SIDDARTHA INSTITUTE OF

SCIENCE AND TECHNOLOGYPowerPoint presentation

on

Aero ElasticityBy

SANJANA P U

CONTENTSAEROELASTICITY &

COLLARS TRIANGLE

NECESSITY

HISTORY

CLASSIFICATIONS

PRECAUTIONS

FURTHER DEVELOPMENTS

INTRODUCTION Aereolasticity is the study of the interaction of

inertial, structural and aerodynamic forces on aircraft, buildings, surface vehicles etc.

FIGURE : COLLARS TRIANGLE

NECESSITY:STUDY OF

CATASTROPHIC EFFECTS

STUDY OF AERODYNAMIS IN ROTOR DESIGN

WIND MILLS & WIND GENERATORS] 

WIND ENERGY INDUSTRY

A BIT OF HISTORY: Control surface flutter became a frequent phenomenon during World War-I.

It was solved by placing a mass balance around the control surface hinge line

HISTORIC EXAMPLES:• Handley Page O/400 (elevators-

fuselage)• Junkers JU90 (fluttered during flight

flutter test)• P80, F100, F14 (transonic aileron buzz)• T46A (servo tab flutter)• F16, F18 (external stores LCO,

buffeting)• F111 (external stores LCO)• F117, E-6 (vertical fin flutter)

AERO ELASTICITY

STATIC AEROELASTICITY

DIVERGENCE

CONTROL

REVERSAL

DYNAMIC AEROELASTICITY

FLUTTE

R

BUFFETING

TRANSONIC

STATIC DYNAMIC

Deals with the static or steady response of an elastic body to a fluid flow.

Effects:

 Divergence Control reversal 

Deals with the body’s dynamic  response.

Effects:

Flutter Buffetting Transonic Aero

elasticity

AERO ELASTICITY

Divergence is a phenomenon in which the

elastic twist of the wing suddenly becomes

theoretically infinite, typically causing the

wing to fail spectacularly.

Control reversal is a phenomenon occurring

only in wings with ailerons or other control

surfaces, in which these control surfaces

reverse their usual functionality

DIVERGENCE:

CONTROL REVERSAL:

STATIC AEROELASTICITY

FLUTTER:Dynamic instability of an elastic structure in

a fluid flow. Cause: positive feedback between the body's

deflection and the force exerted by the fluid flow.

DYNAMIC AEROELASTICITY

BUFFETING: A high-frequency instability, caused by

airflow separation or shock wave oscillations from one object striking another.

BUFFETING:CAUSE: Sudden impulse of load increasing.

EFFECT: Generally it affects the tail unit of the aircraft structure due to air flow downstream of the wing.

TRANSONIC AERO ELASTICITY:A phenenenon that impacts stability of aircraft

known as 'transonic dip', in which the flutter speed can get close to flight speed

PRECAUTIONS:Aeroelastic Design (Divergence, Flutter, Control Reversal)Wind tunnel testing (Aeroelastic scaling)Ground Vibration Testing (Complete modal analysis of aircraft structure)Flight Flutter Testing (Demonstrate that flight envelope is flutter free)

FUTURE OF AEROELASTICITYAeroelasticity is a very vibrant research

topic.Several improvements to aeroelastic design

processes being developed are:–Very large, fully coupled CFD/CSD aeroelastic models–Aeroelastic tailoring–Active aeroelastic structures

QUERIE

S

THANK YOU