مهندسی مکانیک مدرس

مهندسی مکانیک مدرس

بررسی تجربی ارتعاشات وارد بر بدن خلبانان بالگرد با مدلسازی رفتار دینامیکی غیرخطی بالشتک‌ صندلی پلی‌یورتان

نوع مقاله : مقاله پژوهشی

نویسندگان
سید محمد کمالی 1
علی نوری 1
حشمت الله محمد خانلو 1
هادی صبوری 2
1 دانشکده مهندسی هوافضا، دانشگاه علوم و فنون هوایی شهید ستاری، تهران، ایران
2 گروه مهندسی مکانیک، دانشکده مهندسی، دانشگاه خوارزمی، تهران، ایران
10.48311/mme.2026.119007.82968
چکیده
ارتعاشات ناشی از پرواز و مانورهای بالگرد، به‌ویژه در محدوده فرکانسی پایین (۰ تا ۲۰ هرتز)، می‌توانند موجب بروز تنش‌های فیزیکی بلندمدت و کاهش راحتی خلبان شوند. اگرچه سامانه‌های تعلیق صندلی نقش مؤثری در کاهش انتقال ارتعاشات ایفا می‌کنند، عملکرد بالشتک صندلی به‌عنوان یکی از عوامل کلیدی در بهبود راحتی پرواز شناخته می‌شود. در این پژوهش، یک رویکرد یکپارچه محاسباتی–تجربی برای بررسی تأثیر بالشتک‌های غیرخطی پلی‌اورتان پلی‌اتر بر راحتی خلبان بالگرد ارائه شده است. به‌منظور ارزیابی پاسخ بیودینامیکی، ابتدا یک مدل چهار درجه آزادی توسعه یافت و سپس با افزودن دینامیک بالشتک صندلی، مدل به یک سامانه پنج درجه آزادی گسترش داده شد. پارامترهای سختی و میرایی خطی و غیرخطی بالشتک‌ها از طریق آزمون‌های تجربی تحلیل مودال تعیین و برای اعتبارسنجی مدل‌ها به‌کار گرفته شدند. نتایج نشان داد که در نظر گرفتن رفتار غیرخطی بالشتک صندلی، دقت پیش‌بینی شاخص‌های انتقال‌پذیری، امپدانس مکانیکی و جرم ظاهری را به‌طور قابل‌توجهی بهبود می‌بخشد و انطباق مناسبی با داده‌های تجربی دارد. یافته‌های این مطالعه بر اهمیت مدل‌سازی دقیق رفتار غیرخطی بالشتک‌های صندلی در طراحی سامانه‌های مؤثر ایزولاسیون ارتعاش و ارتقای راحتی خلبانان بالگرد تأکید می‌کند
کلیدواژه‌ها
بالشتک صندلی بالگرد
راحتی سرنشین
ارتعاشات کل‌بدنی
انتقال‌پذیری
میرایی و سختی غیرخطی
موضوعات

عنوان مقاله English

Experimental Investigation of Pilot Whole-Body Vibrations in Helicopters Using Nonlinear Dynamic Modeling of Polyurethane Seat Cushion

نویسندگان English

seyed mohammad Kamali 1
Ali nouri 1
Heshmat allah mohammad Khanlo 1
Hadi Saouri 2
1 Department of Aerospace Engineering, Shahid Sattari Aeronautical University of Science and Technology, Tehran, Iran
2 Faculty of Engineering, Department of Mechanical Engineering, Kharazmi University, Tehran, Iran
چکیده English

Exposure to helicopter vibrations during flight and maneuvers can lead to long-term physical strain on pilots, particularly in the low-frequency range (0–20 Hz). While seat suspensions provide some vibration isolation, the seat cushion plays a critical role in overall ride comfort. This study presents an integrated computational and experimental investigation of nonlinear polyether polyurethane seat cushions and their effect on helicopter pilot comfort. Ride comfort is initially analyzed using a 4-DOF biodynamic model and subsequently extended to a 5-DOF model to explicitly include seat cushion dynamics. Experimental measurements of both linear and nonlinear stiffness and damping properties are conducted through modal analysis tests, providing data for model validation. Results demonstrate that considering nonlinear cushion behavior significantly improves predictions of transmissibility, mechanical impedance, and apparent mass, showing strong agreement with experimental observations. The findings highlight the importance of accurate nonlinear modeling for the design of seat cushions that enhance vibration isolation and improve overall pilot ride comfort

