The Technology Research On Measuring Underwater Acoustic Materials Low-frequency Sound Insulation Performance Based On Double Reverberation Box

The development direction of the sound insulation performance of materials often depends on the needs of underwater vehicles,and gradually develops towards better low-frequency performance and stronger pressure resistance.The incident direction of sound waves is an important aspect to be considered in the measurement of underwater sound insulation performance of materials.In practical applications,sound waves often propagate to the surface of the material in random incidence,which makes the existing conventional calculation formulas not suitable for the calculation of sound insulation under this condition.In this paper,a device for measuring the sound insulation performance of random incident materials in an underwater low-frequency pressurized environment based on a double reverberation box is established,and the corresponding theoretical simulation and experimental measurement research work is carried out.The measurement device in this article consists of three main parts: a rectangular parallelepiped reverberation box as the sound source chamber,a cylindrical shell and spherical shell combined structure as the sample chamber,and a reverberation box of the same size as the receiving chamber.Each part is connected in sequence to form a whole.Applying a force source excitation in the sound source room to simulate random incidence of sound waves,and pressurizing in the sample room to simulate a pressurized environment,and collecting data in the receiving room to achieve the final measurement purpose.The finite element simulation software is used to simulate the measuring device as a whole,and the sound insulation of the material under different pressures is simulated and calculated by direct and indirect methods.Three different rubber materials are used in the numerical simulation,and carrying out a simulation study on the change of sound insulation under four different pressure conditions.A simulation study of the change law of sound insulation with material thickness and perforation rate was carried out for one of the rubber materials,and on this basis,the numerical simulation study of the change law of sound insulation with pressure was further carried out.On the basis of simulation research,a double-reverberation test measurement device and test samples of the same proportion as the simulation were fabricated and experimental measurement research was conducted,and the conclusions are similar to the simulation results.Through the numerical simulation and experimental measurement research in this article,it is proved that the used measuring device can measure the sound insulation performance of the material under the condition of low frequency pressure random incidence,which will play an important reference role for future work.