Tiltrotor aircraft are equipped with large rotors, usually driven by heavy engines in nacelles located at the tip of the wings. This combination of large rotors and high masses on wings which form a relatively elastic support makes whirl flutter a critical phenomenon for the design of the aircraft and its performance. In this article, a multibody-based simulation model of a tiltrotor wind tunnel model is presented, combining a mixed finite element/multibody representation of the support, a detailed kinematic model of the rotor hub and a strip-wise definition of air loads on the blades. Investigations on the effect of parameter changes and non-linearities on the calculation of the aeroelastic stability boundary are executed. The selected operational points are taken from wind tunnel experiments performed by a consortium of partners in the course of the European ADYN project. The regarded wind tunnel model is a half model of a tiltrotor wing, simplified for the use in whirl flutter investigations. The rotor is four-bladed; the rotor hub is of a gimbal type. Structural dynamics properties of the model are known from detailed experimental investigations. Numerical analyses of the dynamic behaviour of the model are performed in the frequency and in the time domain. Results show considerable differences for linear and non-linear models. This paper describes the simulation approach, the model setup and the comparison of the data with selected experimental results.
Bianchi E, Russo A, Kießling F, et al. Numerical whirl-flutter investigation of the European tiltrotor concept: current status and future prospects. In: European rotorcraft forum, Marseilles, France, 14–16 September 2004.
3.
Saporiti A. TILTAERO – Tiltrotor interactional aerodynamics. In: Presentation D34. Aeronautics days, Vienna, Austria, 19–21 June 2006.
4.
Stabellini A. The European tilt rotor-status of ERICA design and test activities. In: Presentation 5E2. Aeronautics days, Madrid, Spain, 30 March–1 April 2011.
5.
Reed WH, III. Review of propeller-rotor whirl flutter. NASA Technical Report TR R-264, Langley Research Center, Langley Station, VA, 1967.
6.
Kießling F. Zur Problematik von Whirl-Flatteruntersuchungen von V/STOL-Flugzeugen. Forschungsbericht 74-11, Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt, Institut für Aeroelastik, Göttingen, Germany, 1974.
7.
Serling RS. The Electra story: aviation’s greatest mystery. New York: Doubleday/Bantam, 1963/1991.
8.
Cecrdle J. Whirl flutter analysis of the small transport aircraft. In: Proceedings of international forum on aeroelasticity and structural dynamics (IFASD), Stockholm, Sweden, 2007.
9.
Donham RE and Osterholt DJ. Utilizing test results to show adding flexibility of propeller blades is more representative than the classical rigid blade propeller whirl flutter analysis. In: Proceedings of international forum on aeroelasticity and structural dynamics (IFASD), Stockholm, Sweden, 2007.
10.
Reed WH III and Bland SR. An analytical treatment of aircraft propeller precession instability. NASA technical note D-659, 1961.
11.
Nixon MW, Langston CW, Singleton JD, et al. Aeroelastic stability of a four-bladed semi-articulated soft-inplane tiltrotor model. In: American helicopter society 59th annual forum, Phoenix, AZ, 6–8 May, 2003.
12.
MasaratiPPiatakDJQuarantaG. Soft-inplane tiltrotor aeromechanics investigation using two comprehensive multibody solvers. J Am Helicopter Soc2008; 53: 179–192.
13.
MattaboniMMasaratiPMantegazzaP. Multibody simulation of a generalized predictive controller for tiltrotor active aeroelastic control. Proc. I MechE, Part G: J Aerospace Engineering2012; 226: 197–216.
14.
Hodges DH. A new approach to aeroelastic response, stability and loads of missiles and projectiles. Final report, U.S. army research office grant 40448-EG. school of aerospace engineering, Georgia Institute of Technology, Atlanta, GA, USA, 2004.
15.
KrügerWRKlimmekTLiepeltR. Design and aeroelastic assessment of a forward-swept wing aircraft. CEAS Aeronautical J2014; 5: 419–433.
16.
