Vibration characteristics of tractor seat cushion materials

Document Type : Research Paper


1 Mechanical Engineering of Biosystems, Shahrekord University, Iran

2 Department of Mechanical Engineering of Biosystems,faculty of Agriculture, of Shahrekord University , Iran

3 Mechanical Engineering of Biosystems, Arak University, Iran



Operators of agricultural machinery are exposed to an extensive range of indirect vibrations through the seats, which gradually causes chronic damages. One of the ways to reduce the vibrations imposed on the operators is to use appropriate materials in tractor seat cushion. The present study was carried out in order to select appropriate foam or sponge and investigate different factors in reducing vibrations imposed on operator’s body so as to promote drivers health and enhance their working efficiency. Vibration experiments were performed at different accelerations on foam and sponge materials at different thicknesses and densities for different occupant masses, and the input and output acceleration signals were recorded and analyzed. Using the analysis of variance, analysis of the mean squares of the input and output acceleration, the type of material used in the seat cushion and the effect of different factors on them were investigated. The results showed that in reducing vibrations, sponge for mass of 90 kg and more and foam for mass of 75 kg and less were more efficient. The sponge was also suitable for acceleration of excitation above 6 ms-2and foam for acceleration of excitation above 3 ms-2 and below. Therefore, according to the working conditions of agricultural machines and anthropometric characteristics of Iranian drivers and the appropriate suitable thickness of the seat cushion (6-8 cm), it is recommended that their seat cushion be made of a combination of foam and sponge with high density and thickness of 8 cm.


Article Title [فارسی]

تحلیل ارتعاشی مواد بالشتک صندلی تراکتور

Authors [فارسی]

  • ندا عسگری فر 1
  • علی ملکی 2
  • مجید لشگری 3
1 گروه مهندسی مکانیک بیوسیستم، دانشگاه شهرکرد، ایران
2 گروه مهندسی مکانیک بیوسیستم، دانشکده کشاورزی ، دانشگاه شهرکرد، شهرکرد، ایران
3 گروه مهندسی مکانیک بیوسیستم،‌ دانشگاه اراک، اراک، ج، ا، ا، ایران
Abstract [فارسی]

 رانندگان ماشین­های کشاورزی در معرض محدوده وسیعی از ارتعاشات غیرمستقیم، از طریق صندلی آن هستند و به مرور زمان آسیب‌های دائمی برای آن­ها به‌وجود می‌آید. یکی از راه­های کاهش ارتعاشات منتقل شده، استفاده از مواد مناسب برای نشستگاه صندلی تراکتور است. مطالعه حاضر به منظور انتخاب فوم یا اسفنج مناسب و بررسی عوامل مختلف در کاهش لرزشهای وارد شده به بدن اپراتور به منظور ارتقاء سلامت رانندگان و افزایش کارآیی کار آنها انجام شده است.  آزمایش‌های ارتعاشی در شتاب‌های مختلف روی دو ماده فوم و اسفنج در ضخامت­ها و دانسیته­های مختلف برای جرم­‌های متفاوت سرنشین انجام شد و سیگنال‌های شتاب­های ورودی و خروجی ثبت و تجزیه و تحلیل ­شدند. با استفاده از آنالیز تحلیل واریانس میانگین مربعات شتاب ورودی و خروجی، نوع ماده مورد استفاده در نشستگاه صندلی و اثر عوامل مختلف بر آن­ها بررسی­شد.نتایج نشان داد که در کاهش ارتعاشات اسفنج برای جرم 90 کیلوگرم و بیشتر و فوم برای جرم 75 کیلوگرم و کمتر، کارایی بالاتری داشتند. همچنین اسفنج، برای شتاب تحریک بالاتر از 6 متر بر مجذورثانیه و فوم، برای شتاب تحریک 3 متر بر مجذورثانیه و پایین‌تر مناسب بود. لذا با توجه به شرایط کاری ماشین‌های کشاورزی و خصوصیات انتروپومتریکی رانند‌ه‌های ایرانی و محدود مناسب ضخامت کوسن صندلی (6-8 سانتیمتر)، پیشنهاد می‌شود کوسن صندلی آن‌ها به صورت ترکیبی از فوم و اسفنج با دانسیته‌ بالا و ضخامت 8 سانتیمتر ساخته شود.

Keywords [فارسی]

