Active Muffler Study Based On Piezoelectric Materials

Active muffler is used to finish the work by active sound absorption principle.The main content of this paper is to design the structure of the active muffler, analyze its theoretical basis and working principle, and design the control system of the active sound absorption structure. Because the active muffler of low, middle and high frequency noise has a good inhibitory effect, especially on the low frequency noise, so active muffler in military, automobile, ship and other areas has broad application prospect, the research has practical significance.Firstly, this paper describes the active muffler design concept:with two layers of PVDF film as a pressure sensor; piezoelectric materials as active sound absorption materials, the piezoelectric material piezoelectric ceramics (PZT-5); with the porous sound-absorbing material as a passive absorption material, the three kinds of organic materials combined to work together to achieve the purpose of active sound absorption. Subsequently, according to the spring ball vibration device proposed the idea of active sound absorption, and through the MATLAB software on the programming and simulation, in order to verify the idea can be realized; delay method based on digital sound field, with two pressure sensors were used to detect the incident sound pressure and anti radiation pressure, and separates the two sound pressure; theoretical calculation should be loading pressure of the piezoelectric ceramic voltage using MATLAB software programming, simulation of the calculation process, get loaded piezoelectric ceramic electric voltage change along with the changes in the thickness of the ceramic electric pressure under different incident sound frequency.Two control methods are proposed in this paper, which are indirect method and direct method for the design of the control system of active muffler. The two methods are programmed by MATLAB software, and the results are analyzed and compared in order to select a more suitable control method.On the basis of theoretical analysis, the experimental platform of active muffler is built. The data before and after noise control are compared and analyzed in detail. It is concluded that the active noise control has good control effect on low, medium and high frequency noise.