on the top connecting part of the bearing side plate 12.
In this embodiment, the top plate 13 is a rectangular plate body, and through holes are correspondingly formed at positions where the top plate and the bearing side plates 12 are connected to each other, so as to enable the threaded connection to pass through.
In the present embodiment, two package side plates 14 are symmetrically provided with each other; the package side plate 14 is a rectangular plate body, and in order to connect the top plate 13 and the load-bearing side plate 12, a through hole is provided at an edge position corresponding to the package side plate 14, and a threaded connection piece can pass through and be connected with a threaded hole on a corresponding structure.
In the present embodiment, the side connector 22 of the vibrator unit 2 is connected to the side surface of the load-bearing side plate 12.
As shown in connection with fig. 1 and 2, according to one embodiment of the present invention, the separation distance between the opposing load bearing side panels 12 is adjustable for use in compressing or releasing the side connector 22. In the present embodiment, the adjustment of the relative position is achieved by providing the through hole at the screw connection position as a oblong hole. Specifically, the bearing side plate 12 is connected with the base 11 through a bottom end connecting portion, wherein a threaded hole is formed in the base 11, a through hole for a threaded connector to pass through is formed in the bottom end connecting portion, and in order to achieve position adjustment of the bearing side plate 12, the through hole can be formed in the bottom end connecting portion to be a slotted hole, so that adjustment when the position of the bearing side plate 12 is fixed on the base 11 is achieved. Correspondingly, a threaded hole for connecting a threaded connector is formed in the top end connecting portion of the bearing side plate 12, a through hole for the threaded connector to pass through is formed in the top plate 13, and a long round hole is correspondingly formed in the through hole, so that the connection position of the bearing connecting plate 12 and the top plate 13 can be adjusted conveniently.
According to an embodiment of the present invention, a vibration damping method using the aforementioned elastic metamaterial unit according to the present invention includes:
determining a target structure, and establishing a simulation model for the target structure; wherein the target structure is a floating structure comprising: a floating substrate and a flexible support for supporting the floating substrate;
adding vibration response based on the simulation model, and arranging an elastic metamaterial unit on the simulation model and performing simulation; wherein, the anti-resonance acting force of the elastic metamaterial unit acts on the matrix resonance of the floating matrix, and the damping formed by coupling resonance acts on broadband vibration;
and (3) comparing the front-back vibration response of the elastic metamaterial units with the simulation model, optimizing the layout mode of the elastic metamaterial based on the comparison result, and obtaining the optimal vibration control effect under the condition of small additional mass ratio, wherein a plurality of elastic metamaterial units are respectively arranged on key energy passage nodes when the floating substrate vibrates, and the key energy passage nodes are positioned above the flexible support.
For further explanation of the present solution, it is exemplified in connection with the accompanying drawings.
Example 1
In the present embodiment, two transducer units 2 are provided in an elastic metamaterial unit, for example, and will be described. Wherein, the side connector 22 in the vibrator unit 2 is made of rubber material, and the elastic metamaterial unit is obtained by the following steps:
step one: determining the shape and stiffness of the side attachment 22
The dimensions of the volume 21 are first determined on the basis of the additional mass requirements, then the vibrator resonance frequency of the elastic metamaterial unit is determined on the basis of the vibration reduction frequency bands, and finally the stiffness, material, size and shape of the side connection piece 22 are determined on the basis of the vibrator resonance frequency. In this embodiment, the side connector 22 may be adjusted and verified by finite element software.
Step two: determining overall dimensions and fabrication of elastic metamaterial units
And (3) determining the size of each structure in the shell 1 of the elastic metamaterial unit according to the parameters determined in the step one, and manufacturing and assembling after the processing diagram is obtained.
Step three: adjusting and determining the resonant frequency of the vibrator unit 2
And a damping structural member 3 is arranged between the two vibrator units 2, after the vibrator units 2 and the outer shell 1 are assembled, vibration test is carried out on the assembled metamaterial units, so that the vibrator resonance frequency of the actually manufactured elastic metamaterial unit is obtained, and the number of the frequency modulation structural members 23 is increased and decreased on the vibrator units 2 to adjust the vibrator resonance frequency, so that the ideal resonance frequency is obtained.
Step four: determining the layout of elastic metamaterial units
And modeling by utilizing finite element software aiming at the actual vibration condition of the structure to be damped, simulating the vibration response of the structure, comprehensively considering the path of vibration energy, and optimizing the layout mode of the elastic metamaterial unit to obtain the optimal damping scheme for the large-scale buoyant raft structure.
