Study On Sound Absorption And Structural Style To The Noise Reduction Of Noise Barrier

A new noise barrier was invented in Xiaogan-Xiangfan freeway building engineering. The name of this new noise barrier is waste tire noise barrier. The sound absorption of it is batter than the common barriers, especially in the middle and low frequency band. How much the sound absorption of the sound absorbing material in every frequency contribute the total sound attenuation is the mean content of this article.The formula of absorption noise reduction is derived from the basic acoustic theory in this paper. The formula is related to the absorption coefficient in various frequencies of sound-absorbing material and the energy distribution in various frequencies of the noise sources. The formula of absorption noise reduction is 0.1 and the absorption impact of the diffraction is further studied. We can apply the results to sound absorption of sound barriers in highway. The research indicates that the effect of absorption noise reduction lie on the absorptive capability but not the average sound absorption coefficient. Which should be attention to is that absorption noise reduction is composed of various frequency and the dimension is dB(A) used the A weighting network .When the high frequency sound wave barge up against the sound barrier, it is easy to be ward back; but the low frequency is easy to diffract and for people it is not sensitive if the low frequency is decreased much. So the results penman deduced are larger than actual value and we should correct the low frequency. This problem will discussed in the text.Apart from sound absorption function, the paper has also taken different structures of acoustic spectrum into consideration and applied them into acoustic material production to yield better noise reduction effect. The research shows, changes only in acoustic spectrum structure will not prominently lead to noise reduction efficiency of spectrum, absorptive materials structure added will greatly improve the efficiency. To reach the uniformity of technology, economy and environment of acoustic spectrum construction, the paper has presented economical performance analysis of the project.The research group has developed a set of noise prediction software during the project construction of acoustic spectrum that is road traffic noise model program. Another job of the research subject is that we use absorption noise reduction formula to improve deficiency of the function about absorption noise reduction .As a result, the result of the software is more accurate and the software is more convenient for customers.