Acoustic Transmission Member and Method of Designing Same
AssigneeThe Yokohama Rubber Co., Ltd.
InventorsMasato Tadokoro, Yusuke Tanaka
Life of this patent
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Abstract
The present technology provides an acoustic transmission member that includes a core layer layered between two skin layers, the skin layers being formed of a material having a higher elastic modulus than a material of the core layer. A thickness ds of the skin layers is formed such that Equation (1) is satisfied, where f is the center frequency of the transmission frequency band, cw is the acoustic velocity in the medium surrounding the acoustic transmission member, λ is the wavelength corresponding to the center frequency in the medium, Cds is the longitudinal wave acoustic velocity in the skin layer, and n is a discretionary natural number. ds = n 2 Cds cw λ = n 2 Cds f ( 1 )
Claims15
An acoustic transmission member with a planar shape having a predetermined acoustic frequency band as a transmission frequency band, the acoustic transmission member comprising:
- a core layer layered between two skin layers,
- wherein the skin layers are formed of a material having a higher elastic modulus than a material of the core layer;
- a thickness ds of the skin layers satisfies Equation (1),
- where f is a center frequency of the transmission frequency band, cw is an acoustic velocity in a medium surrounding the acoustic transmission member, λ is a wavelength corresponding to the center frequency in the medium, Cds is a longitudinal wave acoustic velocity in the skin layers, and n is a discretionary natural number;
- ds
- =
- n
- 2
-
-
- Cds
- cw
-
- λ
- =
- n
- 2
-
-
- Cds
- f
- .
- (
- 1
- )
A method of designing an acoustic transmission member, the acoustic transmission member having a planar shape, including a core layer layered between two skin layers, and having a first acoustic frequency band as a transmission frequency band and a second acoustic frequency band as a shielded frequency band, the method comprising:
- a skin layer thickness determining step of determining a thickness ds of the skin layers using Equation (1);
- a transmission loss measuring step of measuring or calculating transmission losses of each layer formed by layering a core layer, having varied thickness, successively on the skin layers with a thickness determined in the skin layer thickness determining step;
- and
- a core layer thickness determining step of determining a thickness of a core layer with a maximal value of transmission loss, among the transmission losses measured or calculated, being closest to a center frequency of a shielded frequency band as a thickness of the core layer of the acoustic transmission member,
- where in Equation (1), f is a center frequency of the transmission frequency band, cw is an acoustic velocity in a medium surrounding the acoustic transmission member, λ is a wavelength corresponding to the center frequency in the medium, Cds is a longitudinal wave acoustic velocity in the skin layers, and n is a discretionary natural number;
- ds
- =
- n
- 2
-
-
- Cds
- cw
-
- λ
- =
- n
- 2
-
-
- Cds
- f
- .
- (
- 1
- )
A method of designing an acoustic transmission member, the acoustic transmission member having a planar shape, including a core layer layered between two skin layers, having a predetermined acoustic frequency band as a transmission frequency band, and a predetermined required strength and rigidity, the method comprising:
- a skin layer thickness determining step of determining a thickness ds of the skin layers using Equation (1);
- and
- a core layer thickness determining step of calculating a thickness of the core layer having strength satisfying the required strength and rigidity when layered between the skin layers with a thickness determined in the skin layer thickness determining step
- where in Equation (1), f is a center frequency of the transmission frequency band, cw is an acoustic velocity in a medium surrounding the acoustic transmission member, λ is a wavelength corresponding to the center frequency in the medium, Cds is a longitudinal wave acoustic velocity in the skin layers, and n is a discretionary natural number;
- ds
- =
- n
- 2
-
-
- Cds
- cw
-
- λ
- =
- n
- 2
-
-
- Cds
- f
- .
- (
- 1
- )
Dependencies are inferred from the claim text.