Buckling

Question 1

What is Buckling?

Answer 1

Critical axial compressive load.
Instability due to material or geometric imperfections caused by load.

Question 2

Buckling Assumptions

Answer 2

• Assume columns are slender
• Subject to compressive load
• Used in aircraft

Question 3

What is the Pcr?

Answer 3

Critical Load of a beam.
Where neutral equilibrium is observed.

Question 4

Pcr of a column

Answer 4

(π²n²E*I)/le²

where:
n = Inflection points
le = Length

Question 5

Effective Length Conditions

Answer 5

Pin-Pin: Le = L
Fixed-Fixed: Le = 0.5L
Fixed-Free: Le = 2L
Fixed-Pin: Le = 0.7L

Question 6

What is an eccentric load?

Answer 6

Load not applied to the ends of the columns or when the column is not completely straight.

Question 7

Eccentricity effect on Pcr

Answer 7

Beam starts fails before Pcr when eccentrically loaded.

Question 8

Critical Stress of a beam

Answer 8

Pcr/A = π²E/(le/r)²

Question 9

Gyration Radius of a beam

Answer 9

r = √(I/A)

Question 10

Slenderness Ratio of a beam

Answer 10

Le/r = Le/√(I/A)

Question 11

What is the factor of safety?

Answer 11

σ(working) = σmax/n

where:
n = Safety Factor