مهندسی مکانیک مدرس

مهندسی مکانیک مدرس

توسعه مدل آیروالاستیک هواپیمای کامل برای بررسی اثر انعطاف‌پذیری بر ضرایب دینامیک پروازی آن

نوع مقاله : پژوهشی اصیل

نویسندگان
1 دانشکده مهندسی هوافضا، دانشگاه صنعتی شریف، تهران
2 دانشکده مهندسی هوافضا، دانشگاه صنعتی شریف، تهران، ایران
چکیده
هواپیماهای بدون سرنشین که اغلب سبک و انعطاف‌پذیرند از جمله وسایل پرنده پرکاربرد در سال‌های اخیر هستند که بسیار مورد توجه طراحان حوزه هوافضا قرار گرفته‌اند. نکته مهم در مورد طراحی این پرنده‌ها تاثیر متقابل تغییر شکل‌های سازه و بارهای آیرودینامیکی است یعنی انعطاف‌پذیر بودن پرنده سبب می‌شود حین اعمال بارهای آیرودینامیکی تغییر شکل‌هایی در پرنده ایجاد شود که سبب تغییر در ضرایب و مشتقات آیرودینامیکی آن خواهد شد. در پژوهش حاضر اثر انعطاف‌پذیری سازه بر مشتقات آیرودینامیکی استاتیکی و دینامیکی و به ویژه پایداری عرضی پرنده، مورد مطالعه قرار گرفته و مدلی برای محاسبه سریع این ضرایب معرفی شده است. این مدل براساس روش آیرودینامیک سریع و تیر الاستیک است و برای پرنده کامل و نامقید ارائه شده است. تحلیل سازه با روش مودال و با استفاده از شکل مودهای تیر (با روش اجزا محدود) و محاسبات آیرودینامیکی با روش پنل سه‌بعدی (ترکیب چمشه و دابلت) انجام شده و معادلات آیروالاستیک پرنده کامل به‌صورت همگیر و برحسب عملگرهای ماتریسی توسعه داده شده است. در انتها پس از صحت‌سنجی‌های انجام‌شده، برای یک هواپیمای بدون سرنشین، تاثیر انعطاف‌پذیری بر مشتقات در دو حالت مطالعه شده است. در یک حالت ضریب بار لیفت تغییر کرده و پس از تریم کردن پرنده، مشتقات مختلف محاسبه شده است. در حالت دیگر، با تغییر طول بال، مشتقات پرنده به ازای مقادیر مختلف نسبت منظری محاسبه شده است. نتایج نشان می‌دهد که انعطاف‌پذیری پرنده مورد مطالعه می‌تواند تا چند ده برابر حالت صلب، افزایش در برخی مشتقات عرضی پرنده ایجاد کند.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Developing an Aero-Elastic Model of a Full Aircraft to Study the Effect of Flexibility on its Flight Dynamics Derivatives

نویسندگان English

M. Borhanpanah 1
R. Dehghani Firouz-Abadi 2
1 Department of Aerospace Engineering, Sharif University of Technology, Tehran, Iran
2 Department of Aerospace Engineering, Sharif University of Technology, Tehran, Iran
چکیده English

Flexible and lightweight unmanned aerial vehicles (UAVs) have shown their widespread applications in recent years and hence attracted so much attention of various aerospace communities. Due to their high flexibility, the interactions of aerodynamic loading and structure deformations are the dominant factor in their design process. Aerodynamic causes a set of deformations in the structure which consequently alters aerodynamic coefficients. In the current study, the effect of UAV flexibility on aerodynamic derivatives and lateral stability of the vehicle was investigated and an efficient method is proposed to provide an accurate estimation of the aerodynamic coefficients. This method is based on fast aerodynamic calculations as well as the formulation of elastic beams and is given for a full free-free airplane. Vehicle analysis is conducted by using the Modal beam formulation (through finite element mode shapes) and aerodynamic calculations based upon the 3D panel method (source–doublet combination). The final aero-elastic coupled formulation the whole system is also given in terms of matrix operators. Verification studies are conducted for a special type of UAV and flexibility effects on derivatives are evaluated in the two states. In a first evaluation, the lift load factor is altered and after trimming the airplane, various aerodynamic derivatives are computed while in the second evaluation, with varying the wingspan length, the aerodynamic derivatives are obtained at each aspect ratio of the wing. Results show that flexibility can enhance some of the stability derivatives of the UAV up to several times.

