A New Sound Absorption Material Based On Bionic Wood Structure By 3D Printing Technology

This paper simulates the natural structure of the inner conduits and pits of wood,and designs and uses 3D printing technology to prepare the sound-absorbing structure of bionic wood.The impedance tube transfer function method was used to investigate the influence of structural characteristics such as filling degree,perforation rate,aperture,side hole depth,upper and lower aperture ratio,and perforation tilt angle on the sound absorption performance of 3D printed bionic wood sound absorption structure,and the perforation rate was established.The mathematical model of the influence of the ratio of the upper and lower apertures and the inclination angle of the perforation on the sound absorption performance of the 3D printed bionic wood sound absorption structure provides a research basis for the design of the sound absorption structure of the customized frequency.The study mainly obtained the following conclusions:(1)The bionic wood sound absorption structure prepared by 3D printing technology has the same sound absorption performance as the wood perforated plate in the middle and low frequency range.The influence of perforation rate and aperture on the 3D printing sound absorption structure is also related to the wood perforation.The boards are basically the same.(2)In the mid-high frequency range,the 3D printed bionic wood sound absorbing structure has good sound absorption performance not possessed by the wood perforated plate.The 3D printed bionic wood sound absorbing structure with a perforation angle of 30° has a peak sound absorption coefficient of 0.93 at 5992 Hz.(3)The ratio of upper and lower perforations has a great influence on the sound absorption performance of the 3D printed bionic wood sound absorbing structure.In the mid-low frequency range of 50-600 Hz,the ratio of the upper and lower perforations of the main hole of the 3D printed bionic wood sound absorption structure increases,the resonance frequency moves toward the low frequency direction,and the peak of the sound absorption coefficient increases.In the mid-high frequency range of about 3500 Hz,the resonance frequency is basically the same as the ratio of the upper and lower perforations of the main hole increases,and the peak of the sound absorption coefficient decreases.(4)The perforation angle has a significant influence on the sound absorption performance of the 3D printed bionic wood sound absorbing structure.In the mid-low frequency range of 50-600 Hz,as the tilt angle increases,the resonance frequency of the 3D printed bionic wood sound absorption structure moves toward the low frequency direction,and the peak of the sound absorption coefficient rises;in the middle and high frequency range of about 3500 Hz,There is a resonant frequency but its sound absorption performance is poor;in the mid-high frequency range of 4000 Hz-6400 Hz,as the tilt angle of the perforation increases,the resonant frequency of the 3D printed bionic wood sound absorbing structure moves toward the low frequency direction.(5)According to the influence of different structural features of 3D printing bionic wood sound absorption structure on sound absorption performance,the mathematical model of upper and lower aperture ratio and resonance frequency is established respectively: y=-167x+501(frequency range: 50-600 Hz);perforation Mathematical model of tilt angle and resonant frequency: y =-167 x + 501(frequency range: 50-600 Hz),y =-0.79x2 + 16.8x + 6168(frequency range: 4000-6400 Hz).