Soundproof structure
Provided is a soundproof structure with a small size and high soundproofing performance of a low frequency band. The soundproof structure includes at least one soundproof cell which includes a frame having a hole portion, an elastic layer laminated on a frame of one opening surface of the frame, and a film laminated on the elastic layer so as to cover the hole portion. An effective displacement amount at a position at which an amplitude is maximized in a region bonded to the elastic layer in a case where a film vibration of the film occurs is 0.4% to 10% of an effective displacement amount at a position at which an amplitude of the film is maximized.
1. A soundproof structure comprising:
at least one soundproof cell including
a frame having a hole portion,
an elastic layer laminated on a frame of an opening surface of the frame, and
a film laminated on the elastic layer so as to cover the hole portion,
wherein an effective displacement amount at a position at which an amplitude is maximized in a region bonded to the elastic layer in a case where a film vibration of the film occurs is 0.4% to 10% of an effective displacement amount at a position at which an amplitude of the film is maximized.
2. The soundproof structure according to claim 1 ,
wherein the elastic layer is an adhesive layer which bonds the frame and the film.
3. The soundproof structure according to claim 1 ,
wherein, in a case where a thickness of the elastic layer is t and an effective modulus of elasticity of the elastic layer in a thickness direction is E eff , a composite parameter σ=t 1.4 ×(1+1/E eff ) satisfies 3.0×10 −2 <σ<5×10 1 .
4. The soundproof structure according to claim 2 ,
wherein, in a case where a thickness of the elastic layer is t and an effective modulus of elasticity of the elastic layer in a thickness direction is E eff , a composite parameter σ=t 1.4 ×(1+1/E eff ) satisfies 3.0×10 −2 <σ<5×10 1 .
5. The soundproof structure according to claim 3 ,
wherein the elastic layer is a single layer, and
the effective modulus of elasticity E eff of the elastic layer in the thickness direction is Young's modulus E young (GPa) of a material of the elastic layer.
6. The soundproof structure according to claim 4 ,
wherein the elastic layer is a single layer, and
the effective modulus of elasticity E eff of the elastic layer in the thickness direction is Young's modulus E young (GPa) of a material of the elastic layer.
7. The soundproof structure according to claim 3 ,
wherein the elastic layer includes a plurality of layers, and
in a case where an indentation modulus of elasticity of the elastic layer is E ind , the number of layers is N, and an average thickness of the layers is t, the effective modulus of elasticity E eff of the elastic layer in the thickness direction is E eff =E ind /{(t/100) 3 ×N 5 }.
8. The soundproof structure according to claim 4 ,
wherein the elastic layer includes a plurality of layers, and
in a case where an indentation modulus of elasticity of the elastic layer is E ind , the number of layers is N, and an average thickness of the layers is t, the effective modulus of elasticity E eff of the elastic layer in the thickness direction is E eff =E ind /{(t/100) 3 ×N 5 }.
9. The soundproof structure according to claim 1 ,
wherein the soundproof cell is smaller than a wavelength of a first natural vibration frequency of the film vibration of the film.
10. The soundproof structure according to claim 6 ,
wherein the soundproof cell is smaller than a wavelength of a first natural vibration frequency of the film vibration of the film.
11. The soundproof structure according to claim 8 ,
wherein the soundproof cell is smaller than a wavelength of a first natural vibration frequency of the film vibration of the film.
12. The soundproof structure according to claim 9 ,
wherein the first natural vibration frequency is 100000 Hz or less.
13. The soundproof structure according to claim 10 ,
wherein the first natural vibration frequency is 100000 Hz or less.
14. The soundproof structure according to claim 11 ,
wherein the first natural vibration frequency is 100000 Hz or less.