Analysis of Low-Frequency Sound Insulation Characteristics of Simply Supported Locally Resonant Plate

Thin plate is a typical key structure of various transportation vehicles such as airplanes and high-speed trains. The sound insulation performance of the plate, especially the low-frequency sound insulation performance, has attracted extensive attention. In this paper, first, taking the finite rectangular locally resonant plate as the research object, based on the plane wave expansion (PWE) method, the theoretical model of sound insulation under simply supported four-sided boundary conditions is established. Secondly, the correctness of the model is verified by calculating the normal incident sound insulation. Thirdly, the influence of the target frequency of oscillator, the number of local oscillators, the additional mass ratio, and the spring damping on the sound insulation performance of the locally resonant plate is analyzed. Finally, a single-value index of low-frequency weighted sound insulation is introduced to perform a single-value evaluation of the sound insulation in the 20–250 Hz frequency band. Relative studies provide a reference for the sound insulation design of the locally resonant plate.