Practical formulas

Question 1

radius of gyration, k, formula

Answer 1

k^2 = I/A

I = second moment of area
A = cross sectional area

Question 2

euler buckling load, Pe, formula

Answer 2

Pe = n*(pi^2 * E * I/ L^2)

n = 1 for two free ends,
n = 2 for one free end and one fixed end,
n = 4 for two fixed ends

Question 3

second moment of area, I, formula

Answer 3

I = (b*d^3 / 12)

Question 4

cantilever deflection, delta, formula

Answer 4

delta = (W * L^3 / 3 * E * I)

W = load (N)
L = dist. between supporting and loading points (m)
E = young's modulus (N/m^2)
I = second moment of area (m^4)