Ağır Hizmet Araçlarının Gürültü Kalkanı Parçasının Akustik ve Mekanik Dayanım Performansının İncelenmesi

Abstract

Kamyon, tır gibi ağır hizmet araçlarında en çok gürültü üreten yapı olan motor odasında oluşan ısı ve sesin izole edilmesi için bu yapının yakına yalıtım malzemesi olarak gürültü kalkanı konumlandırılmaktadır. Bu çalışmada, ağır hizmet araçlarında gürültü kalkanı olarak kullanılmak üzere, ses ve ısı üreten yapıya bakacak yönde konumlandırılan alt katmanda taş yünü, gürültü kalkanı parçasının mukavemet ve akustik performansını arttırmakla görevli üst katmanda PP/GF, GF/EP, GF/PET, Karbon/EP, fenolik keçe ve yapıştırıcı malzeme olarak PE film kullanılarak düz kalıpta, 190 °C sıcaklıkta ve 110 bar basınç altında kompozit sandviç yapılar oluşturulmuş ve bu yapıların empedans tüpünde ses yutum katsayıları ölçülerek akustik performansları birbiriyle karşılaştırılmıştır. Akustik performans test sonuçları incelendiğinde, ses yutum katsayısı (α) 1 değerine en yakın olan kompozit sandviç yapının dıştan içe doğru iki kaplama telası arasında PP/GF, PE film, taş yünü içeren malzeme kompozisyonu 1 olduğu tespit edilmiştir. Kalınlığın akustik performansa ve mukavemete etkisini incelemek üzere, en iyi akustik performansı gösteren malzeme kompozisyonu 1 ile 10 mm, 20 mm ve 30 mm kalınlıklarında üretilen numunelere akustik performans ve 3 nokta eğilme testleri uygulanmıştır. Elde edilen verilerden kalınlık arttıkça ses yutum kapasitesinin ve eğilme dayanımının arttığı tespit edilmiştir.

Keywords

• Akustik
• gürültü kalkanı
• kompozit
• mekanik dayanım
• yalıtım malzemesi

Investigation of Acoustic and Mechanical Strength Performance of the Noise Shield Part of Heavy-Duty Vehicles

Abstract

The motor compartment is the primary source of noise production in heavy-duty vehicles such as trucks and trailers due to the heat and sound generated. A noise shield is positioned in close proximity as insulation material to isolate these effects. This study specifically focuses on the use of insulation materials as a noise shield in heavy-duty vehicles. The lower layer addressing the structure producing heat and sound includes rock wool. The upper layer, responsible for enhancing strength and acoustic performance, consists of various materials, such as PP/GF, GF/EP, GF/PET, Carbon/EP, phenolic felt, and PE film as an adhesive material. These materials have been carefully selected to ensure optimal performance and meet the highest quality standards. Composite sandwich structures were created using these materials in a flat mold at a temperature of 190°C and a pressure of 110 bars. The acoustic performance of these structures was compared by measuring their sound absorption coefficients in an impedance tube. Upon examining the results of the acoustic performance tests, it was determined that Composition 1, including PP/GF, PE film, and rock wool between the two outer layers, had the sound absorption coefficient (α) closest to 1. To investigate the impact of thickness on both acoustic performance and strength, acoustic performance, and 3-point bending tests were conducted on samples produced with the best-performing material composition 1 at thicknesses of 10 mm, 20 mm, and 30 mm. The data obtained showed that as the thickness increased, so did the sound absorption capacity and bending strength.

