CN210109814U - Honeycomb structure with adjustable sound absorption performance - Google Patents
Honeycomb structure with adjustable sound absorption performance Download PDFInfo
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- CN210109814U CN210109814U CN201921474459.XU CN201921474459U CN210109814U CN 210109814 U CN210109814 U CN 210109814U CN 201921474459 U CN201921474459 U CN 201921474459U CN 210109814 U CN210109814 U CN 210109814U
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Abstract
The utility model discloses a honeycomb of adjustable sound absorption performance has been designed based on combined material honeycomb panel structure, including top surface board and lower surface board and the honeycomb core of clamp between top surface board and lower surface board, the inside in-core microperforated panel that is provided with of honeycomb core, be equipped with the hole of a plurality of sound absorptions on the in-core microperforated panel, in-core microperforated panel upper surface one end is fixed with a fixed plate, fixed plate central symmetry installs two fixed one end's SMP actuating arms that send electricity, an adjustable sound absorption baffle is respectively installed to the free end of SMP actuating arm that sends electricity, SMP actuating arm is sent electricity by the lead wire and external control circuit links to each other, the rotation angle of SMP actuating arm is sent electricity through the voltage U of adjusting external control circuit output, thereby the hole number of sound absorption on the microp. The utility model relates to a method principle is simple, only needs to add this structure in traditional honeycomb structure part just can play the characteristics of adjustable sound absorption peak value, and the practicality is strong, easy operation popularization.
Description
Technical Field
The utility model belongs to a low noise design method of honeycomb structure design, in particular to honeycomb structure of adjustable sound absorption performance.
Background
The honeycomb sandwich structure is a common engineering structure with sound insulation characteristic and good mechanical property. The traditional honeycomb sandwich structure generally uses additionally added porous materials to play a sound absorption purpose in order to achieve the sound absorption and insulation integrated design, and the porous sound absorption materials have overlarge structural weight and can bring additional adverse effects to the fields of aviation and buildings. Therefore, the method for researching the low-noise design of the honeycomb sandwich structure on the premise of keeping the light weight has great significance for the research of vibration and noise reduction of the honeycomb sandwich composite plate structure. The conventional hexagonal honeycomb sandwich panel structure (as shown in fig. 1) is formed by combining an upper surface plate 1 and a lower surface plate 2 with a honeycomb core 9 sandwiched therebetween.
In recent years, many researchers have conducted intensive studies on improvement of sound insulation and absorption integration of honeycomb sandwich structures, and among them, application of a sound absorber having a micro-perforated plate to a honeycomb structure is effective as a means for imparting sound absorption to a honeycomb structure while keeping the structure light in weight. According to the sound absorption principle of the micro-perforated plate, the hole diameter, the plate thickness, the perforation rate and the cavity depth of the micro-perforated plate structure can affect the sound absorption performance of the structure, namely the sound absorption coefficient and the sound absorption peak frequency. The existing structure is generally characterized in that a micro-perforated plate structure is added in a honeycomb structure, so that the whole structure is endowed with fixed sound absorption performance, and a good aiming effect cannot be achieved on an external variable noise environment.
Shape Memory Polymer (SMP) is a new type functional high molecular material, and compared with traditional shape memory alloy, it has the advantages of light weight, large recoverable deformation, easy processing, low cost, easy regulation of deformation response temperature, etc. The driving arm is made of the electro SMP composite material, and a certain voltage is applied to the driving arm to deform the driving arm, so that the adjustable perforation rate baffle connected with the driving arm is driven, the perforation rate of the micro-perforated plate is changed, and finally the purpose of adjusting the sound absorption frequency can be achieved.
Therefore, under the condition that the overall layout of the hexagonal honeycomb-micro perforated composite structure is not changed, the perforation rate of the micro perforated plate can be changed directly by changing the control voltage, and further the adjustable sound absorption frequency of the hexagonal honeycomb-micro perforated composite plate structure can be realized, so that the noise is effectively controlled.
