针对汽车驾驶室吸声材料的吸声系数的一种简便计算方法进行研究.根据吸声材料声阻抗率布置,得到吸声材料流阻率和孔隙率的计算公式,利用Matlab循环程序计算出流阻率和孔隙率,根据求得的吸声材料的流阻率和孔隙率,可以理论计算出汽车驾驶室吸声材料的吸声系数,为理论计算汽车驾驶室吸声材料的吸声系数提供一种简便方法.同时系统研究材料的吸声系数与吸声材料自身的流阻率、孔隙率和厚度以及入射声波频率的关系,在低频时吸声系数与材料的孔隙率和厚度成正比;当入射声波在0~500Hz范围内,驾驶室吸声材料的系数随流阻率的减小略有下降,但下降幅度并不显著;随着入射声波频率的提高,驾驶室吸声材料的吸声系数一般呈上升趋势.
A simple method to calculate sound absorption coefficient of the sound absorbing materials of the automobile cab is proposed.Based on the acoustic impedance arrangement of the sound absorbing materials,the formula for resistivity and porosity flow of the sound absorbing materials is obtained; then Matlab cycle is used to calculate flow resistivity and porosity,and based on the obtained figures,sound absorption coefficient of the sound absorbing materials in the automobile cab can be calculated theoretically; thus providing a simple method for the calculation of sound absorption coefficient of the sound absorbing materials in the automobile cab in theory.At the same time,the relationship of the sound absorption coefficient of the material,the resistivity,porosity and thickness and incident wave frequency of the sound-absorbing material is studied.Under the low frequency,the sound absorption coefficient and porosity and thickness is proportional.When the incident sound wave is in the range of 0-500 Hz,the coefficient of the cab sound absorption material decreases slightly with resistivity but the rate of decline is not significant; with the increasing frequency of incident sound wave,the sound absorption coefficient of the cab sound-absorbing material generally has an upward trend.