Acree CW Jr, Peyran RJ and Johnson W. Rotor design for whirl flutter: an examination of options for improving tiltrotor aeroelastic stability margins. Proceedings of American Helicopter Society 55th Annual Forum, Montréal, Quebec, Canada, 25–27 May 1999.
17.
Yang C and Xia P. Aeroelastic stability of wing/pylon/rotor coupled system for tiltrotor aircraft in forward flight. Science China technological sciences. Berlin/Heidelberg: Science China Press/Springer, 2011, pp.2708–2715.
18.
KimTShinSKimT. Analysis of tiltrotor whirl flutter in time and frequency domain. J Mech Sci Technol2009; 23: 3281–3291.
ArnoldJEinarssonGKrügerWR. Multibody simulation of an oscillating aeroelastic wing model. NAFEMS Int J CFD Case Stud2009; 8: 5–18.
22.
KrügerWR. A multibody approach for modelling of the manoeuvring aeroelastic aircraft during preliminary design. J Aerospace Eng2008; 222: S887– S894.
23.
Krüger WR and Spieck M. Multibody simulation of low frequency aeroelastic wing loads. In: Functional and mechanical integration of weapons with land and air vehicles, RTO-MP-108, NATO Research and Technology Organisation, 2005.
24.
Krüger WR. Multibody dynamics for the coupling of aeroelasticity and flight mechanics of highly flexible structures. In: Proceedings of international forum on aeroelasticity and structural dynamics (IFASD), Stockholm, Sweden, 2007.
25.
Rezaeian A. Whirl flutter analysis of a wind tunnel model using multidisciplinary simulation and multibody dynamics. In: Proceedings of 37th European rotorcraft forum, Vergiate/Gallarate, Italy, 13–15 September 2011.
26.
Bottasso CL, Trainelli L, Abdel-Nour P, et al. Tilt-rotor analysis and design using finite element multibody procedures. In: 28th European rotorcraft forum, Bristol, UK, 17–20 September 2002.
27.
Masarati P, Quaranta G, Lanz M, et al. Dynamic characterization and stability of a large size multibody tiltrotor model by POD analysis. In: ASME 19th VIB, Chicago, IL, USA, 2–6 September 2003.
28.
MasaratiPMorandiniM. An ideal homokinetic joint formulation for general-purpose multibody real-time simulation. Multibody Syst Dyn2008; 20: 251–270.
29.
MasaratiP. Direct eigenanalysis of constrained system dynamics. Proc IMechE, Part K: J Multi-body Dynamics2009; 223: 335–342. DOI: 10.1243/14644193JMBD211.
30.
Masarati P, Morandini M, Quaranta G, et al. Open-source multibody analysis software. In: Multibody dynamics 2003, international conference on advances in computational multibody dynamics, Lisboa, Portugal, 1–4 July 2003.
31.
Arnold M and Vaculin O (eds). Multibody system simulation in vehicle system dynamics. To the memory of Willi Kortüm (1938–2002) [Special issue]. Vehicle Syst Dyn 2004; 41: 335–429.
Surrey S, Wendisch J-H and Wienke F. Coupled fluid-structure simulations of a trimmed helicopter rotor in forward flight. In: 19. DGLR-Fachsymposium der STAB, München, Germany, 4–5 November 2014.
35.
WallrappO. Standardization of flexible body modeling in multibody system codes, part I: definition of standard input data. Mech Struc Mach1994; 22: 283–304.
36.
Arnold J. Using multibody dynamics for the simulation of flexible rotor blades – getting the mechanical coupling right? In: Proceedings of European rotorcraft forum, Hamburg, Germany, 2009.
37.
Rezaeian A. Stability analysis of time-periodic systems using multibody simulation for application to helicopters. In: Proceedings of Deutscher Luft- und Raumfahrtkongress, Aachen, 2009.
38.
Eich-SöellnerEFührerC. Numerical methods in multibody dynamics, Teubner: Stuttgart, 1998.
39.
Krüger WR. Multibody analysis of whirl flutter dynamics on a tiltrotor wind tunnel model. In: Proceedings of international forum of aeroelasticity and structural dynamics (IFASD), Seattle, WA, 2009.