SUMMERY OF THE UTILITY MODEL
The utility model discloses receive top-down's the perpendicular excitation condition to honeycomb-microperforated panel composite construction, the design uses the actuating arm that a neotype electricity induced SMP combined material made, electricity induced SMP actuating arm keeps external force and then "freezes" partial stress and deformation through the back that heaies up in advance, then install on the fixed plate, through material electricity induced heat release "freeze" stress and deformation, come the drive to install the baffle at the actuating arm another, reach the purpose of adjusting the hole number that microperforated panel participated in the sound absorption, thereby make the perforation rate change, the change of perforation rate has played the effect of adjusting structure sound absorption performance.
The utility model provides a technical problem adopt following technical scheme.
The utility model provides an adjustable sound absorption performance's honeycomb structure, includes upper surface plate and lower surface plate and presss from both sides the honeycomb core between upper surface plate and lower surface plate, honeycomb core inside is provided with the in-core microperforated panel, is equipped with the hole of a plurality of sound absorptions on the in-core microperforated panel, and in-core microperforated panel upper surface one end is fixed with a fixed plate, and fixed plate central symmetry installs two fixed end's electric SMP actuating arm, and an adjustable sound absorption baffle is respectively installed to the free end of electric SMP actuating arm, and electric SMP actuating arm links to each other with external control circuit by the lead wire, controls the rotation angle of electric SMP actuating arm through adjusting the voltage U of external control circuit output to control adjustable sound absorption baffle and adjust the hole number of sound.
Preferably, the honeycomb core is a hexagonal honeycomb structure.
Preferably, the sound absorbing holes in the microperforated panel in the core are arranged in equally spaced triangles.
Preferably, the upper surface plate is provided with a plurality of sound absorption holes.
Preferably, the sound-absorbing holes of the upper surface plate are arranged in a triangular shape at equal intervals.
A honeycomb sandwich plate is formed by combining an upper surface plate, a lower surface plate and a honeycomb core clamped between the upper surface plate and the lower surface plate, and is characterized in that a core-in micro-perforated plate is arranged in the honeycomb core, one end of the upper surface of the core-in micro-perforated plate is fixedly provided with a fixed plate, the center of the fixed plate is symmetrically provided with two electric SMP driving arms with one fixed end, the free ends of the electric SMP driving arms are respectively provided with an adjustable sound absorption baffle, and the driving arms are connected with an external control circuit through leads; the design steps are as follows:
1) in order to enable the structure to have better sound absorption performance, the upper surface plate uses a micro-perforated plate and a core micro-perforated plate to form a double-layer micro-perforated plate structure, and the theoretical calculation formula of the micro-perforated plate is set as follows:
zi＝ri+iωmi(1)
wherein r isiRelative acoustic resistance of the i-th microperforated panel, miIs the relative acoustic mass, t, of the i-th microperforated paneliThickness of the i-th microperforated plate, diIs the perforation diameter, p, of the i-th microperforated paneliIs the percentage of the perforated area of the i-th microperforated panel to the total panel area, kiConstant of the perforated plate of the ith micro-perforated plate, mu is the kinematic viscosity coefficient of air, rho is the air density, c is the sound velocity in the air at normal temperature, f0Is the sound frequency, ω is the sound circle frequency. Wherein the subscript corresponding to the upper surface plate is 1 and the subscript corresponding to the micro-perforated plate in the core is 2.