According to the design steps, vibrator units with various specific structures can be designed. Thus, the advantages of the present invention are detailed in connection with specific setup procedures.
In this embodiment, when the two vibrator units 2 are installed in the outer casing 1, the side connecting members 22 are respectively connected with the bearing side plates 12, so that the vertical mass 21 mainly forms a local resonance structure through the shear strain of the side connecting members 22, and compared with the extrusion strain of the side connecting members 22, the shear strain can more effectively utilize the damping effect of the material (rubber) of the side connecting members 22, thereby more effectively achieving the purpose of vibration suppression.
In the present embodiment, since the resonance frequencies of the vibrator units 2 are located at the upper and lower positions, vibration in the intermediate frequency band of the resonance frequencies of the upper and lower vibrator units 2 can be effectively suppressed by the damping effect of the damping structural member 3 by further providing the damping structural member 3 made of a rubber material between the two vibrator units 2, thereby achieving the purpose of broadband vibration reduction.
In the present embodiment, the three-dimensional mass 21 is made of steel, and is provided in a rectangular parallelepiped structure. The outer shell 1 is made of aluminum alloy materials.
In the present embodiment, the resonance frequency of the upper vibrator unit 2 is smaller than the resonance frequency of the lower vibrator unit 2.
In the present embodiment, the side connector 22 and the damping structure 3 are each made of nitrile rubber.
In order to illustrate the vibration suppression effect of the elastic metamaterial unit, the vibration suppression effect of the elastic metamaterial unit on a large floating structure is simulated based on the arrangement of the elastic metamaterial unit and finite element software, and the vibration response of the large floating structure before and after the elastic metamaterial unit is added and the vibration response of the large floating structure after the rubber material of the elastic metamaterial unit is replaced by a steel material are compared, so that the effectiveness of the elastic metamaterial unit is verified. Meanwhile, aiming at the characteristics of large-scale floating working conditions, the vibration energy passage is comprehensively considered, and the layout mode of the elastic metamaterial is optimized, so that the optimal vibration control effect is obtained under the condition of small additional mass ratio, the vibration response of the structure before and after optimization is compared, and the effectiveness of the vibration reduction design scheme is verified.
Specifically, a low-frequency vibration reduction of 50Hz-200Hz is taken as an example of a large floating structure, wherein the large floating structure is a cuboid, the length and the width are 5m, the height is 0.4m, and the material is steel. The bottom surface of the large floating structure has 14 small cuboids (i.e. flexible supports) of 0.3m×0.3m×0.1m, and the materials are rubber, and the Young's modulus is 11.2MPa, which are used for simulating an air bag to form the large floating structure, as shown in fig. 4.
For the large floating structure, the vibration reduction means based on the elastic metamaterial technology often face the following conditional constraints:
(1) The weight is small and the large-scale distributed arrangement cannot be completely realized.
(2) The spatial layout positions are limited, and ideal periodic arrangement cannot be realized.
(3) The mode is difficult to accurately predict, and the mode peak point cannot be prevented from being confirmed.
Therefore, based on the above-described large floating structure, the elastic metamaterial units used are structurally designed in combination with the foregoing steps, and in this embodiment, two kinds of elastic metamaterial units, namely, an elastic metamaterial unit (1) and an elastic metamaterial unit (2), are designed, 8 for each elastic metamaterial unit, in consideration of weight limitation. In the present embodiment, the shape and hardness of the side connector 22 made of rubber are different in the two elastic metamaterial units, and the rest of the structure is the same. Specifically, in the elastic metamaterial unit (1) and the elastic metamaterial unit (2), the upper three-dimensional mass block 21 is a rectangular solid steel mass block with the thickness of 0.287m×0.2m×0.244m, and the lower three-dimensional mass block 21 is a rectangular solid steel mass block with the thickness of 0.287m×0.2 m. In this embodiment, each of the three-dimensional mass blocks 21 is provided with a frequency modulation structure member 23, the frequency modulation structure member 23 is a rectangular plate body, the surface size of the frequency modulation structure member is the same as the surface size of the three-dimensional mass block 21 to be mounted, the thickness of the frequency modulation structure member is 1mm, and the adopted material is steel.
