Analysis On The Thickness Polarization Theory Of Thin Circular Piece Transducer And Experimental Study Of Acoustic Reflection Coefficient

With the rapid development of technology, research on the physical properties of underwater acoustic materials has attracted much attention. Among them, the reflection coefficient is an important parameter of the physical properties of underwater acoustic materials. This is due to the reflection coefficient plays a "link" role in the petroleum exploration. It can convert the curves obtained from well logging into seismic data and can also change seismic data into simulate well logging. In the deeper area of petroleum exploration, the reflection coefficient can be calculated and the energy of the reflected wave can be estimated by using the measured downhole data. Thus how to get acoustic reflection coefficient of the underwater acoustic materials precisely and which factors will influence the reflection coefficient become important subjects in the study of acoustics.Firstly we did a theoretical analysis on a thin circular piece transducer acoustic thickness direction of polarization and calculated the mathematical equation of the electro acoustic conversion on the transmit side and the mathematical equation of the acoustic electric conversion at the receiving end about the equivalent circuit. Choosing different excitation signals to construct the relationship between the signal excitation, the electro acoustic conversion and the radiated acoustic signal on the transmit side. At the same time, we analyzed the relationship between the acoustic electric conversion and the measured acoustic signals at the receiving end. By analyzing the variation of acoustic signals at three different excitation signals, finally we selected the better gated sinusoidal excitation signal as the drive of a thin circular piece transducer. Because the experimental environment and experimental test system affect the test results, firstly we calculated the sound wave propagation velocity of the transducer in the actual measurement, which provides a real data parameter for the theoretical simulation of the reflection coefficient. Secondly, the establishment of a sound wave to the liquid-solid interface model to calculate the relationship between the reflection coefficient and the incident angle when the material aluminum and plexiglass is used as the solid interface.Then we used the free field testing method in the actual measurement. Its advantage is that the measuring environment is similar to the practical application environment and the acoustic signal emitted by the thin circular piece transducer can be incident to the material at any angle. The amplitude variation of acoustic signals at different angles of incidence is measured. By analyzing the theory and the actual measurement graph, it is known that the size of the reflection coefficient is related to the incident angle.This paper studied the relationship between the reflection coefficient and the incident angle of sound waves in the liquid-solid interface, which for the establishment of new acoustic logging model and the design of new model of acoustic well logging instrument provides a theoretical basis.