مدلسازی، طراحی و تحلیل تعلیق صندلی مبتنی بر ساختار سختی منفی به منظور بهبود محیط ارتعاشی خلبان هلیکوپتر

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی مکانیک

2 گروه طراحی کاربردی دانشکده مهندسی مکانیک و انرژی دانشگاه شهید بهشتی

3 هیات علمی

4 مجتمع دانشگاهی هوافضا

چکیده

ارتعاشات انتقالی به سرنشین هلیکوپتر سرمنشاء بسیاری از مشکلات سلامتی می‌باشد. در این مقاله به منظور بهبود محیط ارتعاشی برای خلبان، یک مکانیزم تعلیق با ساختار سختی منفی پیشنهاد شده است. ساختار سختی منفی در ترکیب با ساختارهای سختی مثبت می‌تواند سختی دینامیکی کل سیستم و در نتیجه انتقال‌پذیری ارتعاش را کاهش دهد. ویژگی اصلی تعلیق پیشنهادی کاهش ارتعاشات انتقالی به سرنشین در کنار حفظ قابلیت باربرداری آن می‌باشد. در اینجا پس از ارائه یک مدل یکپارچه از سیستم تعلیق صندلی– سرنشین، روند طراحی پارامترهای سیستم تعلیق به منظور کاهش ارتعاشات انتقالی به سرنشین ارائه می‌شود. به منظور بررسی عملکرد سیستم تعلیق در حالت واقعی و نزدیک کردن نتایج به واقعیت، شبیه‌سازی‌ها بر اساس سیگنال واقعی اندازه‌گیری شده کف کابین هلیکوپتر بل-412 انجام شد. سپس با استفاده از استاندارد ایزو-2631 و معیارهای مرسوم، میزان ارتعاش صندلی و اجزای مختلف بدن خلبان ارزیابی گردید. نتایج نشان از عملکرد مناسب تعلیق طراحی شده است بطوریکه دامنه موثر و مقدار دوز ارتعاش ارتعاش عمودی در اجزای مختلف بدن سرنشین نشانگر کاهش متوسط حدود 40% دامنه ارتعاش می‌باشد. همچنین درجه ناراحتی از محدوده " ناراحت کننده" به "مقدار کمی ناراحتی" ارتقا یافت. نتایج همچنین نشان داد که طیف فرکانسی ارتعاش کف کابین به طیف فرکانسی روی صندلی و سر خلبان نزدیک بوده و عملاً مدولاسیون فرکانسی در طی مسیر ارتعاش از کف تا صندلی و سپس سر سرنشین اتفاق نمی‌افتد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Modeling, design and investigation of seat suspension based on negative stiffness structure to improve the vibration environment for helicopter pilots

نویسندگان [English]

  • ehsan davoodi 1
  • pedram safarpour 2
  • Mehdi Pourgholi 3
  • Mostafa Khazaee 4
1 school of mechanical engineering
2 Faculty of Mechanical & Energy Engineering,Shahid Beheshti University
3 Department of Electrical Engineering, Shahid Beheshti University
4 Aerospace Department
چکیده [English]

The vibration transmitted to helicopter aircrew is the main risk factor for their health. In this paper, a seat suspension based on a negative stiffness structure is proposed to improve the vibration environment for the aircrew. The main advantage of the proposed seat suspension is mitigation of vibration transmitted to occupant in the same time keeping the system payload capacity. Hereafter deriving the dynamic model of the proposed system, the occupant model is attached to achieve an integrated occupant-seat-suspension model. Next, the design procedure of suspension parameters is presented to reduce the vibration transmission. In order to reach realistic results, the simulations are performed using the measured data on Bell-412 helicopter cabin floor. Then, the level of vibrations transmitted to seat and pilot body parts are evaluated using ISO-2631 and common criteria. The results show the performance of system based on negative stiffness structure is good in terms of vibration reduction so that root mean square and vibration dose value of vertical vibration for pilot’s body parts are mitigated about 40% in comparison with cabin floor vibration. Also, according to ISO-2631, comfort level is upgraded from uncomfortable to a little uncomfortable which represents promotion of ride quality and improvement of vibration environment for the pilot. Furthermore, the results indicate that no frequency modulation happens in the vibration transfer path from the cabin floor to the pilot’s head.
 

کلیدواژه‌ها [English]

  • vibration damping
  • Negative stiffness structure
  • Seat suspension system
  • Whole body vibration
  • Pilot seat
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