Acoustic coating layer insertion loss measurement method based on multi-channel space-time inverse filtering technology

Abstract

Provided is an acoustic coating layer insertion loss measurement method based on a multi-channel space-time inverse filtering technology. The method comprises the following steps that 1, a multi-channel space-time inverse filtering emission signal is generated; 2, a direct signal is collected on the condition that a test sample does not exist; 3, a transmission signal is collected on the condition that the test sample exists; 4, an insertion loss measured value is calculated. According to the acoustic coating layer insertion loss measurement method based on the multi-channel space-time inverse filtering technology, a channel impulse response function containing information of a circuit channel and an underwater acoustic channel is obtained through constant interval emission of an emission array transducer and sequential receiving of a hydrophone, and the purpose of receiving a space acoustic energy focus and a time domain impulse waveform focus of the hydrophone is achieved through the simple and effective multi-channel space-time inverse filtering technology, so that the purposes of multi-path signal separation and reverberation suppression in acoustic coating layer insertion loss measurement are achieved, the space resolution of measurement parameters is improved, and the method is particularly suitable for acoustic performance tests of low-mid frequency materials. Meanwhile, it is verified that the method is effective in acoustic coating layer insertion loss measurement.

Description

technical field [0001] The invention relates to a method for measuring the insertion loss of a large sample of an underwater acoustic cover. Underwater acoustic covering is a widely used and crucial underwater component in hydroacoustic engineering. In order to evaluate the insertion loss performance of acoustic covering samples, insertion loss measurement of large samples under laboratory conditions is the main method. Background technique [0002] Acoustic coating refers to special functional acoustic materials and structures laid on underwater components, and is an important means for underwater components to achieve acoustic stealth. With the rapid development of viscoelastic materials and the in-depth research of acoustic stealth technology, the acoustic cover products have been relatively complete. According to their different acoustic functions, they can be divided into sound-absorbing tiles, sound-insulating tiles, vibration-suppressing tiles, decoupling tiles, array...

AI Technical Summary

Problems solved by technology

The measurement of large samples in the free field has limited ability to measure low-frequency acoustic performance parameters. As the frequency decreases, since the sound-absorbing materials around the measurement environment cannot completely absorb sound waves, the reflection of low-frequency sound waves at the boundary cannot be ignored, and the measurement signal is affected by reverberation. severe interference

At the same time, since the width of the main lobe of the beam will gradually increase with the decrease of the frequency, that is, the resolution of the main lobe will gradually decrease, and the size of the sample to be tested is limited. When the width of the main lobe is larger than the size of the sample to be tested, it will affect the test results. large error

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