Vibration reconstruction for a point-excited plate based on acoustic radiation modes and sound pressure measurement

Abstract

The inverse problem of sound radiation from a vibrating structure is one of the key problems in vibro-acoustics; however, sound source reconstruction with sound pressure measurement still has challenges from sound field assumptions and measurement noise. Due to orthogonality and unrestricted source, Acoustic Radiation Modes (ARMs) are seen as promising basis vectors to realize sound source reconstruction. Here, near-field ARMs obtained by the pressure-velocity method were proposed to construct a series of orthogonal basis vectors for the vibration velocity of a point-excited rectangular plate, and a new procedure of rearrangement and truncation of basis vectors is proposed to obtain the top-ranking vectors with their contribution. Finally, vibration reconstruction is realized with least finite vectors to reach a certain accuracy. Numerical simulations show that vibration reconstruction errors are below 10% with less than 20 orders of basis vectors at frequency range kL ≤ 2π and white noise SNR = 30 dB. The smaller distance of the measuring surface and lower frequency of sound lead to higher reconstruction accuracy and less necessary basis vectors. The factors affecting reconstruction accuracy were also studied by white noise level, amount of basis vectors, and number of measuring points.