Editing Aeroelasticity (section)

{{Short description|Interactions among inertial, elastic, and aerodynamic forces}}
[[File:Nasa electra testing.jpg|thumb|NASA testing a scale model [[Lockheed L-188 Electra|Lockheed Electra]] in a wind tunnel for flutter]]

'''Aeroelasticity''' is the branch of [[physics]] and [[engineering]] studying the interactions between the [[inertial force|inertial]], [[elasticity (physics)|elastic]], and [[aerodynamic force|aerodynamic]] forces occurring while an elastic body is exposed to a [[fluid]] flow. The study of aeroelasticity may be broadly classified into two fields: ''static aeroelasticity'' dealing with the static or [[steady state]] response of an elastic body to a fluid flow, and ''dynamic aeroelasticity'' dealing with the body's [[Dynamics (mechanics)|dynamic]] (typically [[vibration]]al) response.

Aircraft are prone to aeroelastic effects because they need to be lightweight while enduring large aerodynamic loads.  Aircraft are designed to avoid the following aeroelastic problems:
# '''divergence''' where the aerodynamic forces increase the twist of a wing which further increases forces; 
# '''control reversal''' where control activation produces an opposite aerodynamic moment that reduces, or in extreme cases reverses, the control effectiveness; and 
# '''flutter''' which is uncontained vibration that can lead to the destruction of an aircraft.

Aeroelasticity problems can be prevented by adjusting the mass, stiffness or aerodynamics of structures which can be determined and verified through the use of calculations, ''ground vibration tests'' and ''flight flutter trials''. Flutter of [[Flight control surfaces|control surfaces]] is usually eliminated by the careful placement of ''mass balances''.

The synthesis of aeroelasticity with [[thermodynamics]] is known as ''aerothermoelasticity'', and its synthesis with [[control theory]] is known as ''aeroservoelasticity''.