Preparation And Sound Absorption Performance Of Perforated Fiberboard With Bionic Wood Porous Structure

In this study,the perforated fiberboard with side hole structure was prepared by designing perforated structure and punching method,and the sound absorption performance of perforated fiberboard was tested by impedance tube transfer function method.The effects of main hole diameter,perforation rate and inclination angle on sound absorption performance of perforated fiberboard were studied by using orthogonal experiment,and the optimal process parameter was obtained.The influence of side hole number,side hole thickness,side hole depth and perforation inclination angle on sound absorption performance were studied by controlling variable method.In order to take advantages of all superior perforated structure,the bionic perforated fiberboard with combined hole sound absorption structure was designed.And on the basis of all experimental data,the mathematical model was established to show the relationship between side hole structural parameters and sound absorption frequency.The main conclusions were summarized as follows:(1)The primary and secondary order of factors affecting the peak sound absorption coefficient of perforated fiberboard was inclined angle>diameter of the main hole>perforation rate;the optimal process parameters for preparing perforated fiberboard were main hole diameter 3 mm,perforation rate3.14%,and inclined angle 30°.(2)The number,thickness and depth of the side hole all had great influence on the sound absorption performance of bionic perforated fiberboard.The bionic perforated fiberboard showed excellent sound absorption performance in low and mid-range frequency bands,and the peak sound absorption coefficient was higher than 0.94;When the side hole number was 2,the thickness was 3 mm,and the depth was 4 mm,the resonance frequency of the bionic perforated fiberboard was 3632 Hz,and the peak sound absorption coefficient could reach 0.67.(3)The inclination angle of the perforation also has significant effect on the sound absorption performance of the bionic perforated fiberboard.In low frequency,the maximum difference value of the sound absorption peak at different inclination angles was 0.27,and the resonance frequency changed to212 Hz;In high frequency,the difference was 0.43,and the resonance frequency span was 2162 Hz;With the increase of inclination angle,the peak value of the sound absorption coefficient increased first and then decreased.The bionic perforated fiberboard had the best sound absorption performance when the inclination angle was 30°.(4)The sound absorption performance of the bionic perforated fiberboard with the combined-hole sound-absorbing structure was effected by the used hole structures,the peak sound absorption coefficient and the resonance frequency value were mostly in the range of this two structures;the sound absorption coefficient of the combined hole bionic perforated fiberboard was above 0.20 when the frequency was higher than 3000 Hz,and the frequency band width also increased significantly.(5)With the help of mathematical function equations,the influence of side hole structure parameters on the sound absorption performance of the bionic perforated fiberboard was studied.The relationship between side hole number and sound absorption frequency were as follows:y=-467x+4555(mid-to-high frequency band);The relationship between side hole thickness and sound absorption frequency were as follows:y=0.629x~2+6.777x+276(mid and low frequency band),y=-178.1x+4579(mid and high frequency band);The relationship between side hole depth and sound absorption frequency were as follows:y=-5.285x~2+28.14x+275.8(low and middle frequency band),y=-87.42x~2+134.5x+4520(mid and high frequency band);The relationship between perforation tilt angle and sound absorption frequency were as follows:y=-0.033x~2-1.592x+400.3(mid and low frequency band),y=0.429x~2-58.87x+5107(mid and high frequency band).