Morphing Airfoil with Thermally Activated SMA Actuators

In this paper we study a type of design of Shape Memory Alloy (SMA) wire actuated morphing airfoil having discontinuous skin by targeting trailing edge deflection and changing camber. The design aims at airfoils to have optimal directional stiffness and relaxed shear constraint to allow the required change to create a conformal target shape. The trailing edge deflection of the morphing airfoil structure is produced by the electrical actuation via Joule heating of the actuators placed in the airfoil in various different configurations. Actuation response is tested under quasi-static loading and partial loading–unloading cycles applied to the actuators. Deformation characteristics are analyzed for these actuation schemes. Response time for various actuation rates and also the functional fatigue of SMA actuators due to variable stiffness conditions are investigated. Aerodynamic characteristics of this design are analyzed under a simulated free-stream flow velocity of up to 20 m/s and up to aerodynamic stall. For a maximum trailing edge rotation of 9°, a 150% increase in the coefficient of lift is observed. These results are further compared with wind tunnel test results which show promising outcome. Various aspects of aerodynamic performance enhancement and possibilities to realize it with distributed dynamic control via morphing structures are discussed.

[1]  T. Nam,et al.  Effect of incomplete thermal cycling on the transformation behaviour of NiTi , 2006 .

[2]  Vidyashankar R. Buravalla,et al.  Differential and integrated form consistency in 1-D phenomenological models for shape memory alloy constitutive behavior , 2007 .

[3]  Christopher A. Martin,et al.  Overview of the ARPA/WL Smart Structures and Materials Development-Smart Wing contract , 1996, Smart Structures.

[4]  A. Khandelwal,et al.  Evolution kinetics in Shape Memory Alloys under arbitrary loading: Experiments and modeling , 2011 .

[5]  Jayanth N. Kudva,et al.  Development of Next Generation Morphing Aircraft Structures , 2007 .

[6]  T. Nam,et al.  Partial thermal cycling of NiTi , 2008 .

[7]  C. M. Wayman,et al.  Shape-Memory Materials , 2018 .

[8]  D. Roy Mahapatra,et al.  Dynamics and control of buckling type devices using SMA wire integrated beam , 2008, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[9]  L. Brinson.  One-Dimensional Constitutive Behavior of Shape Memory Alloys: Thermomechanical Derivation with Non-Constant Material Functions and Redefined Martensite Internal Variable , 1993 .

[10]  Ron Barrett,et al.  Post-buckled precompressed elements: a new class of control actuators for morphing wing UAVs , 2007 .

[11]  V. Jha,et al.  Constitutive modeling of shape memory alloy wire with non-local rate kinetics , 2009 .

[12]  Shaker A. Meguid,et al.  Shape morphing of aircraft wing: Status and challenges , 2010 .

[13]  Vidyashankar R. Buravalla,et al.  A Correction to the Brinson's Evolution Kinetics for Shape Memory Alloys , 2008 .

[14]  Tim Smith,et al.  Morphing Inflatable Wing Development for Compact Package Unmanned Aerial Vehicles , 2004 .

[15]  Tomohiro Yokozeki,et al.  Mechanical properties of corrugated composites for candidate materials of flexible wing structures , 2006 .

[16]  John Yen,et al.  Design and Implementation of a Shape Memory Alloy Actuated Reconfigurable Airfoil , 2003 .

[17]  Liang Jun,et al.  A changeable aerofoil actuated by shape memory alloy springs , 2008 .