کلیدواژه‌ها English

Cushion
ride comfort
Whole body vibration
Transmissibility
Nonlinear Damping and Stiffness
[1] P. Mondal, S. Arunachalam, Finite Element Modelling of Car Seat with Hyperelastic and Viscoelastic Foam Material Properties to Assess Vertical Vibration in Terms of Acceleration, Engineering 12, 2020, doi: 10.4236/eng.2020.123015.
[2] Zhu, S., Dong, R., Lu, Z., Guo, Y., Liu, Z., & Liu, H. A finite element method study of the effect of vibration on the dynamic biomechanical response of the lumbar spine. Clinical Biomechanics, 2024. 111, 106164. doi: 10.1016/j.clinbiomech.2023.106164.
[3] Yin, W., Ding, J., & Qiu, Y. Nonlinear Dynamic Modelling of a Suspension Seat for Predicting the Vertical Seat Transmissibility. Mathematical Problems in Engineering, 2021, Article ID 3026108, 1–10,2021. doi: 10.1155/2021/3026108.
[4] Saengwong-ngam, R., & Kitazawa, H. (۲۰۲۴). Cushion performance of eco-friendly natural rubber latex foam composite with bamboo leaf fiber for impact protection of guava. Postharvest Biology and Technology, 208, 112663. doi: 10.1016/j.postharvbio.2023.112663.
[5] Bagheri, Mohammad Reza, et al. "Pareto optimization of a three-dimensional full vehicle suspension model using multi-objective genetic algorithm." Modares Mechanical Engineering, 1971-1978, 2019.
[6] khavanin A, Health risk assessment due to exposure to whole body vibration using ISO 2631-1 and BS 6841 standards, 2013, doi:  10.7508/jrh.2016.04.002.
[7] J. Marzban-Rad, A. Afkar, and M. Rajabpour, “A review study of the vibrations caused to the human sitting and providing an optimal biomechanical model of the car occupant using genetic algorithm,” J. Vib. Eng. Technol., vol. 6, no. 6, pp. 489–503, Dec. 2018, doi: 10.1007/s42417-018-0054-z.
[8] T. E. Fairley and M. J. Griffin, “The apparent mass of the seated human body: Vertical vibration,” J. Biomech., vol. 22, no. 2, pp. 81–94, 1989, doi: 10.1016/0021-9290(89)90031-6.
[9] P.M. Bongers, C.T.J. Hulshof, L. Dljkstra, H.C. Boshuizen, H.J.M. Groenhout, E. Valken, Back pain and exposure to whole body vibration in helicopter pilots,1990, doi: 10.1080/00140139008925309.
[10] C. Corbridge, M.J. Grifftn, Vibration and comfort: Vertical and lateral motion in the range 0·5 to 5·0 Hz, Ergonomics 29 ,1986, doi: 10.1080/00140138608968263.
[11] P.E. Boileau, A Study of Secondary Suspensions and Human Driver Response to Whole-Body Vehicular Vibration and Shock, 1995, https://api.semanticscholar.org/CorpusID:107673735.
[12] M.J. Griffin, Measurement, evaluation, and assessment of occupational exposures to hand-transmitted vibration, 1997, doi: 10.1136/oem.54.2.73.
[13] P.-E. Boileau, S. Rakheja, Whole-body vertical biodynamic response characteristics of the seated vehicle driver Measurement and model development, 1998, doi: 10.1016/S0169-8141(97)00030-9.
[14] V. A. Atindana et al., “Experimental design and optimization of pneumatic low-frequency driver seat for off-road vehicles: quasi-zero negative stiffness and gray wolf optimization algorithm,” Journal of the Brazilian Society of Mechanical Sciences and Engineering, vol. 45, no. 9, p. 502, 2023. doi: 10.1007/s40430-023-04391-8.
[15] S.A. Pankoke S., Latest development in occupant simulation techniques related to seating comfort and human response and human response to vibration: finite element occupant model CASIMIR, United Kingdom Conference on Human Responses to Vibration 2008, doi:10.4271/2007-01-2459.
