1. AAE 556 Aeroelasticity Lecture 14
Aeroelastic tailoring
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2. Aeroelastic tailoring benefits
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3. Apparatus-stiffness tailoring model
view B-B (looking upstream, chordwise)
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4. Stiffness tailoring model
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5. Purdue Aeroelasticity
Flexural axis
Definition - a line (locus of points) along which the wing structure stream-wise angle of attack is zero when a discrete load is applied there – with the “wind” off. L b yo xo
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6. Structural angular displacements due to upward load P at –xo,yo
Solve for the flexural axis coordinates by setting the chordwise elastic angle of attack to zero
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7. Flexural axis with cross-coupling stiffnesses
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8. Plug expressions for stiffness terms to get the flexural axis position
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9. Purdue Aeroelasticity
example
Wash-out laminate
Increase divergence
Wash-in laminate
Increase lift
forward b
When wing is sweptforward increase divergence speed by moving the b axis forward (plus)
aft/back
aft/back g
forward
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10. Purdue Aeroelasticity
Divergence
Get rid of divergence
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11. Purdue Aeroelasticity
Example (page 171)
Wash-out laminate
Increase divergence
Wash-in laminate
Increase lift
Wash-out laminate
Increase divergence
Wash-in laminate
Increase lift g
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12. Purdue Aeroelasticity
Critical wing sweep angle vs. structural angle g Wings with sweep angles above the curves shown will not diverge.
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