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Aeroelasticity is the science which studies the interaction among inertial, elastic, and aerodynamic forces. It was defined by Collar in 1947 as "the study of the mutual interaction that takes place within the triangle of the inertial, elastic, and aerodynamic forces acting on structural members exposed to an airstream, and the influence of this study on design." In physics, an inertial frame of reference, or inertial frame for short (also descibed as absolute frame of reference), is a frame of reference in which the observers move without the influence of any accelerating or decelerating force. ...
There are separate articles about elasticity in economics, and about British rubber bands. ...
Aerodynamics is a branch of fluid dynamics concerned with the study of gas flows, first analysed by George Cayley in the 1800s. ...
Introduction
Modern airplane structures are not completely rigid, and aeroelastic phenomena arise when structural deformations induce changes on aerodynamic forces. The additional aerodynamic forces cause increasing of the structural deformations, which leads to greater aerodynamic forces. These interactions may become smaller until a condition of equilibrium is reached, or may diverge catastrophically. An Air France Boeing 777, a modern passenger jet. ...
The structure of a thing is how the parts of it relate to each other, how it is put together. This contrast with process, which is how the thing works; but process requires a viable structure. ...
Aerodynamics is a branch of fluid dynamics concerned with the study of gas flows, first analysed by George Cayley in the 1800s. ...
In physics, a force is anything that causes a free body with mass to accelerate. ...
Aeroelasticity can be divided in two fields of study: static and dynamic aeroelasticity. Look up static in Wiktionary, the free dictionary. ...
The word dynamics can refer to: a branch of mechanics; see dynamics (mechanics) the volume of music; see dynamics (music) When used referring to mechanics, it is referring to the study of the motion of both rigid bodies and particles. ...
Static aeroelasticity Static aeroelasticity studies the interaction between aerodynamic and elastic forces on an elastic structure. Mass properties are not significant in the calculations of this type of phenomena. Aerodynamics is a branch of fluid dynamics concerned with the study of gas flows, first analysed by George Cayley in the 1800s. ...
Mass is a property of a physical object that quantifies the amount of matter and energy it is equivalent to. ...
Divergence Divergence occurs when a lifting surface deflects under aerodynamic load so as to increase the applied load, or move the load so that the twisting effect on the structure is increased. The increased load deflects the structure further, which brings the structure to the limit loads (and to failure).
Control surface reversal -
Control surface reversal is the loss (or reversal) of the expected response of a control surface, due to structural deformation of the main lifting surface. Control reversal is an adverse affect on the controllability of aircraft. ...
Dynamic aeroelasticity Dynamic Aeroelasticity studies the interactions among aerodynamic, elastic, and inertial forces. Examples of dynamic aeroelastic phenomena are: Aerodynamics is a branch of fluid dynamics concerned with the study of gas flows, first analysed by George Cayley in the 1800s. ...
Inertia is the tendency of any state of affairs to persist in the absence of external influences. ...
Flutter Flutter is a self-starting vibration that occurs when a lifting surface bends under aerodynamic load. Once the load reduces, the deflection also reduces, restoring the original shape, which restores the original load and starts the cycle again. In extreme cases the elasticity of the structure means that when the load is reduced the structure springs back so far that it overshoots and causes a new aerodynamic load in the opposite direction to the original. Even changing the mass distribution of an aircraft or the stiffness of one component can induce flutter in an apparently unrelated aerodynamic component. Flutter: In electronics, rapid variation of signal parameters, such as amplitude, phase, and frequency. ...
Stiffness is the resistance of an elastic body to deflection by an applied force. ...
At its mildest this can appear as a "buzz" in the aircraft structure, but at its most violent it can develop uncontrollably with great speed and cause serious damage to or the destruction of the aircraft.
Flutter can also occur on structures other than aircraft. One famous example of flutter phenomena is the Tacoma Narrows Bridge. The Tacoma Narrows Bridge is a mile-long (1600 meter) suspension bridge with a main span of 2800 foot (850 m) (the third-largest in the world when it was first built) that carries Washington State Route 16 across the Tacoma Narrows of Puget Sound from Tacoma to Gig Harbor...
Dynamic response Dynamic response or forced response is the response of an aircraft to gusts and other external atmospheric disturbances.
Buffeting Buffeting is a high-frequency instability, caused by airflow disconnection from the airfoil or shock wave oscillations. It is a random forced vibration.
Other fields of study Other fields of physics may have an influence on aeroelastic phenomena. For example, in aerospace vehicles, stress induced by high temperatures is important. This leads to the study of aerothermoelasticity. Or, in other situations, the dynamics of the control system may affect aeroelastic phenomena. This is called aeroservoelasticity. Figure 1 Stress tensor In physics, stress is a measure of the internal distribution of force per unit area within a body that balances and reacts to the loads applied to it. ...
It has been suggested that this article or section be merged with Control theory. ...
Prediction and cure Aeroelasticity involves not just the external aerodynamic loads and the way they change but also the structural, damping and mass characteristics of the aircraft. Prediction involves making a mathematical model of the aircraft as a series of masses connected by springs and dampers which are tuned to represent the dynamic characteristics of the aircraft structure. The model also includes details of applied aerodynamic forces and how they vary. Damping is any effect, either deliberately engendered or inherent to a system, that tends to reduce the amplitude of oscillations of an oscillatory system. ...
A mathematical model is an abstract model that uses mathematical language to describe the behaviour of a system. ...
The model can be used to predict the flutter margin and, if necessary, test fixes to potential problems. Small carefully-chosen changes to mass distribution and local structural stiffness can be very effective in solving aeroelastic problems.
Media These videos detail the Active Aeroelastic Wing two-phase NASA--Air Force flight research program to investigate the potential of aerodynamically twisting flexible wings to improve maneuverability of high-performance aircraft at transonic and supersonic speeds, with traditional control surfaces such as ailerons and leading-edge flaps used to induce the twist. NASA logo Listen to this article · (info) This audio file was created from an article revision dated 2005-09-01, and does not reflect subsequent edits to the article. ...
The United States Air Force (or USAF) is the aerospace branch of the United States armed forces and one of the seven uniformed services. ...
It has been suggested that this article or section be merged with Sound barrier. ...
Aileron location on a Piper PA-28. ...
Image File history File links Active_Aeroelastic_Wing_time_lapse. ...
Image File history File links F-18A_Active_Aeroelastic_Wing_flight_test. ...
Related books - Bisplinghoff, R.L., Ashley, H. and Halfman, H., Aeroelasticity. Dover Science, 1996, ISBN 0486691896, 880 pgs;
- Dowell, E. H., A Modern Course on Aeroelasticity. ISBN 9028600574.
See also Aerospace engineering is the branch of engineering that concerns aircraft, spacecraft and related topics. ...
A mathematical model is the use of mathematical language to describe the behaviour of a system. ...
Oscillation is the periodic variation, typically in time, of some measure as seen, for example, in a swinging pendulum. ...
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