Evaluation of Nonuniformity of Elastic Properties of Sheets Made from Closed-Сell Polyolefin Foams by Acoustic Method

The widespread use of polyolefin foams in strategically important industries is due to their high thermal, sound and vibration insulation properties. The aim of the work was to evaluate the non-uniformity of elastic properties over the area of sheets of polyolefin foams of various types using the acoustic non-contact shadow amplitude method of testing and confirmation by the structural analysis method.

The article presents the developed installation and a new method of non-contact acoustic testing of sheets made of closed-cell polyolefin foams based on recording the amplitude of the pulse that passed through the sheet and allowing to assess to the unevenness of its elastic properties during scanning. Studies of uneven elastic properties were carried out on sheets of closed-cell polyolefin foams of the ISOLON 500 and ISOLON 300 brands which differ in material and manufacturing technology (technique of cross-linking, method and multiplicity of foaming).

It is shown that the absolute amplitude of the signal and its spread relative to the average value is affected by the structure of the foam polyolefin material and its heterogeneity over the area of the studied sheet determined by the production technology which is confirmed visually using microscopy.

Studies have shown the effect on the indications unevenness of the method of obtaining and the apparent density of the material. It is shown that the most uneven elastic properties and structure belong to sheets of polyolefin foam obtained by chemical cross-linking technology (the unevenness of Δ was 6.5 %). Among the physically cross-linked sheets of polyolefin foam the most uniform in structure and elastic properties are samples made of ethylene vinyl acetate with Δ = 3.8 %, as well as sheets with a high foaming rate (Δ = 3.9 %). The unevenness of structure of the studied sheets of polyolefin foams was confirmed by optical microscopy of sections in two mutually perpendicular directions.

1. Kolbun N.V., Petrov S.N., Prudnik A.M. Electromagnetic and acoustic characteristics of multilayer materials for integrated protection systems. Reports of the Belarusian State University of Informatics and Radioelectronics, 2009, no. 3(41), pp. 79‒85.

2. Kim B.-S., Seong Y., Park J. Modified twothickness method for measurement of the acoustic properties of porous materials. Applied Acoustics, 2019, vol. 146, pp. 184‒189. DOI: 10.1016/j.apacoust.2018.10.033

3. Tiuca A.-E., Vermeşana H., Gabora T., Vasileb O. Improved sound absorption properties of polyurethane foam mixed with textile waste. Energy Procedia, 2016, vol. 85, pp. 559–565. DOI: 10.1016/j.egypro.2015.12.245

4. Zhanga C., Lib J., Hua Z., Zhua F., Huanga Y. Correlation between the acoustic and porous cell morphology of polyurethane foam: Effect of interconnected porosity. Materials & Design, 2012, vol. 41, pp. 319‒325. DOI: 10.1016/j.matdes.2012.04.031

5. Chen S., Zhu W., Cheng Y. Multi-Objective Optimization of Acoustic Performances of Polyurethane Foam Composites. Polymers, 2018, vol. 10, 788 p DOI: 10.3390/polym10070788

6. Scarpa F., Bullough W.A., Lumley P. Rends in acoustic properties of iron particle seeded auxetic polyurethane foam. Journal of Mechanical Engineering Science, 2004, vol. 218, iss. 2, pp. 241‒244. DOI: 10.1243/095440604322887099

7. Huangab K., Daiab L., Fanc Y. Applied Acoustics Characterization of noise reduction capabilities of porous materials under various vacuum conditions. Applied Acoustics, 2020, vol. 161, pp. 107‒155. DOI: 10.1016/j.apacoust.2019.107155

8. Sgarda F., Castelb F., Atallac N. Use of a hybrid adaptive finite element/modal approach to assess the sound absorption of porous materials with meso-heterogeneities. Applied Acoustics, 2011, vol. 72, iss. 4, pp. 157‒168. DOI: 10.1016/j.apacoust.2010.10.011

9. Chekkal I., Remillat C., Scarpa F. Acoustic properties of auxetic foams. WIT Transactions on The Built Environment, 2012, vol. 124, pp. 119‒129. DOI: 10.2495/HPSM120111