In the present embodiment, in the elastic metamaterial unit (1), the side connector 22 connected to the upper vertical mass 21 is a rectangular parallelepiped having a young's modulus of 10MPa (hardness of 50 degrees), the side connector 22 connected to the lower vertical mass 21 is a rectangular parallelepiped having a young's modulus of 0.2m×0.18m×0.008m, and the young's modulus is 25.5MPa (hardness of 70 degrees), so that the resonance frequency of the upper vibrator unit 2 is 50Hz and the resonance frequency of the lower vibrator unit 2 is 150Hz.
In the elastic metamaterial unit (2), the side connector 22 connected to the upper vertical mass 21 is a rectangular parallelepiped with a young's modulus of 10MPa (hardness of 50 degrees) of 0.244m×0.2m×0.008m, the side connector 22 connected to the lower vertical mass 21 is a rectangular parallelepiped with a young's modulus of 40MPa (hardness of 85 degrees), so that the resonance frequency of the upper vibrator unit 2 is 100Hz and the resonance frequency of the lower vibrator unit 2 is 200Hz.
In the present embodiment, in the elastic metamaterial unit (1) and the elastic metamaterial unit (2), the damping structural member 3 made of rubber is a rectangular parallelepiped of 0.287m×0.2m×0.01m, and the young's modulus is 3.6MPa (hardness is 30 degrees).
Here, the operating state of the large floating structure is set, in which the excitation position is 1mm as shown in fig. 4, and the excitation direction is vertically downward. And calculating the displacement of the upper surface of the air bag under different excitation frequencies to obtain the vibration response of the large floating structure, and analyzing the vibration reduction effect of the elastic metamaterial unit.
Based on the working state of the large floating structure, three conditions are considered to respectively carry out comparison verification:
(1) No elastic metamaterial unit (inelastic metamaterial unit) is installed;
(2) Mounting an elastic metamaterial unit (a normal elastic metamaterial unit);
(3) The elastic metamaterial unit is installed, and all rubber materials of the elastic metamaterial unit are replaced by steel materials (all-steel elastic metamaterial unit).
The elastic metamaterial units (1) and the elastic metamaterial units (2) are all arranged around the floating structure, and are initially arranged according to the layout mode of fig. 5, and vibration responses of the floating structure under three conditions are simulated, and the result is shown in fig. 6.
The vibration response of the floating structure at 50-200Hz after the installation of the metamaterial unit can be effectively inhibited by comparing the vibration response of the elastic metamaterial unit (1) with the vibration response of the elastic metamaterial unit (2), and the vibration of the metamaterial unit with the all-steel structure can not be effectively inhibited by comparing the vibration response of the metamaterial unit with the all-steel structure, but the vibration mode of the floating structure can be increased, so that the vibration inhibiting effect of the elastic metamaterial unit is not caused by weight increase.
For the elastic metamaterial unit, each vibrator unit 2 can generate multiple vibration modes at different frequencies, and the vibrator unit 2 above in the elastic metamaterial unit (1) is taken as an example, and the modes at different vibration frequencies are shown in fig. 7. As can be seen from fig. 7, the vibrator unit 2 of the metamaterial unit has a main mode in one vertical direction and modes in other directions. For the main mode in the vertical direction, strong coupling can be formed at the two resonance units using the coupling rubber (i.e., the damping structure 3), thereby enhancing the energy dissipation effect of damping, as shown in fig. 8 (a). Meanwhile, the torsional modes of the two vibrators can also form coupling vibration through coupling rubber, so that the resonant mode of the elastic metamaterial unit is increased, as shown in fig. 8 (b). Moreover, the torsional mode of the two resonance units can drive the shell to vibrate, and the floating structure is also provided with a vibration reduction effect, as shown in fig. 8 (c). As shown in fig. 9, the displacements of the respective vibrators of the metamaterial unit in the vertical direction (Z direction) are not equal to the total displacement thereof, and even significantly different. This means that not only the primary resonance mode of the vibrator is excited, but also the resonance modes of other frequencies. Different resonance modes can act in the pass frequency range, and the broadband high-efficiency effect is realized.
