Testing device and testing method for sound absorption ability of material based on schlieren method

Abstract

The invention discloses a testing device and a testing method for sound absorption ability of a material based on a schlieren method. The testing device comprises a laser device, a sound wave generator, a light gathering lens, a light shielding plate with a slit, an incident light collimating mirror, an output light collimating mirror, a knife blade and a camera, wherein the slit is positioned atthe focus plane of the incident light collimating mirror; the knife blade is positioned between the output light collimating mirror and the camera; the edge of the knife blade is positioned at the focus plane of the output light collimating mirror. The testing device has the advantages that under the action of the sound wave generator, the refractive rate of air is changed, the light ray passing through the air disturbance area is deflected, the edge of the knife blade is used for blocking the deflected light ray, and then the deflected light ray is prevented from entering the camera; an imagecollected by the camera can present the dark and bright alternative strikes; the sound absorption ability of the to-be-tested material can be obtained by the ratio of gray value of dark and bright strikes on the image; the sound absorption ability of the to-be-tested material can be visually tested at high precision; the testing device is used for testing the sound absorption ability of the material.

Description

technical field [0001] The invention relates to the technical field of a material sound absorption capacity testing device. Background technique [0002] The current method for testing the sound absorption capacity of materials in the laboratory is mainly the reverberation method. The reverberation method refers to a room with an average sound absorption coefficient close to zero and a long reverberation time (meeting its corresponding indoor size, and the background noise is less than or equal to 35dB and other conditions) Arrange a loudspeaker in any corner of the room, and place three twelve-body microphones with different heights of measuring points away from the sound source, first measure the reverberation time of the sound of each frequency when no sound-absorbing material is placed in the room (that is, the time required for the sound to decay to 60dB), and then measure the reverberation time of different materials and different areas of the same material, through th...

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Problems solved by technology

[0003] The technical scheme of using the reverberation method to test the sound absorption capacity of materials has the following shortcomings. First, due to the influence of factors such as the shape of the reverberation chamber, the position of the sounding body, the size and distribution of the scattering body, the test accuracy is not high; secondly, the sound wave Particles cannot meet the requirements of randomness, which is easy to cause experimental errors, and cannot realize the visual observation of the acoustic wave attenuation gradient

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