10. Sua J., Zhenga L., Dengab Z. Study on acoustic properties at normal incidence of three-multilayer composite made of glass wool, glue and polyurethane foam. Applied Acoustics, 2019, vol. 156, pp. 319‒326. DOI: 10.1016/j.apacoust.2019.07.016

11. Sung G., Kim J.H. Influence of filler surface characteristics on morphological, physical, acoustic properties of polyurethane composite foams filled with inorganic fillers. Composites Science and Technology, 2017, vol. 146, pp. 147‒154. DOI: 10.1016/j.compscitech.2017.04.029

12. Shuming C., Yang J. The acoustic property study of polyurethane foam with addition of bamboo leaves particles. Polymer composites, 2018, vol. 39, iss. 4, pp. 1370‒1381. DOI: 10.1002/pc.24078

13. Çelebi S., Küçük H. Acoustic Properties of TeaLeaf Fiber Mixed Polyurethane Composites. Cellular Polymers, 2012, vol. 31, iss. 5, pp. 241‒256.DOI: 10.1177/026248931203100501

14. Etchessahar M., Sahraoui S., Benyahia L., Tassin J.F. Frequency dependence of elastic properties of acoustic foams. The Journal of the Acoustical Society of America, 2005, vol. 117, iss. 3, p. 1114. DOI: 10.1121/1.1857527

15. Kumar R., Jin Y., Marre S., Poncelet O., Brunet T., Leng J., Mondain-Monval O. Drying kinetics and acoustic properties of soft porous polymer materials. Journal of Porous Materials, Springer Verlag, inPress, 2020. DOI: 10.1007/s10934-020-00987-w

16. Lenkov S.V., Molin S.M., Kopytov A.G. Resonance measurement technique for viscoelastic properties of damping materials of the porous closed cellular pe foam type. Russian Journal of Nondestructive Testing, 2014, vol. 50, iss. 3, pp. 180‒185 (in Russian). DOI: 10.1134/S1061830914030061

17. Glushkov E.V., Glushkova N.V., Fomenko S.I. Influence of porosity on characteristics of rayleigh-type waves in multilayered half-space. Acoustical Physics, 2011, vol. 57, no. 2, pp. 230‒240 (in Russian). DOI: 10.1134/S1063771011020059

18. Abdessalam H., Abbès B., Abbès F., Li Y., Guo Y.-Q. Prediction of acoustic properties of polyurethane foams from the macroscopic numerical simulation of foaming process. Applied Acoustics, 2017, vol. 120, pp. 129–136. DOI: 10.1016/j.apacoust.2017.01.021

19. Pauzin S.A. Аccounting for anisotropy in the design of sound insulation of internal fences of high-rise buildings. Privolzhsky nauchnyj zhurnal, 2019, no. 4, pp. 40‒45.

20. Pasmanik L.A., Kamyshev A.V., Radostin A.V., Zaitsev V.Yu. Parameters of acoustic inhomogeneity for non-destructive evaluation of the influence of manufacturing technology and operational damage on the metal structure. Flaw detection, 2020, no. 12, pp. 24‒36. DOI: 10.31857/S0130308220120039

21. Zlobin D.V., Volkova L.V., Bogdan O.P., Zemskov T.I., Kazantsev S.V. Universal experimental setup for acoustic research. Intelligent Systems in Production, 2020, vol. 18, no. 2, pp. 28‒36. DOI: 10.22213 / 2410-9304-2020-2-28-36

22. Bogdan O.P., Muravyeva O.V., Platunov A.V., Rysev D.S. Investigation of the characteristics of foam polyethylene sheets by acoustic methods. Vestnik IzhSTU imeni M. T. Kalashnikov, 2020, vol. 24, no. 2, pp. 61‒68. DOI: 10.22213/2413-1172-2020-2-61-68

23. Bogdan O.P., Zlobin D.V., Muravieva O.V., Muraviev V.V., Volkova L.V. Acoustic and Eddy Current Methods of Nondestructive Testing of Thermally Expanded Graphite Sheets. IOP Conference Series: Earth and Environmental Science, 2020, no. 543(1), pp. 012033. DOI: 10.1088/1755-1315/543/1/012033