The specific acoustic impedance of the microperforated panel calculated by a transfer matrix method is as follows:
the transfer matrix of the microperforated panel is:
while the transfer matrix for the cavity portion is:
wherein DiFor the cavity thickness behind the ith layer of microperforated panel, consider the double-deck microperforated panel structure, then overall structure's transfer matrix is:
the overall relative acoustic impedance of the double-layer microperforated panel is then:
obtaining a structural sound absorption coefficient:
the sound absorption coefficient when the sound absorption structure resonates to obtain the maximum sound absorption peak is as follows:
from the above theoretical formula, as the perforation rate p decreases, the relative acoustic resistance r and the relative acoustic mass m increase, and the relative acoustic impedance ratio z of the corresponding structure increasestotalIncreased, maximum sound absorption coefficient α0With a consequent decrease, i.e. absorption of the peak frequency directionLow frequency drift;
2) α based on the sound absorption coefficient0Along with the change rule of the perforation rate p, a honeycomb structure capable of adjusting the sound absorption performance is designed, and the purpose of adjusting the perforation aperture and the perforation rate is achieved through the deformation generated by the voltage applied to the electric SMP driving arm; wherein, the perforation rate can be obtained by the calculation formula of the perforation rate when the microperforated plates are densely arranged, namely, arranged in a triangle:
in the formula, B is the hole spacing, and the specific distribution position parameters of the obtained through holes are calculated to facilitate the design of the baffle;
3) theoretical calculation is carried out according to the formulas (2), (3), (4) and (11), when the diameter d of the small hole is 0.5mm and the thickness t of the board is 0.5mm, the maximum sound absorption coefficient of the micro-perforated plate in medium and low frequencies can be kept above 0.5 when the calculation result shows that the perforation rate is below 5.5%, and because the calculation only considers the maximum sound absorption coefficient, a model with lower perforation rate is correspondingly selected in the actual design so as to enable the bandwidth when the sound absorption coefficient is 0.5 to be wider, and the design is carried out according to the principle.
The utility model discloses compare honeycomb panel in the past, have following advantage: the honeycomb plate can adjust the absorption peak value of the honeycomb plate for medium and low frequency noise according to the requirements of specific scenes so as to achieve the optimal noise reduction effect; the voltage is used as a control signal, so that more mechanical control elements can be reduced, and the light property of the honeycomb plate is maintained; the honeycomb plate can be mixed with a common honeycomb plate in a unit form, and the engineering manufacture is easy to realize; under the condition that one plate is multipurpose, the light weight characteristic of the cellular board is kept, and the cellular board has a very wide application prospect in aerospace.
Drawings
FIG. 1 is a schematic view of a conventional hexagonal honeycomb sandwich panel construction;
FIG. 2 is a schematic view of the honeycomb sandwich structure of the present invention with micro-perforated holes on the top panel;
FIG. 3 is a longitudinal cross-sectional view of a honeycomb core of the present invention;
fig. 4 is a top view of an embodiment of the present invention;
FIG. 5 is a schematic plan view of a microperforated panel in the core of the present invention;
fig. 6a is a schematic structural diagram of the fixing plate of the present invention.
Figure 6b is a schematic diagram of the structure of an electro-SMP actuator arm according to the present invention.
Fig. 6c is a schematic structural view of the adjustable sound-absorbing baffle of the present invention.
Fig. 6d is an assembly initial state diagram of the micro-perforated plate with adjustable sound absorption frequency according to the present invention.
FIG. 7 shows that the micro-perforated plate with adjustable sound absorption frequency of the utility model is loaded with voltage U1State diagram of time.
FIG. 8 shows the utility model discloses a well adjustable sound absorption frequency microperforated panel is loading voltage U2State diagram of time.
Fig. 9 is a diagram of a result of simulation calculation according to an embodiment of the present invention.
In the figure: 1. the honeycomb core comprises an upper surface plate, a lower surface plate, a core inner micro-perforated plate, a fixing plate, an electric SMP driving arm, an adjustable sound absorption baffle, a lead wire, an external control circuit and a honeycomb core, wherein the upper surface plate is 2, the lower surface plate is 3, the core inner micro-perforated plate is 4, the fixing plate is 5, the electric SMP driving arm is 6, the adjustable sound absorption baffle is 6.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings. See fig. 2-9.