Keywords

• Acoustic
• composite
• insulation material
• mechanical strength
• noise shield

References

1. E. Karaman, Recognition of vehicle models from engine sounds, Master’s Thesis Akdeniz University (2018) Antalya.
2. E. N. Keskin, Investigation the surface and acoustic properties of polyurethanes produced with different monomer mixing ratios, Master’s Thesis Bursa Uludağ University (2023) Bursa.
3. P. Mallick, Materials, design and manufacturing for lightweight vehicles, 2nd Edition, Woodhead Publishing, 2021.
4. N. Aktürk, O. Akdemir, İ. Üzkurt, Environmental noise caused by traffic lights timing and traffic volume, Journal of the Faculty of Engineering and Architecture of Gazi University 18 (1) (2003) 71–78.
5. D. R. Raichel, The science and applications of acoustics, 2nd Edition, Springer, Berlin, 2006.
6. E. Boztepe, Investigation of relation between acoustic properties and heat conduction in automotive interior trim materials, Master’s Thesis Bursa Uludağ University (2018) Bursa.
7. G. Shen, Vehicle noise, vibration, and sound quality, Warendale, Pensnsylvania, 2012.
8. B. M. Spessert, H. S. Kochanowski, Diesel engine noise emission, in: K. Mollenhauer, H. Tschoeke (Eds.), Handbook of Diesel Engines, Springer, Berlin, Heidelberg, 2010, Ch. 16, pp. 487–504.

9. P. B. Metinoğlu, Effect of material and design in noise shields used in trucks, Master’s Thesis İstanbul Technical University (2014) İstanbul.
10. M. A. Balcı, Research of the effect of engine beauty covers on vehicle’s interior and exterior noises, Master’s Thesis Ege Üniversitesi (2022) İzmir.
11. X. Wang, Vehicle noise and vibration refinement, Woodhead Publishing, Cambridge, 2010.
12. M. Tuzla, Structural optimization of automobile upper components, Master’s Thesis Bursa Uludağ Üniversitesi (2022) Bursa.
13. F. A. Presezniak, L. Sofia, A Noise Shield Arrangement Comporising a Thermally Conductive Element – European Patent Application (EP4046875A1) (2021), https://worldwide.espacenet.com/patent/search/family/074672147/publication/EP4046875A1?q=EP4046875A1, Accessed 17 Nov 2023.
14. Y. Ulcay, M. Akyol, R. Gemci, Investigation of different cure methods on the interfacial strength of polymer based fiber reinforced composites, Uludağ University Journal of The Faculty of Engineering and Architecture 7 (1) (2002) 93–116.
15. A. Zent, J. T. Long, Automotive sound absorbing material survey results, Society of Automotive Engineering Noise and Vibration Conference and Exhibition, Illinois, 2007.
16. C. N. Wang, J. H. Torng, Experimental study of the absorption characteristics of some porous fibrous materials, Applied Acoustics 62 (4) (2001) 447–459.
17. Ü. Esendemir, A. Y. Caner, Experimental investigations on the impact behavior of laminated composite materials, Süleyman Demirel University Journal of Natural and Applied Sciences 22 (1) (2018) 207–215.
18. O. Özdemir, H. Kandaş, Thickness and temperature effects on the impact behavior of glass fiber reinforced polypropylene composites, Journal of Textiles and Engineer 25 (110) (2018) 103–112.
19. İ. Aydın, Measurement of sound absorption coefficients on the automotive isolation materials and determining the optimum material thickness, Master’s Thesis Gazi Üniversity (2008) Ankara.
20. T. Doğru, Investigation of relation between acoustic properties and heat conduction in automotive interior trim materials, Master’s Thesis Bursa Uludağ Üniversity (2020) Bursa.
21. A. Kundt, Acoustic experiments, The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science 35 (4) (1866) 41–48.
22. İ. Kocaoğlu, Otomotiv Sektöründe Kompozit Malzeme Kullanımı (2021), https://kalkinmaguncesi.izka.org.tr/index.php/2021/06/17/otomotiv-sektorunde-kompozit-malzeme-kullanimi/, Accessed 17 Nov 2023.
23. M. Tanoğlu, M. Toğulga, Kompozit malzemeler ve jeotermal uygulamaları, Jeotermal Enerji Semineri (2005) 407–419.
24. W. A. de Morais, S. N. Monteiro, J. R. M. d’Almeida, Effect of the laminate thickness on the composite strength to repeated low energy impacts, Composite Structures 70 (2005) 223–228.