2nd Moments of Area

Question 1

Rectangular cross section

Answer 1

Ixx = bd^3/12

Iyy = db^3/12

b=width
d = height

Question 2

I section

Answer 2

Ixx = (bd^3/12) - [(b-tw)*dw^3/12]

Iyy = (2tfb^3/12) + dw*tw^3/12

b=width;
d=height;
tw=inner width;
dw=inner height;
tf=flange height

Question 3

circular cross section

Answer 3

-double symmetry so Ixx = Iyy

Ixx = pi*d^4/64 = Iyy

d = radius

Question 4

what is the stress distribution given by

Answer 4

sigma z = Bending moment(a)/ 2nd moment of area I(aa)