The utility model discloses a obtain the better sound absorption characteristic of honeycomb sandwich structure, consider to make into the microperforated panel with the top surface board, as shown in figure 2.
A honeycomb core 9 is taken out from the honeycomb sandwich structure shown in FIG. 2, a core-in-core micro-perforated plate 3 shown in FIG. 5 is added in the honeycomb core 9, a fixed plate 4 shown in FIG. 6a is closely mounted on one side of the surface of the core-in-core micro-perforated plate 3, two symmetrically distributed electrically actuated SMP driving arms 5 shown in FIG. 6b are mounted in the center of the fixed plate, and adjustable sound absorption baffles 6 shown in FIG. 6c are symmetrically mounted at the free ends of the driving arms respectively. The electro-SMP drive arm 5 is connected to an external control circuit 8 using leads 7.
Example (b): 7 honeycomb cores connected in the hexagonal honeycomb plate are taken out as the calculation domain of the embodiment, and the top view of the embodiment is shown in FIG. 4, and the side view of the embodiment is shown in FIG. 3. Wherein the honeycomb core 9 has the following dimensions: the honeycomb core side is 6mm, the height is 60mm, and the thickness is 0.43 mm; the upper surface 1 is a microperforated plate with a hole diameter of 0.5mm, a perforation rate of 3% and a plate thickness of 0.5mm, and the lower surface 2 is a thin plate with a plate thickness of 1 mm; in the embodiment, only a single honeycomb core 9 is arranged at the center, and a micro-perforated plate with adjustable sound absorption frequency, which is formed by a micro-perforated plate 3 in the core, a fixed plate 4, an electrically actuated SMP driving arm 5 and an adjustable sound absorption baffle 6, an external lead 7 and an external control circuit 8 are added, as shown in FIG. 6 d.
During simulation, the hexagonal honeycomb sandwich structure is stably placed at the bottommost end of an solved domain, and a background cavity is arranged above the hexagonal honeycomb structure to calculate the sound absorption coefficient.
Wherein fig. 5 is the in-core micro-perforated plate 3 fixed in the hexagonal honeycomb core 9, in fig. 5, the perforation diameter d is 0.5mm, the hole pitch B is 2.5mm, the side length R of the regular hexagonal honeycomb core is 6mm, the initial perforation rate of the in-core micro-perforated plate 3 is 3.99%, and the perforation number is 19.
Adding a fixed plate 4 as shown in figure 6(a) on the micro-perforated plate 3 in the core, wherein a is 1.65mm, b is 6.00mm, fixing two segments of symmetrical electric SMP driving arms 5 with the length of l being 1.93mm as shown in figure 6(b) at the midpoint of the surface of the fixed plate 4, symmetrically connecting a baffle 6 with adjustable perforation rate as shown in figure 6(c) at the free end of the driving arms, wherein l is0＝3.99mm，l1＝4.09mm， l2＝1.30mm，l3＝3.96mm，l4＝2.58mm，l5＝1.26mm。
Fig. 6d is a top view of the initial state when the fixing plate 4, the electro SMP driving arm 5, and the adjustable perforation rate baffle 6 are mounted on the in-core micro perforated plate 3, at this time, the number of holes participating in sound absorption is 10, and the corresponding perforation rate is 2.10%.
The drive arm 5 of the electro SMP is connected with an external control circuit 8 by a lead 7 and outputs a certain voltage U1Then, the electric SMP driving arm 5 generates deformation in the plane of the adjustable sound absorption baffle 6 to drive the adjustable sound absorption baffle 6 to rotate inwards by 12 degrees, at this time, the structural state is as shown in FIG. 7, the number of holes actually participating in sound absorption is changed into 16, and the corresponding through holes are perforatedThe rate became 3.36%; when the output voltage of the external control circuit 8 is U2Meanwhile, the electric SMP driving arm 5 continuously generates deformation and simultaneously drives the adjustable sound absorption baffle 6 to continuously rotate inwards by 9 degrees, at the moment, the structural state is as shown in figure 8, the number of holes actually participating in sound absorption is 12, and the corresponding perforation rate is 2.52 percent.
