System error calculation and analysis of underwater sound absorption coefficient measurement experiment

Abstract Measuring the sound absorption coefficient by the impedance tube method is an important step in the research and development of the underwater sound-absorbing materials and structures. Generally, the experimental results are more persuasive than the theoretical results are. However, the system errors caused during the preparation and installation process of the sample to be tested are often ignored, which will affect the reliability of the experimental results. In order to reduce the system errors, three factors that may cause the system errors, including the slit length and width, the inclination angle and the surface finish, are proposed in this paper. First, a finite element (FE) simulation experiment environment of the underwater sound absorption coefficient measurement by the impedance tube method is established and the correctness of the FE algorithm is verified. Then the effects of the related parameters on the sound absorption coefficient of rubber are studied. When the sound absorption coefficient is within a certain acceptable error range, the restrictions of the related parameters are given. The achieved conclusions have reference value for reducing the system errors and improving the reliability of the experimental results.