This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: AAE 352 1 AAE352 Lecture 29 Structural stability – Part 2 Stability of mechanisms and wings The ability of a flexible system to maintain a definite equilibrium form (or state) under a given loading condition AAE 352 2 Column buckling analysis with a side force and a compressive force is different because θ is never zero F k k/PL >1 k/PL <1 θ AAE 352 3 Solve for the deflection θ P P θ L F F AAE 352 4 Solve for the deflection θ Flexibility depends on the axial force P P θ F ( 29 PL k FL PL k FL k PL FL M k L P FL M pin pin = = = + 2245 • + = = ∑ ∑ θ θ θ θ θ θ sin PL k 1 ) FL ( = ∂ ∂ θ AAE 352 5 Flexibility & stiffness definitions The inverse of flexibility is stiffness = flexibility PL k 1 ) FL ( = ∂ ∂ θ PL k ) FL ( / 1 = ∂ ∂ θ = stiffness AAE 352 6 Flexibility and stiffness • A rigid structure has zero flexibility – it will not deform • A rigid structure has infinite stiffness • Zero stiffness means that the structure will not resist an increased external load • Infinite flexibility means that a structure cannot resist an increased load PL k 1 ) FL ( = ∂ ∂ θ PL k ) FL ( / 1 = ∂ ∂ θ AAE 352...
View
Full
Document
This note was uploaded on 01/18/2012 for the course AAE 352 taught by Professor Chen during the Fall '08 term at Purdue.
 Fall '08
 Chen

Click to edit the document details