کلیدواژه‌ها English

Aero-Elasticity
Stability
HALE UAV
Aerodynamic Derivatives
Flexible Airplane
Rodden WP. An aeroelastic parameter for estimation of the effects of flexibility on the lateral stability and control of aircraft. Journal of the Aeronautical Sciences. 1956;23(7):660-662. [Link] [DOI:10.2514/8.3630]
Buttrill Carey S, Bacon Barton J, Heeg J, Houck Jacob A, Wood David V. Aeroservoelastic simulation of an active flexible wing wind tunnel model. Technical Report. Langley: NASA; 1996. Report No: Unknown. [Link]
Patil MJ, Hodges DH, Cesnik CES. Nonlinear aeroelasticity and flight dynamics of high-altitude long-endurance aircraft. Journal of Aircraft. 2001;38(1):88-94. [Link] [DOI:10.2514/2.2738]
Patil MJ, Hodges DH, Cesnik CES. Nonlinear aeroelastic analysis of complete aircraft in subsonic flow. Journal of Aircraft. 2000;37(5):753-760. [Link] [DOI:10.2514/2.2685]
Patil MJ, Hodges DH, Cesnik CES. Limit cycle oscillations of a complete aircraft. 41st Structures, Structural Dynamics, and Materials Conference and Exhibit, 3-6 April 2000, Atlanta, GA, USA. Reston VA: AIAA; 2000. [Link] [DOI:10.2514/6.2000-1395]
Patil MJ, Hodges DH. Nonlinear aeroelasticity and flight dynamics of aircraft in subsonic flow. Proceedings of the 21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia. Reston VA: AIAA; 1998. [Link] [DOI:10.2514/6.1999-1470]
Pourtakdust H, Raoof N. Aeroelastic and flight dynamic analysis of a HALE aircraft. Journal of Aerosp Sciences Research. 2008;1(1):1-7. [Persian] [Link]
Farsadi T, Haddadpour H, Sina SA. Aeroelastic behavior of composite wings in compressible flow. Aerospace Knowledge and Technology Journal. 2013;1(2):24-32. [Persian] [Link]
Golparvar H, Irani S. An analytical & experimental investigation of effects of store on flutter speed for cropped delta wing/store model in low subsonic regime. Modares Mechanical Engineering. 2015;15(7):61-72. [Persian] [Link]
Pourshamsi H, Mazidi A, Fazelzadeh Haghighi SA. Flutter analysis of an aircraft wing carrying, elastically, an external store. Modares Mechanical Engineering. 2015;15(1):49-58. [Persian] [Link]
Moosazadeh H, Ghadiri Dehkordi B, Rasekh M. 2D curved plate non-linear vibration and aeroelastic analysis with in-plane and supersonic aerodynamic load in time domain. Modares Mechanical Engineering. 2015;14(15):405-413. [Persian] [Link]
Palacios R, Cesnik CES. Static nonlinear aeroelasticity of flexible slender wings in compressible flow. 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 18-21 April 2005, Austin, Texas. Reston VA: AIAA; 2005. [Link] [DOI:10.2514/6.2005-1945]
Fallah S, Ghadiri B, Heidarinejad G. Numerical study of aeroelastic instability behavior of Nasa 37 transonic compressor rotor blades. Modares Mechanical Engineering. 2017;17(3):123-134. [Link]
Carrión M, Steijl R, Woodgate M, Barakos GN, Munduate X, Gomez-Iradi S. Aeroelastic analysis of wind turbines using a tightly coupled CFD-CSD method. Journal of Fluids and Structures. 2014;50:392-415. [Link] [DOI:10.1016/j.jfluidstructs.2014.06.029]
Ghasemi AR, Tarighat MH. Aeroelastic analysis of composite wind turbines blades. Journal of Mechanical Engineering (Tabriz University). 2015;44(3):31-39 [Persian] [Link]
