Abstract
The ability of an aircraft wing or any aerodynamic surface to change its geometry or to “morph” during flight has interested aircraft designers over the years,
as morphing is almost always observed in nature and results in improved
efficiency and control in a wide range of ambient conditions. Morphing is
short for metamorphose; however, there is neither an exact definition nor an
agreement among the researchers about the type or the extent of the geometrical changes necessary to qualify an aircraft for the title “wing morphing.” In general, the geometrical parameters of an aircraft that can be affected
by morphing solutions can be categorized into three main areas: planform
morphing (span, sweep, and chord), out-of-plane morphing (twist, dihedral/
gull, and spanwise bending), and airfoil morphing (camber and thickness).
Historically, morphing in man-made aircraft almost always leads to penalties
in terms of cost, complexity, and weight, although in certain circumstances
these were overcome by system level benefits. The current trend for highly
efficient and “green” aircraft makes such compromises less acceptable, calling
for innovative and practical morphing designs able to provide more benefits
and fewer drawbacks. Recent developments in “smart” materials have been
shown to overcome some limitations and enhance the benefits from existing
design solutions. The reader is referred to a comprehensive review paper on
morphing aircraft by Barbarino et al. (2011) for more background information.
As an example of “wing morphing,” this chapter will focus on the topic of
camber morphing of an airfoil using smart material actuators. In aerodynamics, camber represents the effective curvature of an airfoil. The term camber
morphing simply refers to the change of the curvature of the airfoil by means
of actuators, in our case, by the means of smart materials.