Research On Parameters Measurement Of High Sound Pressure Source Based On Resonace Coupled Tube Method

With the development of aerospace technology and defense industry,the demand for high-strength sound field measurement is increasing.The calibration of high-sound-pressure microphones is one of the important issues.At present,the resonant high sound pressure source with a sound pressure level higher than 140 dB can only perform dynamic range upper limit calibration and total harmonic distortion analysis on the microphone at a frequency of 500 Hz,and the high sound pressure calibration system based on the resonance coupled tube method is monopolized by the foreign company.In order to further study the mechanism of high sound pressure generated by the resonance coupled tube method,expand the design of high sound sources at multiple frequency points,and develop an automatic calibration system for high sound pressure microphones,this paper has carried out the following work:1.For the inapplicability of the modal analysis method and transfer matrix method of the resonance coupled tube at high resonance frequencies,an acoustic finite element simulation model based on ANSYS is proposed.The influences of the wall thickness,wall material and size of the resonance tube on the amplitude-frequency response of the sound pressure waveform at the end of the coupling tube are analyzed.Modeling and analyzing the harmonic suppression effect of the distortion suppression component,and analyzing the effect of the length and inner diameter of the component on the amplitude-frequency response at the end of the resonance coupled tube.Based on these,resonance coupled tubes with resonant frequencies of 500 Hz and 1000 Hz were designed.2.Based on the optimized design of the resonance coupled tube,the parameters of the high-sound pressure source of the resonance coupled tube were measured,and an automatic calibration system for high-sound pressure microphones was established based on the Lab VIEW platform.The system can achieve microphone linearity calibration and total harmonic distortion analysis at a sound pressure level of 114 dB～174dB.3.In order to further verify the accuracy of the measurement data of the high sound pressure source by the resonance coupled tube method,a high sound pressure source based on a pistonphone was developed,and the sound pressure source was generated at 20 Hz～500 Hz and 124 dB～174 dB.The high sound pressure source based on the piston sounder can be used as a verification and supplement for the high sound pressure source of the resonance coupled tube method to perform high sound pressure calibration on the low frequency band of the microphone.