Acoustic Performance of Natural Fiber Felts for the Automotive Industry

Abstract

Passenger comfort is an important parameter in the design process of the car. Noise caused by many factors in the vehicle significantly affects passenger comfort. Insulators are used to reduce noise and these insulators are usually made of fibrous or porous petrochemical-based materials. Recently, natural materials have begun to replace petrochemical-based materials due to environmental and health problems. Natural fiber materials offer alternatives such as felts made from recycled cotton, hemp, and kapok fibers. These materials have various acoustic performance properties depending on their density, thickness, and structural differences. There are some tests performed to evaluate the performance of materials for specific uses. To evaluate the acoustic performance of the felt, parameters such as sound absorption coefficient and sound transmission loss are considered. In the tests performed using an impedance tube and a reverberation chamber, it was investigated how the properties of the material affected these parameters. The results were that at higher thickness and density, sound absorption generally increased, while sound transmission loss decreased. The findings of the study are an important example for the selection and optimization of acoustic insulation materials and will contribute to the development of more effective insulation solutions in the automotive industry.

Keywords

• Fiber Felt
• Sound Transmission Loss
• Sound Absorption Coefficient
• Reverberation Cabin
• Impedance Tube
• Recycled Cotton
• Kapok Fibers
• Hemp Fibers

References

1. [1] Karabulut A, Şahman H, Korkmaz BŞ. Investigation of Vehi-cle Engine Driving Comfort Used in Vibration Dampers. IJASTECH. 2022;6(3):302-8. doi:10.30939/ijastech.1098514
2. [2] Crocker MJ, editor. Handbook of noise and vibration control. Cambridge (MA): John Wiley & Sons; 2007. ISBN: 978-0-471-39599-7
3. [3] Meriç C, Erol H, Özkan A. On the sound absorption perfor-mance of a felt sound absorber. Appl Acoust. 2016;114:275–80. doi: 10.1016/j.apacoust.2016.08.003
4. [4] Karagöz M, Tuncay B. An Engine Mount Design and Vibra-tion Analysis. IJASTECH. 2020;4(3):164-70.
5. [5] Narang PP. Material parameter selection in polyester fibre insulation for sound transmission and absorption. Appl Acoust. 1995;45(4):335–58. doi:10.1016/0003-682X(95)00007-V
6. [6] Nick A, Becker U, Thoma W. Improved acoustic behavior of interior parts of renewable resources in the automotive indus-try. J Polym Environ. 2002;10(3). doi:10.1023/A:1021124214818
7. [7] Zhang D, Zhou X, Gao Y, Lyu L. Structural characteristics and sound absorption properties of waste hemp fiber. Coat-ings. 2022;12(12):1907. doi:10.3390/coatings12121907
8. [8] Çakmakkaya M, Kunt M, Terzi O. Investigation of polymer matrix composites in automotive consoles. Ijastech. 2019;3(3):51–6. doi:10.30939/ijastech.513332