The legend to fig. 9: 50Hz, total displacement of vibrator unit 2 with Tota l-elastic metamaterial unit (1) located above; 50Hz, the Z-elastic metamaterial unit (1) is positioned above the vibrator unit (2) and is displaced in the vertical direction; 100Hz, total displacement of vibrator unit 2 with Tota l-elastic metamaterial unit (1) below; the displacement of the Z-elastic metamaterial unit (1) in the vertical direction of the vibrator unit 2 below at 100 Hz; 150Hz, total displacement of vibrator unit 2 with Tota l-elastic metamaterial unit (2) above; 50Hz, and the Z-elastic metamaterial unit (2) is positioned above the vibrator unit (2) and is displaced in the vertical direction.
The result preliminarily verifies the vibration reduction effect of the elastic metamaterial unit, and the vibration energy is comprehensively considered on the passage of the floating structure, so that the layout mode of the elastic metamaterial is optimized, and a complete vibration reduction scheme is obtained.
For this large floating structure, the energy input point is the vibration source and the energy output point is the vibration isolator, so the metamaterial unit is placed on the critical energy path node, which in this case is the vibration isolator mounting point of the floating structure (i.e. above the flexible support of the floating substrate). At the path nodes, the damping of the coupled resonance acts on broadband, and the antiresonance acting force acts on the matrix resonance, thereby maximizing the utilization of a limited number of metamaterial units. The distribution of the optimized elastic metamaterial units is shown in fig. 10. The vibrational response of the large floating structure before and after optimization is compared as shown in fig. 11. The result shows that optimizing the distribution of the elastic metamaterial units on the large floating structure can further strengthen the vibration suppression effect, and the effectiveness of the vibration reduction design scheme is verified.
The simulation shows that the elastic metamaterial constructed by the elastic metamaterial cell (namely the vibrator unit 2) designed according to the invention can realize the structure vibration suppression of a low-frequency broadband; optimizing the distribution of the elastic metamaterial units on the large floating structure can further enhance the vibration suppression effect.
The foregoing is merely exemplary of embodiments of the invention and, as regards devices and arrangements not explicitly described in this disclosure, it should be understood that this can be done by general purpose devices and methods known in the art.
The above description is only one embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An elastic metamaterial unit, comprising: an outer case (1), and a plurality of vibrator units (2) having different resonance frequencies provided in the outer case (1);
in the outer shell (1), a plurality of vibrator units (2) are sequentially arranged along the vertical direction, and the vibrator units (2) which are adjacent up and down are arranged at intervals;
the vibrator unit (2) includes: a rigid solid mass (21) and a flexible side connector (22);
the side connecting pieces (22) are respectively arranged on two opposite sides of the three-dimensional mass block (21), and the side connecting pieces (22) are connected with the outer shell (1).
2. Elastic metamaterial unit according to claim 1, wherein vertically adjacent vibrator units (2) are optionally connected by a damping structural member (3); the upper end and the lower end of the damping structural member (3) are respectively connected with the three-dimensional mass blocks (21) of the vibrator unit (2).
3. Elastic metamaterial unit according to claim 2, wherein the resonance frequency of the cubic mass (21) of each vibrator unit (2) is different in the vertical direction.
4. A resilient metamaterial unit according to claim 3, wherein the resonance frequency of the vibrator unit (2) is adjusted by changing the characteristic parameters of the side connectors (22), and wherein the three-dimensional mass (21) in the vibrator unit (2) is adapted to generate a plurality of low frequency resonance modes in three dimensions; wherein the characteristic parameter is at least one of hardness, shape and material.
5. The elastic metamaterial unit according to claim 4, wherein the vibrator unit (2) further comprises: a frequency modulation structural member (23);
the frequency modulation structural member (23) is detachably connected with the three-dimensional mass block (21), and the connection position of the frequency modulation structural member (23) and the three-dimensional mass block (21) is different from one side of the three-dimensional mass block (21) connected with the side connecting piece (22).
6. The elastic metamaterial unit according to claim 5, wherein the cubic mass (21) in the vibrator unit (2) can be provided as a cylinder, cuboid or prism;
the damping structural member (3) can be provided as a cylinder, a sphere, a cuboid or a prism.
7. The elastic metamaterial unit according to claim 6, wherein the side connectors (22) are made of an elastic material with a damping coefficient higher than 0.15;
the damping structural member (3) is made of an elastic material with a damping coefficient higher than 0.15.
