For each section illustrated, find the second moment of area, the location of neutral axis, and the
distances from the neutral axis to the top and bottom surfaces. Consider that the section is
transmitting a positive bending moment about the z axis, Mz, where Mz = 10 kip.in if the dimensions
of sections are given in Imperial unites, or Mz = 1.13kN.m in the dimensions are SI unites.
Determine the resulting stresses at the top and bottom surfaces and at every abrupt change in the
cross section.
a)
b)
3
A 
10 10  0.858
0.448
4
 1.915  10
3
B 
10 10  0.358
0.448
3
psi (Tensile)
 7.991  10
psi (Tensile)
 379.464
psi (Compressive)
3
C 
10 10  0.017
0.448
3
D 
10 10  1.017
0.448
4
 2.27  10
psi (Compressive)
4
3
2
1
𝑚𝑚
I1= 4.29 (106) mm4
6
1 
1.13 10  57.29
6
 15.09
4.29 10
MPa (Tensile)
6
2 
1.13 10  44.79
6
 11.798 MPa (Tensile)
4.29 10
6
3 
1.13 10  30.21
6
 7.957 MPa (Compressive)
4.29 10
6
4 
1.13 10  42.71
6
4.29 10
 11.25
MPa (Compressive)