[16] C. Zhang, Y. Zhao, Y. Shen, and D. Li, “The modeling and analysis of vibration response with airdrop vehicle in landing process,” Journal of the Brazilian Society of Mechanical Sciences and Engineering, vol. 46, no. 6, p. 345, 2024. doi: 10.1007/s40430-024-04913-y.
[17] A.M.A. Soliman, Measurement and modelling of the y-direction apparent mass of sitting human body-cushioned seat system, J Sound Vib 322 ,2009, doi: 10.1016/j.jsv.2008.11.002.
[18] G.J. Stein, P. Múčka, R. Chmúrny, B. Hinz, R. Blüthner, Measurement and modelling of x-direction apparent mass of the seated human body-cushioned seat system, J Biomech 40 2007, doi: 10.1016/j.jsv.2008.11.002.
[19] Y. Chen, V. Wickramasinghe, D. Zimcik, Development and evaluation of hybrid seat cushions for helicopter aircrew vibration mitigation, in: J Intell Mater Syst Struct, SAGE Publications Ltd, 2015: pp. 1633–1645. doi: 10.1177/1045389X14566522.
[20] Milanese C, Cavedon V, Sandri M, Tam E, Piscitelli F, Boschi F, Zancanaro C. Metabolic effect of bodyweight whole-body vibration in a 20-min exercise session: A crossover study using verified vibration stimulus. PLoS One. 2018 Jan 31;13(1): e0192046. doi: 10.1371/journal.pone.0192046.
[21] S.A. Adam, N.A.A. Jalil, K.A.M. Razali, Y.G. Ng, M.F. Aladdin, Mathematical Model of Suspension Seat-Person Exposed to Vertical Vibration for Off-Road Vehicles, 2019, doi: 10.1016/j.jbiomech.2018.11.003.
[22] Ruoxun, Fan, Jie Liu, and Jun Liu. "Finite element investigation on the dynamic mechanical properties of low-frequency vibrations on human L2–L3 spinal motion segments with different degrees of degeneration." Medical and Biological Engineering and Computing 58.12 3003-3016. 2020. doi: 10.1007/s11517-020-02263-0.
[23] Rezaee, Mousa. "On the effects of Passenger Seat Characteristics on the Ride Comfort of a Vehicle under the Random Excitation." Modares Mechanical Engineering, 43-55, 2011.
[24] Wang, Ziyi, et al. "Pilot workload measurement model based on task complexity analysis." International Journal of Industrial Ergonomics 104, 103637, 2024. doi: 10.1016/j.ergon.2024.103637.
[25] Yang, Sheng-Chieh, and Yun-Ju Lee. "Optimizing E-bike controls for human-bike interaction to enhance riding experience and efficiency." International Journal of Industrial Ergonomics 104,
 [26] Li, Wenhao, et al. "Biomechanical response of the musculoskeletal system to whole body vibration using a seated driver model." International Journal of Industrial Ergonomics 45 91-97.2015. doi: 10.1016/j.ergon.2014.12.006.
[27] A. Heydarian, X. Wang, A Modal Analysis of Whole-Body Vertical Vibration, Using A Finite Element Model of The Human Body, 1997, doi: 10.1006/jsvi.1996.0674.
[28] Mohandesi, N., M. Fadaee, and M. Talebitooti. "Nonlinear vibration of simply supported star-shaped auxetic cylindrical shell: N. Mohandesi et al." Archive of Applied Mechanics 95.8, 2025. doi: 10.1007/s00419-025-02913-5.
[29] Y. Cho, Y.-S. Yoon, Biomechanical model of human on seat with backrest for evaluating ride quality, 2001, doi: 10.1016/S0169-8141(00)00061-5.
[30] Dong, Zilong, et al. "Research on the design, performance and engineering application of a novel suspension structure." Archive of Applied Mechanics 95.8, 2025. doi: 10.1007/s00419-025-02884-7.
[31] T. Yoshimura, K. Nakai, G. Tamaoki, Multi-body Dynamics Modelling of Seated Human Body under Exposure to Whole-Body Vibration, 2005, doi: 10.2486/indhealth.43.441.
