Chapter 9
Design Study of Morphing Wing with MFC Actuators
M. M. Mennu, B. Tran, C. S. Tripp, and P. G. Ifju
Abstract A micro-aerial vehicle (MAV) has been developed to achieve high versatility through biological inspiration from
bird’s wings. One way of achieving optimized flight performance during different flight regimes is by incorporating a
sweeping mechanism in the vehicle. Sweeping mechanisms allow a change in the aspect ratio of the wing as well as the overall
span of the wing. The main challenge involves creating the mechanism to control the outboard section of the wing for a robust
sweeping authority. A tendon-actuator mechanism with an elastic spring recovery system has been developed for this cause.
In addition, macro-fiber composites (MFCs) were used as the control effectors for this vehicle both as ailerons and elevator.
The placement of the MFCs was optimized for the required aileron effectiveness and overall aircraft performance. The
analytical models were compared with the experimental results obtained through DIC, a full-field deformation measurement
technique, for the entire wing.
9.1 Introduction
Morphing concepts have been widely applied to unmanned aerial vehicles (UAVs) as well as micro aerial vehicles (MAVs).
The fact that these vehicles are smaller in size and do not need an onboard pilot, which would require additional certifications,
makes them a viable option for adopting morphing mechanisms [1]. These vehicles are flown at slower speeds with lower
aerodynamic loading which allows for morphing designs without overly complex geometries and weight penalties. In
addition, there is a greater demand on the market now for more efficient and maneuverable vehicles especially for military
applications with more advanced missions and a wider flight envelope. An actuation system that has been recently developed
is the macro-fiber composite (MFC). MFCs were first developed by Wilkie and his team at NASA Langley Research Center
[2]. MFCs are made of lead zirconate titanate (PZT) fibers which exhibit piezoelectric properties. The piezoelectric property
describes the ability of a material to deform when there is accumulation of electric charge due to a voltage potential. PZT fibers
were embedded in epoxy layer and then sandwiched between two interdigitated electrode patterns to create an MFC structure.
In the past, MFCs have been incorporated on various parts of a morphing vehicle as control actuators, variable camber control,
etc.. . . The main advantage to using MFCs is their ability to be placed directly on the surface of the vehicle without any
significant penalty in weight or form drag. However, MFCs produce small strains which requires a significant consideration
on the placement and location of these actuators on the vehicle.
9.2 Background
Before exploring the designs of MAVs both computationally and experimentally, it is important to study and characterize the
material properties of the composite material to be used so it can be accurately modeled in the finite element solver. There are
mainly two types of composites that will be used for this research. Unidirectional carbon fiber (H40/321) is one type where all
the fibers are aligned along one direction. This gives the unidirectional carbon fiber excellent strength in the longitudinal
direction but poor strength in the lateral direction on the order of the strength of the matrix material. The other type of
composite used is bidirectional carbon fiber (AS4 plain weave) which has fibers aligned both in the longitudinal and lateral
directions and woven into a cloth giving it superior strength in both directions. However, bidirectional carbon fiber has weaker
M. M. Mennu (*) · B. Tran · C. S. Tripp · P. G. Ifju
Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA
e-mail: mmennu@ufl.edu; tranb@ufl.edu; chadtripp@ufl.edu; ifju@ufl.edu
© The Society for Experimental Mechanics, Inc. 2021
R. P. Singh, V. Chalivendra (eds.), Mechanics of Composite, Hybrid and Multifunctional Materials, Volume 6,
Conference Proceedings of the Society for Experimental Mechanics Series, https://doi.org/10.1007/978-3-030-59868-6_9
61
Design Study of Morphing Wing with MFC Actuators
M. M. Mennu, B. Tran, C. S. Tripp, and P. G. Ifju
Abstract A micro-aerial vehicle (MAV) has been developed to achieve high versatility through biological inspiration from
bird’s wings. One way of achieving optimized flight performance during different flight regimes is by incorporating a
sweeping mechanism in the vehicle. Sweeping mechanisms allow a change in the aspect ratio of the wing as well as the overall
span of the wing. The main challenge involves creating the mechanism to control the outboard section of the wing for a robust
sweeping authority. A tendon-actuator mechanism with an elastic spring recovery system has been developed for this cause.
In addition, macro-fiber composites (MFCs) were used as the control effectors for this vehicle both as ailerons and elevator.
The placement of the MFCs was optimized for the required aileron effectiveness and overall aircraft performance. The
analytical models were compared with the experimental results obtained through DIC, a full-field deformation measurement
technique, for the entire wing.
9.1 Introduction
Morphing concepts have been widely applied to unmanned aerial vehicles (UAVs) as well as micro aerial vehicles (MAVs).
The fact that these vehicles are smaller in size and do not need an onboard pilot, which would require additional certifications,
makes them a viable option for adopting morphing mechanisms [1]. These vehicles are flown at slower speeds with lower
aerodynamic loading which allows for morphing designs without overly complex geometries and weight penalties. In
addition, there is a greater demand on the market now for more efficient and maneuverable vehicles especially for military
applications with more advanced missions and a wider flight envelope. An actuation system that has been recently developed
is the macro-fiber composite (MFC). MFCs were first developed by Wilkie and his team at NASA Langley Research Center
[2]. MFCs are made of lead zirconate titanate (PZT) fibers which exhibit piezoelectric properties. The piezoelectric property
describes the ability of a material to deform when there is accumulation of electric charge due to a voltage potential. PZT fibers
were embedded in epoxy layer and then sandwiched between two interdigitated electrode patterns to create an MFC structure.
In the past, MFCs have been incorporated on various parts of a morphing vehicle as control actuators, variable camber control,
etc.. . . The main advantage to using MFCs is their ability to be placed directly on the surface of the vehicle without any
significant penalty in weight or form drag. However, MFCs produce small strains which requires a significant consideration
on the placement and location of these actuators on the vehicle.
9.2 Background
Before exploring the designs of MAVs both computationally and experimentally, it is important to study and characterize the
material properties of the composite material to be used so it can be accurately modeled in the finite element solver. There are
mainly two types of composites that will be used for this research. Unidirectional carbon fiber (H40/321) is one type where all
the fibers are aligned along one direction. This gives the unidirectional carbon fiber excellent strength in the longitudinal
direction but poor strength in the lateral direction on the order of the strength of the matrix material. The other type of
composite used is bidirectional carbon fiber (AS4 plain weave) which has fibers aligned both in the longitudinal and lateral
directions and woven into a cloth giving it superior strength in both directions. However, bidirectional carbon fiber has weaker
M. M. Mennu (*) · B. Tran · C. S. Tripp · P. G. Ifju
Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA
e-mail: mmennu@ufl.edu; tranb@ufl.edu; chadtripp@ufl.edu; ifju@ufl.edu
© The Society for Experimental Mechanics, Inc. 2021
R. P. Singh, V. Chalivendra (eds.), Mechanics of Composite, Hybrid and Multifunctional Materials, Volume 6,
Conference Proceedings of the Society for Experimental Mechanics Series, https://doi.org/10.1007/978-3-030-59868-6_9
61