Vibration characteristics of tractor seat cushion materials

Document Type: Research Paper

Authors

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

10.22099/iar.2020.32347.1330

Abstract

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.

Keywords


Article Title [Persian]

تحلیل ارتعاشی مواد بالشتک صندلی تراکتور

Authors [Persian]

  • 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 [Persian]

 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 [Persian]

  • راننده
  • فوم پلی یورتان
  • صندلی
  • اسفنج
  • ارتعاش کامل بدن
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