The parametric source measuring method for characteristics of underwater acoustic materials in a pressure vessel

A kind of truncated wideband parameter array with a primary frequency of 500 kHz and a difference frequency range of 1 kHz to 30 kHz was designed as a sound source of acoustic materials measurement system.By analyzing the theoretical calculation and actual measurement results of the array directivity of the truncated wideband parameter source in typical frequencies,it was showed that their result curves were basically consistent,and the model was correct.The application of bell-type short-duration pulse could carry out wideband measurements for characteristics of underwater acoustic materials,and reduce the effects of diffraction from the panel edges.The measurement system was established in Hangzhou Applied Acoustic Research Institute for measuring the sound pressure reflection coefficient,pressure transmission coefficient and absorption coefficient of the large area panel sample of underwater acoustic material in the pressure vessel.The size of tank is Φ 4 m×12 m,the maximum hydrostatic pressure is 4.5 MPa,and the measuring frequency range is 1-30 kHz.The measurements for standard sample (the size of 1 m×1 m) showed that the measured curves had a good agreement with theoretical curves,the measurement method was verified.Then,the sound absorption property of the rubber plate sample was measured and effective assessed under different hydrostatic pressures.The potential application value of parameter source using in the limited water area such as pressured vessel is confirmed further.