The sound absorption coefficient obtained by simulating the above embodiment by using numerical simulation software COMSOL is shown in fig. 9. When the perforated plate with the adjustable sound absorption frequency is added to the single honeycomb core in the center, the sound absorption coefficient of the structure has an absorption peak at 890Hz, the absorption peak mainly comes from the sound absorption effect of the upper surface micro perforated plate, when the perforation rate is reduced, the absorption peak brought by the micro perforated plate with the adjustable sound absorption frequency is changed from 2430Hz to 2270Hz, and finally the absorption peak moves to 2170Hz towards low frequency, so that the theoretical result is met, and the frequency drift of the sound absorption peak is up to 260 Hz. Meanwhile, along with the approach of the absorption peak brought by the upper surface micro-perforated plate and the absorption peak brought by the adjustable sound absorption frequency micro-perforated plate, the sound absorption performance of the structure in the frequency range between the two absorption peaks is also remarkably improved.
Therefore, the utility model discloses, can make hexagon honeycomb-microperforated panel structure realize adjustable sound absorption frequency to effective control noise.
The above description is only an example of the preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and those skilled in the art should be able to realize the equivalent alternatives and obvious variations of the present invention.
Claims (5)
1. A honeycomb structure with adjustable sound absorption performance comprises an upper surface plate (1), a lower surface plate (2) and a honeycomb core (9) clamped between the upper surface plate (1) and the lower surface plate (2), and is characterized in that a core-in micro-perforated plate (3) is arranged inside the honeycomb core (9), a plurality of sound absorption holes are formed in the core-in micro-perforated plate (3), a fixing plate (4) is fixed at one end of the upper surface of the core-in micro-perforated plate (3), two electric induced SMP driving arms (5) with one fixed end are symmetrically installed in the center of the fixing plate (4), adjustable sound absorption baffles (6) are respectively installed at the free ends of the electric induced SMP driving arms (5), the electric induced SMP driving arms (5) are connected with an external control circuit (8) through leads (7), and the rotation angle of the electric induced SMP driving arms (5) is controlled by adjusting voltage U output by the external control circuit, thereby controlling the adjustable sound absorption baffle (6) to adjust the number of sound absorption holes on the micro-perforated plate (3) in the core.
2. The adjustable sound absorption honeycomb of claim 1 wherein the honeycomb core (9) is a hexagonal honeycomb structure.
3. The honeycomb structure with adjustable sound absorption properties according to claim 1, characterized in that the sound absorbing holes on the core microperforated panel (3) are arranged in equally spaced triangles.
4. The honeycomb structure with adjustable sound absorption properties according to claim 1, characterized in that the upper surface panel (1) is provided with sound absorbing holes.
5. The honeycomb structure with adjustable sound absorption performance according to claim 4, characterized in that the holes for sound absorption on the upper surface panel (1) are arranged in a triangular shape at equal intervals.
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| CN201921474459.XU CN210109814U (en) | 2019-09-05 | 2019-09-05 | Honeycomb structure with adjustable sound absorption performance |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110427731A (en) * | 2019-09-05 | 2019-11-08 | 南昌航空大学 | A kind of honeycomb and its design method of adjustable sound absorbing performance |
| WO2022016684A1 (en) * | 2020-07-24 | 2022-01-27 | 株洲国创轨道科技有限公司 | Sound absorbing panel |
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2019
- 2019-09-05 CN CN201921474459.XU patent/CN210109814U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110427731A (en) * | 2019-09-05 | 2019-11-08 | 南昌航空大学 | A kind of honeycomb and its design method of adjustable sound absorbing performance |
| WO2022016684A1 (en) * | 2020-07-24 | 2022-01-27 | 株洲国创轨道科技有限公司 | Sound absorbing panel |
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