Acoustic metamaterial units with the function of soundproof, flow passing and heat; transfer enhancement, the composite structure and the preparation methods thereof
The present invention relates to the acoustic metamaterial structural unit with the function of soundproof, flow-passing and heat-transferring enhancement, which comprises a frame, a constraint placed in the frame and a piece of membrane covering at least one surface of the frame; both the frame and the membrane are respectively placed at least one hole. Besides, the present invention also provides the acoustic metamaterial composite plate and the composite structure constructed with the acoustic metamaterial structural unit; the method for adjusting the frequency and the assemble method. The present structural unit possesses better soundproof property than the routine perforated plated or micro-perforated plate in broad operating frequency. And also the enough heat flow, gas flow or fluid flow can pass through smoothly. The diffuse efficiency of the heat energy of the mediums on both sides of the hole is increased by the vibration of the self-structure under the excitation of the soundwave and further the efficiency of heat exchange is accelerated. The method for assembling the acoustic metamaterial composite structure with the acoustic metamaterial structural units is simple. The operation performance is steady.
1. An acoustic metamaterial structural unit, comprising:
a frame, the frame having a first member and a second member, the second member opposite the first member;
a constraint placed within the frame and rigidly connected to the first and the second members of the frame, the constraint having at least one hole; and
a flexible membrane covering at least one surface of the frame, the membrane having at least one hole and constrained by the constraint.
2. The acoustic metamaterial structural unit according to, wherein a shape, position, and size of the at least one hole in the constraint are the same as a shape, position, and size of the at least one hole in the membrane.
3. The acoustic metamaterial structural unit according to claim 2 , wherein the size of the at least one hole in the constraint is determined by a flow rate passing through the at least one hole and by a soundproof operating frequency bond.
4. The acoustic metamaterial structural unit according to claim 3 , wherein the shape of the at least one hole in the constraint is a regular symmetric geometry.
5. The acoustic metamaterial structural unit according to claim 1 , wherein both a top and a bottom surfaces of the frame are covered by the.
6. The acoustic metamaterial structural unit according to claim 5 , wherein a porous materials is filled within a space between the top and bottom surfaces of the frame covered by the membrane.
7. The acoustic metamaterial structural unit according to claim 1 , wherein a shape of the frame is square or hexagon.
8. The acoustic metamaterial structural unit according to claim 1 , wherein the constraint constrains the membrane by a linear contact, wherein the contact is regular symmetric geometry having a spherical, square or regular polygon shape.
9. The acoustic metamaterial structural unit according to claim 1 , wherein a material of the frame and the constraint is selected from the list consisting of aluminum, steel, wood, rubber, plastic, glass, gypsum, cement, high molecular polymer and composite fiber.
10. An acoustic metamaterial plates structure constructed by the said acoustic metamaterial structural unit according to claim 1 .
11. The acoustic metamaterial plates structure according to claim 10 , wherein the acoustic metamaterial plates structure is combined and spliced in an inner plane direction by the acoustic metamaterial structural unit.
12. An acoustic metamaterial composite structure constructed by the acoustic metamaterial plates structure according to claim 10 .
13. The acoustic metamaterial composite structure according to claim 12 , wherein the acoustic metamaterial composite structure is stacked in layers, in an outer vertical direction of the acoustic metamaterial plates structure.
14. The acoustic metamaterial composite structure according to claim 13 , wherein a space formed by the layers of the acoustic metamaterial plates structure is filled with a porous material.
15. A method for adjusting at least one operating frequency band of the acoustic metamaterial structural unit according to any of the claims 1 - 9 , the method comprising the steps of:
adjusting the sizes and materials of the frame, the constraint and the membrane so as to adjust the at least one operating frequency band.
16. A method for assembling the acoustic metamaterial structural unit according to any of the claims 1 - 9 , characterized that the perforated constraint and the frames are prepared by the integral forming process. The perforated constraint and the frames are prepared as prefabrications firstly, and then the prefabrication of the perforated constraint is rigidly connected with the frame prefabrication to form the unit frame structure. The membrane is covered the unit frame structure under the freely spreading conditions, and further they are rigidly contacted. Finally, the membrane is perforated. Preferably, the integral forming process is milling, casting, stamping, laser cutting or the 3D printing process. Preferably, the prefabrication of the perforated constraint and frame are prepared by the process of milling, casting, stamping, laser cutting or the 3D printing. Preferably, the rigid connection is gluing connection, hot weld connection or mechanical rivet connection.
17. A method for assembling the acoustic metamaterial plates according to claim 11 , characterized in that the assembled acoustic metamaterial structural units are rigidly connected, or the assembled acoustic metamaterial structural units are combined with wedge connector to form the acoustic metamaterial plate with a certain curvature. The perforated constraint and the frames are prepared to be the whole the acoustic metamaterial frame structure by the integral forming process. The membrane is covered the unit frame structure under the freely spreading conditions, and further they are rigidly contacted. Finally, the membrane is perforated. In this case, the sizes and the thickness of the membrane for every acoustic metamaterial structural unit are same. Preferably, the unit structure unit or the whole acoustic metamaterial plate is prepared by integral forming process such as milling, casting, stamping, laser cutting or the 3D printing process. Preferably, the prefabrication of the perforated constraint and frame are prepared by the process of milling, casting, stamping, laser cutting or the 3D printing. Preferably, the rigid connection is gluing connection, hot weld connection or mechanical rivet connection.
18. A method for assembling the acoustic metamaterial composite structure according to claim 14 , the porous material is made into small units, and further filled into the space formed by the frame and the constraint of the acoustic metamaterial structural unit. In the meanwhile, a whole piece of routine acoustic material plate is perforated in advance, or the whole piece of routine acoustic metamaterial plate is coordinately perforated with the said acoustic metamaterial plate. And then, they are contacted with each other and rigidly connected. Preferably, the porous material is made into small units by the constructing model, clipping or stamping. Preferably, the routine acoustic material plate directly contacts the acoustic metamaterial plate, they are contacted by supporting with the elastic cushion, so as to isolate the vibration delivery between the different acoustic material plates. Preferably, the rigid connection is gluing connection, hot weld connection or mechanical rivet connection.