[32] S. Rakheja, R.G. Dong, S. Patra, P.É. Boileau, P. Marcotte, C. Warren, Biodynamics of the human body under whole-body vibration: Synthesis of the reported data, Int J Ind Ergon 40 ,2010, doi: 10.1016/j.ergon.2010.06.005.
[33] Corbridge, C., M. J. Griffin, and P. R. Harborough. "Seat dynamics and passenger comfort." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 203.1 57-64. 1989.DOI: doi: 10.1243/PIME_PROC_1989_203_209_0.
[34] G.J. Gouw, S. Rakheja, S. Sankar, Y. Afework, Increased Comfort and Safety of Drivers of Off-Highway Vehicles Using Optimal Seat Suspension, 1990, doi: 10.4271/901646.
[35] S.D. Smith, The Effects of Prototype Helicopter Seat Cushion Concepts on Human Body Vibration Response, 1997, doi: 10.1177/026309239801700105.
[36] Yin, W., Ding, J., & Qiu, Y. (2021). Nonlinear Dynamic Modelling of a Suspension Seat for Predicting the Vertical Seat Transmissibility. Mathematical Problems in Engineering, 2021, Article ID 3026108. doi: 10.1155/2021/3026108.
[37] Y. Wan, J.M. Schimmels, Optimal Seat Suspension Design Based on IVI Simulated Subjective Response, 1997, doi: 10.1115/1.2798287.
[38] A. Tamer, V. Muscarello, P. Masarati, G. Quaranta, Evaluation of vibration reduction devices for helicopter ride quality improvement, Aerospace Sci Technol 95 ,2019, doi: 10.1016/j.ast.2019.105456.
[39] Hassan, Azmi Mohammad, et al. "The Effect of Preload, Density and Thickness on Seat Dynamic Stiffness." Pertanika Journal of Science & Technology 31.3 ,2023, DOI: doi: 10.47836/pjst.31.3.08.
[40] Singh, R., Davies, P., & Bajaj, A. K. Identification of Nonlinear and Viscoelastic Properties of Flexible Polyurethane Foam. Nonlinear Dynamics, 319-340, 2003. doi: 10.1023/B:NODY.0000013511.07097.87.
[41] Singh, R., Davies, P., & Bajaj, A. K. Experimental Techniques and Identification of Nonlinear and Viscoelastic Properties of Flexible Polyurethane Foam. Nonlinear Dynamics, 281-313. 2000, doi: 10.1023/A:1008302208269.
[42] Briody, C. The Characterization and Numerical Modelling of Viscoelastic Polyurethane Foams for Use in Custom Wheelchair Seating [PhD thesis]. Technological University Dublin, 2011.
[43] Yang, S., & Lee, Y.-J. Viscoelastic characterization of polyurethane foam cushions under dynamic loading. Polymer Testing,2018.
[44] Dorugade, A., et al. Modeling and validation of static and dynamic seat cushion characteristics. In Proceedings of the 12th European LS-DYNA Conference.2019
[45] Fazekas, B., & Goda, P. A Comprehensive Method with Verification for Characterizing the Visco-Hyperelastic Material Model of Polyurethane Foam of Passenger Car Seats. Material. https://doi.org/10.3390/ma18153526103651, 2024
[46] H. M. Khanlo, A. Nouri, and S. M. Kamali, “Analyzing the effect of helicopter pilot cushion on body vibrations through numerical and analytical investigation,” J. Aerosp. Sci. Technol., vol. 17, no. 2, pp. 16–25, Summer 2024. doi: 10.22034/jast.2024.419274.1164.
[47] S. M. Kamali, A. Nouri, H. M. Khanlo, and H. Sabouri, “Investigating the Effect of Seat Suspension System and Cushion on the Dynamic Behavior of the 214 Helicopter Pilot's Body,” AUT J. Mech. Eng., vol. 9, no. 4, pp. 431–446, Oct. 2025, doi: 10.22060/ajme.2025.23838.6161.
[48] Singh, R., Davies, P., & Bajaj, A. K. Identification of Nonlinear and Viscoelastic Properties of Flexible Polyurethane Foam. Nonlinear Dynamics, 34(3–4), 319–340, 2003. doi: 10.1023/B:NODY.0000013511.07097.87.
مهندسی مکانیک مدرس
دوره 26، شماره 9
شهریور 1405
صفحه 743-755