9. [9] Fung W, Hardcastle M. Textiles in automotive engineering. Cambridge: Woodhead Publishing Limited; 2001. p. 212–5. ISBN: 9781855738973.
10. [10] Bujoreanu C, Nedeff F, Benchea M, Agop M. Experimental and theoretical considerations on sound absorption perfor-mance of waste materials including the effect of backing plates. Appl Acoust. 2017;119:88–93. doi: 10.1016/j.apacoust.2016.12.010
11. [11] Pompoli F, Bonfiglio P, Horoshenkov KV, Khan A, Jaouen L, Bécot FX, et al. How reproducible is the acoustical characteri-zation of porous media? J. Acoustical society of America. 2017;141(2):945–55. doi:10.1121/1.4976087
12. [12] Ghorbani K, Hasani H, Zarrebini M, Saghafi R. An investiga-tion into sound transmission loss by polypropylene needle-punched nonwovens. Alexandria Engi-neering J. 2016;55(2):907-914. doi: 10.1016/j.aej.2016.02.012
13. [13] Bonfiglio P, Pompoli F, Horoshenkov KV, Rahim MIBSA, Jaouen L, Rodenas J, et al. How reproducible are methods to measure the dynamic viscoelastic properties of poroelastic media? Sound and Vibration J. 2018;428:26–43. doi: 10.1016/j.jsv.2018.05.006
14. [14] Shravage P, de’Sa K. Effect of macroscopic parameters on sound absorption and sound transmission loss of porous mate-rials. J. Acoustical Society of America. 2009;126(4_Supplement):2287. doi:10.1121/1.3249372
15. [15] dos Santos Pegoretti T. Environmental and sound analysis of the acoustic treatment of vehicle compartments [dissertation]. [sn]; 2014. doi:10.47749/T/UNICAMP.2014.942275
16. [16] Duval A, Crignon G, Goret M, Lemaire D, Prunet JB, Chanudet P. Ecofelt hybrid stiff NVH tunable insulator. SAE Tech Pap. 2018;2018-01-1494. doi:10.4271/2018-01-1494
17. [17] Yang M, Sheng P. Sound absorption structures: From porous media to acoustic metamaterials. Annu Rev Mater Res. 2017;47:83–114. doi:10.1146/annurev-matsci-070616-124032
18. [18] Ganesan P, Karthik T. Development of acoustic nonwoven materials from kapok and milkweed fibres. J Text Inst. 2016;107:477–82. doi:10.1080/00405000.2015.1045251
19. [19] Kabir MM, Wang H, Lau KT, Cardona F. Tensile properties of chemically treated hemp fibers as reinforcements for compo-sites. Compos Part B Eng. 2013;53:362–8. doi: 10.1016/j.compositesb.2013.05.048
20. [20] Yilmaz ND, Powell NB, Banks-Lee P, Michielsen S. Hemp-fiber based nonwoven composites: Effects of alkalization on sound absorption performance. Fibers Polym. 2012;13:915–22. doi:10.1007/s12221-012-0915-0
21. [21] Balčiūnas G, Žvironaitė J, Vėjelis S, Jagniatinskis A, Gaidučis S. Ecological, thermal and acoustical insulating composite from hemp shives and sapropel binder. Ind Crops Prod. 2016;91:286-94. doi: 10.1016/j.indcrop.2016.06.034
22. [22] Prömper E. Natural fibre-reinforced polymers in automotive interior applications. In: Wiley, editor. 2010. p. 423-36.
23. [23] Yousefzadeh B, Mahjoob M, Mohammadi N, Shahsavari A. An experimental study of sound transmission loss (STL) measurement techniques using an impedance tube. J. Acousti-cal Society of America. 2008;123(5):3119. doi:10.1121/1.2933032
24. [24] Kierzkowski M, Law H, Cotterill J. Benefits of reduced-size reverberation room testing. In: Proceedings of Acoustics 2017; 2017 Nov 19-22; Perth, Australia.
25. [25] Gelen M. Acoustic materials used in the automotive industry and examination of the effect of material properties on acous-tic parameters [master's thesis]. Institute of Science and Tech-nology; 2016. p. 978 625 7367 028.
26. [26] Labašová E, Ďuriš R. Measurement of the acoustic absorption coefficient by impedance tube. Research Papers Faculty of Materials Science and Technology Slovak University of Tech. 2019;27(45):94-101. doi:10.2478/rput-2019-0031
27. [27] Rey Tormos RM, Alba Fernández J, Bertó Carbó L, Gregori A. Small-sized reverberation chamber for the measurement of sound absorption. Mater Construcc. 2017;67(328):1-9. doi:10.3989/mc.2017.07316
28. [28] Santoni A, Bonfiglio P, Fausti P, Pompoli F. Computation of the Alpha Cabin sound absorption coefficient by using the fi-nite transfer matrix method (FTMM): inter-laboratory test on porous media. J.Vibration and Acoustics. 2021;143(2):021012. doi:10.1115/1.4048395
29. [29] ASTM C423. Standard test method for sound absorption and sound absorption coefficients by the reverberation room method. ASTM International; 2019. West Conshohocken, PA. doi: 10.1520/C0423-22
30. [30] Kierzkowski M, Law H, Cotterill J. Benefits of reduced-size reverberation room testing. In: Proceedings of ACOUSTICS 2017; 2017 Nov 19-22; Perth, Australia.
31. [31] Duval A, Rondeau JF, Dejaeger L, Sgard F, Atalla N. Diffuse field absorption coefficient simulation of porous materials in small reverberant rooms: finite size and diffusivity. In: 10th French Congress on Acoustics; 2010 Apr 12-16; Lyon, France.
32. [32] ASTM E261. Standard test method for measurement of nor-mal incidence sound transmission of acoustical materials based on the transfer matrix method. ASTM International. doi: 10.1520/C0423-22
33. [33] ISO 10534-2. Acoustics — Determination of sound absorp-tion coefficient and impedance in impedance tubes — Part 2: Transfer-function method. International Organization for Standardization; 1998. Switzerland.
34. [34] Wang Y, Li C, Chen X, Zhang C, Jin Q, Zhou G, et al. Sound absorption performance based on auxetic microstructure model: A parametric study. Mater Des. 2023;232:112130. doi: 10.1016/j.matdes.2023.112130
35. [35] Zent A, Long JT. Automotive sound absorbing material survey results. SAE Technical Paper. 2007;(No. 2007-01-2186). doi:10.4271/2007-01-2186
36. [36] Fan TY, Fan L. New dispersion formula and wave speed. Trans Beijing Inst Technol. 2010;(7):757-8.