Influence of Multiple Factors on Underwater Semi-Active Sound Absorption of 2-1-3 Piezoelectric Composite and Root Cause Analysis

2-1-3 piezoelectric composite is advantageous for its high piezoelectricity, mechanical stability and ease of preparation. Applying piezoelectric shunt damping technology in underwater semi-active sound absorption increases the adjustability of sound absorption performance. This paper analyzes the underwater semi-active sound absorption performance of 2-1-3 composite. The theoretical model and finite element model of 2-1-3 composite are established and the sound absorption coefficient of the composite coating is deduced based on transfer matrix and Mason equivalent circuit theory. The effects of the volume fraction of PZT-5H phase μ, the aspect ratio α and the shunt circuit on the sound absorption coefficient are studied and the root causes are analyzed. The results show that μ and α can affect the peak frequency, bandwidth and the range between open-circuit and short-circuit peak frequencies by changing the longitudinal wave velocity, mechanical loss factor and electromechanical conversion coefficient of the composite. Shunt circuits can adjust peak frequency and bandwidth by changing the elastic constant component c33 and mechanical loss factor of the composite. The conclusions of this study have value as reference for the design of underwater semi-active sound-absorbing material in various application scenarios.