b.
Using the principle of parallel axes, answer the questions below to perform a manual calculation to show that the second moment of area about the horizontal axis through the centre of area for the asymmetric hollow section is 194 x 103 mm4 (to 3 sig. fig.). Show all your workings.
i. Show that the second moment of area of the box section about the centre of area of the asymmetric hollow section in Figure 4 is 136 x 103 mm4 (to 3 sig. fig.).
ii. Show that the second moment of area of the side flange about the centre of area of the asymmetric hollow section in Figure 4 is approximately 58.2 x 103 mm4 (to 3 sig. fig.).
iii. Show that the second moment of area of the complete asymmetric hollow section in Figure 4 about its centre of area is approximately 194 x 103 mm4 (to 3 sig. fig.).
c.
Use the engineers’ theory of bending to calculate the maximum bending stress in the asymmetric hollow section shown in Figure 4 if it is subjected to a bending moment of 1750 N m about a horizontal axis through the centre of area.