Meshkati Shahmirzadi A, Irani S, Farrokh M. Numerical analysis of blade flutter in low-pressure turbine. Modares Mechanical Engineering. 2016;16(5):187-198. [Persian] [Link]
Keshavarzi MM, Yousefi Koma A, Nejat A, Mohtasebi SS. Static aeroelastic simulation of a wing in transonic flow. Modares Mechanical Engineering. 2016;16(10):313-322. [Persian] [Link]
ZONA Technology [Internet]. Scottsdale: ZONA Technology, Inc.; 2018 [cited 2018 Dec 10]. Available from: https://www.zonatech.com/. [Link]
Yang C, Wang LB, Xie CC, Liu Y. Aeroelastic trim and flight loads analysis of flexible aircraft with large deformations. Science China Technological Sciences. 2012;55(10):2700-2711. [Link] [DOI:10.1007/s11431-012-4912-8]
Paul RC, Murua J, Gopalarathnam A. Unsteady and post-stall aerodynamic modeling for flight dynamics simulation. AIAA Atmospheric Flight Mechanics Conference, 13-17 January 2014, National Harbor, Maryland. Reston VA: AIAA; 2014. [Link] [DOI:10.2514/6.2014-0729]
Zhao YH, Hu HY. Aeroelastic analysis of a non-linear airfoil based on unsteady vortex lattice model. Journal of Sound and Vibration. 2004;276(3-5):491-510. [Link] [DOI:10.1016/j.jsv.2003.08.004]
Dutt HNV, Rajeswari SR. Wing-body interference using a hybrid panel method. Acta Mechanica. 1994;106(3-4):111-126. [Link] [DOI:10.1007/BF01213557]
Traugott JP, Patil MJ, Holzapfel F. Nonlinear dynamics and control of integrally actuated helicopter blades. 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 18-21 April 2005, Austin, Texas. Reston VA: AIAA; 2005. [Link] [DOI:10.2514/6.2005-2271]
Cho J, Chang Y. Supersonic flutter analysis of wings using an unsteady 3D panel method. Computers & Fluids. 2001;30(2):237-256. [Link] [DOI:10.1016/S0045-7930(00)00010-4]
Cho J, Han C, Cho L, Cho J. Steady/unsteady aerodynamic analysis of wings at subsonic, sonic and supersonic Mach numbers using a 3D panel method. International Journal for Numerical Methods in Fluids. 2003;42(10):1073-1086. [Link] [DOI:10.1002/fld.577]
Roohi Dehkordi I, Shahverdi H, Salehzadeh Nobari A, Khalili A. Numerical investigation of the aeroelastic instability of an aircraft wing, using finite element and unsteady panel methods. Aerospace Mechanics Journal. 2012;7(4):13-23. [Persian] [Link]
Katz J, Plotkin A. Low-speed aerodynamics: From wing theory to panel methods. New York: McGraw-Hill; 1991. [Link]
Shahverdi H, Salehzadeh Nobari A, Behbahani Nejad M, Haddadpour H. An efficient reduced-order modelling approach based on fluid eigenmodes and boundary element method. Journal of Fluids and Structures. 2007;23(1):143-153. [Link] [DOI:10.1016/j.jfluidstructs.2006.06.008]
Tuzcu İ. On the stability of flexible aircraft. Aerospace Science and Technology. 2008;12(5):376-384. [Link] [DOI:10.1016/j.ast.2007.09.003]
Vaz G. Modelling of sheet cavitation on hydrofoils and marine propellers using boundary element methods [Dissertation]. Lisbon: Aerospace Engineer of Instituto Superior T'ecnico; 2005. [Link]
Goland M. The flutter of a uniform cantilever wing. Journal of Applied Mechanics. 1945;12(4):A197-A208. [Link]
Haddadpour H, Firouz-Abadi RD. Evaluation of quasi-steady aerodynamic modeling for flutter prediction of aircraft wings in incompressible flow. Thin Walled Structures. 2006;44(9):931-936. [Link] [DOI:10.1016/j.tws.2006.08.020]