Estimation method for structure low-frequency radiation sound power under vibration distributed undersampling condition

A radiated sound and under-sampling technology, which is used in the measurement of ultrasonic/sonic/infrasonic waves, measuring devices, instruments, etc., can solve the problem of estimating radiated sound power without sound radiation mode, etc., and achieve the effect of accurate sound power

Inactive Publication Date: 2013-09-18
NANJING UNIV
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Problems solved by technology

[0006] There is currently no method for estimating the radiated sou

Method used

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  • Estimation method for structure low-frequency radiation sound power under vibration distributed undersampling condition
  • Estimation method for structure low-frequency radiation sound power under vibration distributed undersampling condition
  • Estimation method for structure low-frequency radiation sound power under vibration distributed undersampling condition

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Experimental program
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Embodiment 1

[0027] Step 1. Measure the geometric size and shape of the structure:

[0028] Taking the infinite rigid baffle with a length, width and height of 0.6m×0.42m×0.001m simply supported aluminum plate as the calculation model, the Young's modulus is 6.85×10 10 N / m 2 , The density is 2700Kg / m 3 , Poisson’s ratio is 0.3, and the damping coefficient of the vibration mode is 0.01. The plane where the board is located is the coordinate plane, the lower left corner of the board is the origin of the coordinates, the long side is the x axis, and the short side is the y axis. The coordinates of the four vertices are (0, 0), (0.6, 0), (0.6, 0.42) ), (0, 0.42). In order to be able to excite enough vibration modes, a point force source with an amplitude of 1000N acts vertically at (0.03, 0.021);

[0029] Step 2: Divide the rectangular board into 3×7 small units, such as figure 1 21 areas composed of solid lines, where the circles represent sampling points, and the horizontal sampling interval is...

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Abstract

The invention provides an estimation method for a structure low-frequency radiation sound power under a vibration distributed undersampling condition. The method comprises the steps of (1) measuring the geometric size and shape of a structure; (2), distributing a plurality of vibration speed sensors on the structure surface to obtain the normal velocity of a limited point at the structure surface; (3), computing a structural radiation modal and the accompanying coefficient of each order of radiation modal; (4), performing interpolation on the structure surface normal velocity based on the sound radiation modal; (5), obtaining the accompany coefficient of the radiation modal after the interpolation; and (6) estimating the radiation sound power. The method based on the structure sound radiation modal obtains the vibration speed of the structure corner position by interpolation, and can more accurately estimate the sound power, and the interpolation method is not relevant to the physical performances and boundary conditions of the structure.

Description

1. Technical Field [0001] The present invention proposes a method for estimating the low-frequency radiation sound power of a structure under the condition of under-sampling of the vibration distribution. By measuring the normal vibration velocity at a limited position on the structure surface, the vibration velocity at other positions of the structure is obtained by interpolation in a certain way, and the sound power is accurately predicted . 2. Background technology [0002] Prediction of structural vibration and sound radiation can be used in ship design, noise control, and civil production. The more the number of vibration sensors placed on the surface of the structure, the more accurate the estimation of acoustic radiation. For structures with general shapes, Helmholtz integration can be used to calculate the radiated sound field (Rayleigh et al, 1878); for structures with special regular shapes (such as flat, spherical, cylindrical, etc.), the vibration mode can be used to...

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Application Information

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IPC IPC(8): G01H17/00
Inventor 丛超楠陶建成邱小军
Owner NANJING UNIV
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