STUDY ON THE SOUND ABSORPTION PERFORMANCE OF COPPER FILM-COPPER FIBER COMPOSITE STRUCTURE

To improve the acoustic absorption performance of metal fiber materials, a copper film-copper fiber composite structure material, called FFM, is designed. The copper film helps to transmit the vibration of incident sound waves to the copper fiber matrix, which dissipates the sound energy and achieves efficient absorption. First, the COMSOL simulation software is used to establish the acoustic absorption model of FFM. Through calculation, the influence of parameters such as the porosity of the copper fiber matrix, the diameter of the copper fiber, the thickness of the copper fiber matrix, and the thickness of the copper film on the acoustic absorption performance of FFM is analyzed. Then the test results were compared with the simulation results. The accuracy of the model was 95%, which verified the effectiveness of the sound absorption model. Finally, the model calculates the energy efficiency ratio of FFM under different parameters. When the energy efficiency ratio is the largest, the acoustic absorption performance of FFM is the best, The optimal parameters are as follows: the porosity of the copper fiber matrix is 75%, the diameter of the copper fiber is 0.04 mm, the thickness of the copper fiber matrix is 12 mm, and the thickness of the copper film is 0.05 mm. Under this parameter, the average absorption coefficient of FFM is 0.6, and the initial frequency is 416 Hz. The average absorption coefficient of 12 mm copper fiber is 0.36, and the initial frequency is 2128 Hz. It can be seen that the FFM structure has excellent acoustic absorption performance, and it can achieve efficient broadband acoustic absorption characteristics even when the sample thickness is relatively thin.