  • راننده
  • فوم پلی یورتان
  • صندلی
  • اسفنج
  • ارتعاش کامل بدن
Azrah, K., Khavanin, A., Sharifi, A., Safari, Z., & Mirzaei, R. (2014). Assessment of metro passengers’ convenience while sitting and standing in confrontation with whole-body vibration. International Journal of Occupational Hygiene, 6(4), 192-200.
Barač, Ž., Plaščak, I., Jurić, T., Jurišić, M., Zimmer, D., Vidaković, I., & Marković, M. (2018). Operator’s whole body vibrations dependent of agrotechnical surface, speed of movement and seat upholstery. Tehnički Glasnik, 12(2), 68-73.
Barikani, D. (2005). Polyurethane: Chemistry, Properties, Application, Timeliness. Tehran: Iran Polymer Petrochemical Research Institute. (In Persian)
Barikani, D. (2007). Polyurethane rigid foams. Tehran: Polymer Science and Engineering Association of Iran. (In Persian)
Chaffin, D. B., Andersson, G. B., & Martin, B. J. (2006). Occupational biomechanics. Hoboken, New Jersey: John Wiley & Sons.
Corsaro, R. D., & Sperling, L. H.. (1990). Sound and vibration damping with polymers. Washington, DC: American Chemical Society.
Cvetanovic, B., Cvetković, D., Praščević, M., Cvetković, M., & Pavlović, M. (2017). An analysis of the impact of agricultural tractor seat cushion materials to the level of exposure to vibration. Journal of Low Frequency Noise, Vibration and Active Control, 36(2), 116-123.
Demec, M., Lukic, J., & Milic, K. (2002). Some aspects of the investigation of random vibration influence on ride comfort. Journal of Sound and Vibration, 253(1), 109-129.
Drakopoulos, D. (2007). A review of the current seat technologies in agricultural tractors. Department of biosystems engineering university of Manitoba. Winnipeg, Canada. Retrieved from:
Fairley, T. E., & Griffin, M. J. (1990). The apparent mass of the seated human body in the fore-and-aft and lateral directions. Journal of Sound and Vibration, 139(2), 299-306.
Ferrarin, M., Andreoni, G., & Pedotti, A. (2000). Comparative biomechanical evaluation of different wheelchair seat cushions. Journal of Rehabilitation Research and Development, 37(3), 315-324.
Griffin, M. J., Whitham, E. M., & Parsons, K. C. (1982). Vibration and comfort I. Translational seat vibration. Ergonomics, 25(7), 603-630.
Koley, S., Sharma, L., & Kaur, S. (2010). Effects of occupational exposure to whole-body vibration in tractor drivers with low back pain in Punjab. The Anthropologist, 12(3), 183-187.
Lamont, H. S., Cramer, J. T., Bemben, D. A., Shehab, R. L., Anderson, M. A., & Bemben, M. G. (2011). Effects of a 6-week periodized squat training with or without whole-body vibration upon short-term adaptations in squat strength and body composition. The Journal of Strength & Conditioning Research, 25(7), 1839-1848.
Lings, S., & Leboeuf-Yde, C. (2000). Whole-body vibration and low back pain: A systematic, critical review of the epidemiological literature 1992–1999. International Archives of Occupational and Environmental Health, 73(5), 290-297.
Machado, A., García- López, D., González- Gallego, J., & Garatachea, N. (2010). Whole- body vibration training increases muscle strength and mass in older women: a randomized- controlled trial. Scandinavian Journal of Medicine & Science in Sports, 20(2), 200-207.
Makhsous, M., Hendrix, R., Crowther, Z., Nam, E., & Lin, F. (2005). Reducing whole-body vibration and musculoskeletal injury with a new car seat design. Ergonomics, 48(9), 1183-1199.
Maleki, A., & Mohtasebi, S. S. (2014). Natural frequency analysis of tractor operator's body parts. Research in Rehabilitation Sciences, 10(2), 250-268.
Mansfield, N. J. (2004). Human response to vibration. Boca Raton, FL: CRC press.
Mansfield, N. J., & GRIFFIN, M. J. (2002). Effects of posture and vibration magnitude on apparent mass and pelvis rotation during exposure to whole-body vertical vibration. Journal of Sound and Vibration, 253(1), 93-107.
McBride, J. M., Nuzzo, J. L., Dayne, A. M., Israetel, M. A., Nieman, D. C., & Triplett, N. T. (2010). Effect of an acute bout of whole body vibration exercise on muscle force output and motor neuron excitability. The Journal of Strength & Conditioning Research24(1), 184-189.
Mehta, C. R., & Tewari, V. K. (2000). Seating discomfort for tractor operators–a critical review. International Journal of Industrial Ergonomics, 25(6), 661-674.
Mircheski, I., Kandikjan, T., & Simonovski, P. (2010). Virtual testing and experimental verification of seat comfort in driver’s seat for passenger automobile. Ss Cyrill & Methodius University, Faculty of Mechanical Engineering, Karpos II-bb, 1000. Retrieved from:
Standard, I. (1997). ISO2631 1. Mechanical vibration and shock; Evaluation of human exposure to whole body vibration in the working environment; Part 1 General requirements.  Geneva: International Standard Organization.
Tiemessen, I. J., Hulshof, C. T., & Frings-Dresen, M. H. (2007). An overview of strategies to reduce whole-body vibration exposure on drivers: A systematic review. International Journal of Industrial Ergonomics, 37(3), 245-256.
Tsai, C. L., & Lin, J. C. (2011). The effect of whole- body vibration stimulus using varying oscillation amplitudes on lower body power. Medicine & Science in Sports & Exercise, 43(5), 799-813.
Turner, A. P., Sanderson, M. F., & Attwood, L. A. (2011). The acute effect of different frequencies of whole-body vibration on countermovement jump performance. The Journal of Strength & Conditioning Research, 25(6), 1592-1597.