ZHAO Xinyang1, MEI Zhiyuan1, ZHU Yi1, DU Du2
JOURNAL OF VIBRATION AND SHOCK. 2023, 42(5): 205-214.
In order to accurately predict the target strength of non-watertight structure with acoustic coating on the surface and pressure cylinder inside, a new parameter inversion method is constructed in this paper. Combining genetic algorithm with nonlinear programming, a double-layer elastic media layer inversion model is established using the layered media theory to replace the acoustic coating layer containing complex internal structure,taking into account the oblique incidence, multiple scattering,anastomosis effect and transverse wave velocity threshold.The inversion model and the original structure have basically the same reflection coefficient and transmission coefficient at all angles. Furthermore, A complex non-watertight structure with an acoustic overlay laid on the surface and a pressure-resistant cylinder inside is constructed by COMSOL Multiphysics , and the shell is an equivalent structure composed of two inverted materials, and calculate its acoustic scattering characteristics. The results show that in the case of monostatic,the target strength values of the original structure and the equivalent structure are basically the same, and the overall error of the research frequency band when incident in each direction is less than 1.5dB; In the case of 30 ° bistatic, the peak and trough trends of the target strength of the original structure and the equivalent structure at each frequency are the same, and the overall error of the research frequency band when incident in each direction is less than 2dB. In the middle and high frequency band, the target intensity directivity of the original structure and the equivalent structure is better; In the middle and low frequency bands, the target intensity directivity of the original structure and the equivalent structure is basically the same, but there are differences in amplitude; Overall, in the range of -30 ° ~ 30 °, except for a few frequencies, the original structure is basically consistent with the target strength of the equivalent structure.