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Device for measuring sound absorption coefficient of acoustic material by use of pulse method and measuring method

A technology of sound absorption coefficient and acoustic material, which is applied in the analysis of solids using sonic/ultrasonic/infrasonic waves, which can solve the problems of cumbersome testing work and increase testing time, and achieve the effect of avoiding secondary errors and overcoming phase matching.

Active Publication Date: 2014-09-10
NORTHWESTERN POLYTECHNICAL UNIV
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  • Claims
  • Application Information

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Problems solved by technology

The transfer function can be measured by exchanging two microphones to eliminate the mismatch between the two microphones, and the single-microphone method can also be used for sequential measurement, so there will be no problem of phase and amplitude mismatch, but it will increase the test time and make the test work easier. cumbersome

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  • Device for measuring sound absorption coefficient of acoustic material by use of pulse method and measuring method
  • Device for measuring sound absorption coefficient of acoustic material by use of pulse method and measuring method
  • Device for measuring sound absorption coefficient of acoustic material by use of pulse method and measuring method

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Embodiment Construction

[0024] Describe the present invention below in conjunction with specific embodiment:

[0025] In this example, a measurement experiment of sound absorption coefficient was carried out on a fiber material with a thickness of 25 mm.

[0026] The measuring device used in this embodiment includes a sound tube, a pulse sound source, a microphone, a power amplifier, a signal conditioner, an adapter, and a data acquisition device.

[0027] The sound tube is composed of a large-diameter cylindrical tube, a conical tube and a small-diameter cylindrical tube which are coaxially and fixedly connected in turn. Tube length is 1360mm. The inner diameter of the large-diameter cylindrical tube is the same as the diameter of the pulse sound source. The pulse sound source is installed in the large-diameter cylindrical tube. The inner and outer diameters of the small-diameter cylindrical tube are 27mm and 34mm, respectively, and are capable of propagating broadband plane pulse waves (frequency...

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Abstract

The invention provides a device for measuring the sound absorption coefficient of an acoustic material by use of a pulse method and a measuring method. The device comprises a sound tube, a pulse sound source, a microphone, a power amplifier, a signal conditioner, an adapter and a data acquisition device, wherein the sound tube is formed by coaxially and fixedly connecting a large-diameter cylindrical tube, a conical tube and a small-diameter cylindrical tube in sequence; two through holes vertical to the central axis of the small-diameter cylindrical tube and used for mounting the microphone are formed on the side wall of the small-diameter cylindrical tube; the pulse sound source is mounted in the large-diameter cylindrical tube; and the outer end of the small-diameter cylindrical tube is in threaded connection with a rear cover. The measuring method comprises the following steps of: obtaining a frequency response function of the whole measuring system; obtaining an excitation signal spectrum of the required pulse sound source; and exciting the pulse sound source by use of the excitation signal of the required pulse sound source and measuring to obtain the sound absorption coefficient of a to-be-measured sample. The device and method provided by the invention avoid secondary error caused by decomposing a sound field in a frequency domain in the traditional method, and also overcome the problem of phase matching in the traditional multi-microphone method.

Description

technical field [0001] The invention relates to the technical field of acoustic material testing, in particular to a measuring method for measuring the sound absorption coefficient of acoustic materials by using a pulse method. Background technique [0002] In the field of acoustic tube acoustic testing, the current measurement technology for the sound absorption coefficient of acoustic materials is based on the transfer function method to measure in the impedance tube. For example, the corresponding value is obtained by measuring the transfer function at different positions in the acoustic tube. The main problem is the phase matching between the multiple microphones. Two microphones can be used to exchange the measurement transfer function to eliminate the mismatch between the two microphones, and the single-microphone method can be used for sequential measurement, so there is no problem of phase and amplitude mismatch, but it will increase the test time and make the test w...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N29/12
Inventor 侯宏孙亮杨建华
Owner NORTHWESTERN POLYTECHNICAL UNIV
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