8. Elastic metamaterial unit according to claim 7, wherein said outer housing (1) comprises: a base (11), a load-bearing side plate (12) provided on the base (11), a top plate (13) supported on the load-bearing side plate (12), and a package side plate (14) connected to the load-bearing side plate (12) and the top plate (13);
the bearing side plates (12) are detachably connected with the base (11), and the two bearing side plates (12) are symmetrically arranged;
the top plate (13) is detachably connected with the bearing side plate (12);
two packaging side plates (14) are symmetrically arranged;
the side connecting piece (22) of the vibrator unit (2) is connected with the side face of the bearing side plate (12).
9. Elastic metamaterial unit according to claim 8, wherein the distance between the two opposite load-bearing side plates (12) is adjustable for compressing or relaxing the side connectors (22).
10. A method of damping vibrations using an elastic metamaterial unit as claimed in any one of claims 1 to 9, comprising:
determining a target structure, and establishing a simulation model for the target structure; wherein the target structure is a floating structure comprising: a floating substrate and a flexible support for supporting the floating substrate;
adding a vibration response based on the simulation model, and arranging the elastic metamaterial unit on the simulation model and performing simulation; wherein, the anti-resonance acting force of the elastic metamaterial unit acts on the matrix resonance of the floating matrix, and the damping formed by coupling resonance acts on broadband vibration;
and (3) comparing the front-back vibration response of the elastic metamaterial unit with the simulation model, optimizing the layout mode of the elastic metamaterial based on the comparison result, and obtaining the optimal vibration control effect under the condition of small additional mass ratio, wherein a plurality of elastic metamaterial units are respectively arranged on key energy passage nodes when the floating substrate vibrates, and the key energy passage nodes are positioned above the flexible support.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310557456.7A CN116645943A (en) | 2023-05-17 | 2023-05-17 | Elastic metamaterial unit and vibration reduction method adopting same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310557456.7A CN116645943A (en) | 2023-05-17 | 2023-05-17 | Elastic metamaterial unit and vibration reduction method adopting same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116645943A true CN116645943A (en) | 2023-08-25 |
Family
ID=87639159
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310557456.7A Pending CN116645943A (en) | 2023-05-17 | 2023-05-17 | Elastic metamaterial unit and vibration reduction method adopting same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116645943A (en) |
-
2023
- 2023-05-17 CN CN202310557456.7A patent/CN116645943A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20210237394A1 (en) | Acoustic material structure and method for assembling same and acoustic radiation structure | |
| KR101777319B1 (en) | Self-tuned mass damper and system comprising the same | |
| US9631692B2 (en) | Vibration damping device | |
| CN107701635B (en) | Low-frequency broadband local resonance structure with super-damping characteristic | |
| WO2005005857A1 (en) | Dynamic vibration absorber and dynamic vibration absorbing device using the same | |
| CN109404478B (en) | Vibrator unit and nonlinear acoustic metamaterial cellular structure based on vibrator unit | |
| CN112356521A (en) | Low-frequency vibration-damping light metamaterial lattice structure and manufacturing method thereof | |
| RU2483971C2 (en) | Vibration and noise protection device for vessel power equipment | |
| JP5140795B2 (en) | Active sound insulation device, active sound insulation panel, and active sound insulation method | |
| US6286782B1 (en) | Apparatus and method for reducing vibrations of a structure particularly a helicopter | |
| CN113982183A (en) | Vibration reduction metamaterial lattice sandwich beam with adjustable forbidden band frequency | |
| CN116645943A (en) | Elastic metamaterial unit and vibration reduction method adopting same | |
| CN111833837B (en) | Adjustable single-stage multi-band gap acoustic metamaterial structure and adjusting method | |
| WO2021215079A1 (en) | Vibration damping and sound insulating device | |
| Sun et al. | Vibrational power-flow analysis of a MIMO system using the transmission matrix approach | |
| CN112009619B (en) | Tuning particle damping type floating raft | |
| CN112392164A (en) | Sound insulation vibration reduction structure | |
| KR101951772B1 (en) | Generator with vibration isolation and anti-resonance function | |
| Kalderon et al. | A meta-structure for low-frequency acoustic treatment based on a KDamper-inertial amplification concept | |
| Que et al. | Tunable low frequency band gaps and sound transmission loss of a lever-type metamaterial plate | |
| CN221149647U (en) | Phonon unit cell and phonon crystal | |
| KR101301349B1 (en) | Dynamic Absorber | |
| CN219644043U (en) | Concatemer stereo set damping device and stereo set | |
| CN217460101U (en) | Vibration absorbing device | |
| JP4623513B2 (en) | Sound insulation base structure of face material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |