Method for measuring acoustics parameter of viscous-elastic material under medium-high frequency

Abstract

This invention relates to a interim / high frequency viscoelastic material acoustic parameter measurement method, and the major content of the method is using Legendre function to expand the scattering field acoustic dies function of the viscoelastic ball, and compare the Legendre expansion coefficients of the experiment and the Legendre coefficient expression derived from the theoretical formulas, establishing the simultaneous equations, and using optimization algorithms for solving the solution of equations, which is the acoustic parameters of measured material. The method avoids the sound pressure phase measurement, and only need to know the scattering field sound pressure amplitude. The method can simultaneously get material latitudinal / longitudinal wave parameters, no need separately measuring each parameter. It gives more accurately error correction model, to improve the accuracy of parameters measurement, particularly applicable to interim / high frequency viscoelastic material acoustic parameter measurement that difficult to achieve in conventional methods, and with a broad frequencies range.

Description

technical field [0001] The invention belongs to the field of underwater acoustic materials and relates to a method for measuring acoustic parameters of viscoelastic materials at medium and high frequencies Background technique [0002] At present, there are many methods for measuring the acoustic parameters of viscoelastic materials. From the theoretical basis of the measurement, they can be roughly classified into two categories. One is the vibration measurement method that calculates the mechanical parameters by measuring the vibration characteristics of the material sample. The other is an acoustic measurement method that obtains its mechanical parameters or acoustic parameters by measuring the acoustic properties of the material. [0003] The vibrating beam method is a classic method for measuring the complex elastic modulus of viscoelastic materials, and it is also the most common measurement technique. Its principle is to derive the elastic modulus and loss of the meas...

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Problems solved by technology

The key to this method is the measurement of the phase change caused by inserting the test board between the sound source and the receiver, but the phase change is very sensitive to the material properties of the board, and this sensitivity largely affects the accuracy of this testing technique. sex

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