Mixed Wave Superposition NAH Based On Missing Array For Mechanical Noise Source Location And Identification

As a part of the National Natural Science Foundation of China, this paper mainlystudies NAH-based microphone array technology gets the low-frequency informationof mechanical equipment’s key sound source. Near-field acoustic holography (NAH)is an effective technology for identifying noise source and visualizing acoustic field,its application makes the noise control of mechanical and electrical products, lownoise design and the design of sound quality easy. According to the needs of largeequipment’s acoustic fault detection and diagnosis, starting from the actualengineering applications, this paper studies the near-field acoustic holography basedon a small array of measurements. The main work of this article include:1) Firstly, this section clarifies the source of this article, reviews the researchstatus of NAH and array measurement technology. According to practicalapplication’s limitations and development trends of existing technology, the contentsof this article is identified.2) For the object of study, analysis of the principle of mechanical noise. Fornear-field acoustic holography based on the transformation of sound field, this paperdiscuss the impact parameters that affect the reconstruction accuracy. Wavesuperposition method resolves holographic aperture restrictions on traditional NAHtechnology.3) The simulation result shows the combination of Tikhonov regularizationmethod and statistically optimal near-field acoustic holography has higherreconstruction accuracy than the NAH based on Fourier transform.This paperproposes a hybrid wave superposition method NAH, in a small measuring aperture,the sound field information can be accurately reconstructed. Considering thecomplexity of the working environment of machinery and both sides of holographicare present sound source, propose hybrid wave superposition method for sound fieldseparation technique, that combines the best advantages of wave superposition and statistical optimal methods. This approach reduces the cost of the measurement andmake the experiment efficiency.4) An important aspect of near-field acoustic holography is data collection usinga microphone array measurements. This paper discusses how the missing array torebuild sound field, increase the microphone array points to improve the accuracy ofreconstruction; discuss combine plane array and some microphones to rebuild soundfield, increase the microphone array points to improve the accuracy of reconstruction;Simulation results shows the separation of the sound field is feasible under theabsence of array measurements.5) Finally, an experiment based on an array of missing data is conducted, it usesthe mixed wave superposition of near-field acoustic holography to rebuilt the soundfield of mechanical noise sources, it reconstructs the noise information, experimentachieves good result.