| At present,noise pollution seriously affects living comfort,and the acoustic performance of wall structure of light timber construction is the key to ensure building comfort and measure dwelling environment quality.However,there exist a series of problems such as poor acoustic performance in the midd le and low frequency acoustic wave.Based on the Helmholtz resonance structure in the low frequency sound waves within the sc ope of efficient and sound absorption performance,combined with en vironmental noise and wall structural characteristics of light timber buildings,the structural design and analysis of the interior wall of light timber construction are carried out.This paper explores a kind of effective solution to light timber building wall within the scope of the low frequency sound wave in the acoustic problems.This study takes the light timber building wall structure as the research object.Based on the Helmholtz resonance str ucture principle,the structural optimization design and acoustic performance of the wall structu re are studied.First,the field investigation is carried out to an alyze the influence of noise sources on the building environment noise.Second,the Helmholtz resonance structure with high efficiency sound absorpti on performance in the medium and low frequency was applied to the light timber wall structure.The structur e design of the wall unit,impedance tube test and COMSOL MULTIPHYSICS software simulation w ere carried out to obtain the change rule of the sound ab sorption performance of the aperture embedded wall unit structur e.Third,the sound-absorbing performance o f different-specification specimens were studied by impedance tube test,which can explore factors of affecting sound absorption performance of apert ure embedded wall unit structure.And the aperture embedded wall unit structure is applied to the actual wall structure to design the light timber building wall structure.Finally,according to the conclusion of preliminary experimental research and the preliminary design of wall structure,the structure design and pro duction of the wall composite structure are carried out.Then,the sound-absorbing performance of wall composite structure is tested by reverberation chamber test.The main research conclusio ns show that:(1)In the test frequency section,the influence of traffic noise on the middle and high frequency is obvious,while the influence of equipment noise on the middle and low.The influence of traffic noise on the indoor environmental noise can be basically ignored in the frequency range of 0-500 Hz and 5000-7000 Hz.It mainly affects the indoor enviro nmental noise in the middle and high frequency bands,especially the frequency range of 1000-3000 Hz.The influence of equipment noise on the indoo r environmental noise can be basically ignored in the frequency range of 0-150 Hz and 5000-10000 Hz.It mainly affects the indoor environmental noise in the middle and low frequency bands,especially arou nd the frequency range of 200 Hz and 1000-2000 Hz.(2)In the test frequency segment(90-1600 Hz),the overall acoustic performance of aperture embedded Helmholtz stru cture of the wall unit is significantly improved.Compared with the ordinary structure,the sound insulation performance of the aperture embedded Helmholtz structure does not change significantly in numerical valu es,but the overall stability is enhanced.The sound absorption performance of the aperture embedded Helmholtz structure is obviously better than that of the ordinary structure,especi ally in the low frequency acoustic wave range.(3)In the test frequency section(90-1600 Hz),the simulation results of aperture embedded Helmholtz structure of the wall unit are basically consistent with the test results.However,there are certain errors.The numerical errors of the sound absorption coefficient at frequency points of 100 Hz,200 Hz and 630 Hz are relatively large,and the curves of the sound absorption coefficient in the simulation and test are different in the frequency range of 90-250 Hz.(4)To a certain extent,by adjusting the embedded hole size,it can adju st the acoustic performance of the wall uni t structure,such as sound absorption peak,resonance frequency and sound absorption bandwidth of the wall uni t structure.When the length of the embedded hole is kept unchanged,the whole curve moves to the low frequency with the decrease of the aperture.The resonance frequency corresponding to the sound absorption peak decreases,and the peak value of the first order sound absorption in creases.With the aperture of the embedded hole unchanged,the whole curve mo ves towards low frequency as the hole lengt h increases.The resonance frequency corresponding to the sound absorption peak decreases,and the peak value of the first order sound absorption increases.(5)The aperture embedded Helmholtz structure wall composite structure has good sound absorption performance in the low frequency range,especially at the frequency of 100 Hz,which basically achieves perfect sound absor ption.However,in the middle and high frequency range,the structure basically does not abso rb sound.Compared with the ordinary structure,the sound absorption performance of the aperture embedded Helmholtz structure is enhanced to a certain extent withi n the test frequency range.And in the low frequency range,the sound absorption bandwidth is widened to some extent as the sound absorption coefficient is increased.The average sound absorption coefficient and NRC are also improved.However,as far as the structure itself is concerned,the sound absorption band is still narrow.It has good sound absorption performance for specific freque ncies,but the overall sound absorption performance does not meet the requirements,which needs further optimization and improvement.In conclusion,this study optimizes and improves the wall structure by applying Helmholtz resonant structure with aperture embedded to the light-timber construction.Through experimental test and simulation analysis,it is found that the combination of Helmholtz resonant structure with aperture embedded and light timber wall structure can improve the sound absorption performa nce of the wall in low frequency incident sound band without affecting the sound insulation performance of the wall.The study is helpful to improve the acoustic environment of the timber structure and improve living environment comfort.It is expected to provide basic support for the sound absorption and noise reduction technology of light timber building wall structure,w hich has high popularization value and practical significance for promoting the optimization design and engineering application of acoustic performance of light timber building wall structure and promoting the sustainable and healthy development of modern wood structure market in China. |
