00:03
So given the composite beam, we need to transform the materials of the beam into a uniform material design.
00:09
So n is e of steel over e of aluminum.
00:16
So that is 200 over 70.
00:20
And so that equals 2 .857143.
00:25
So the equivalent width of the steel component will be equal to b -s -t -e -q is equal to n -b -s -t.
00:33
So that'd be 2 .857143 times 30.
00:39
Instead, i'll give you 85 .7143 millimeters.
00:50
So for the neutral axis, we need to get the centered of the equivalent cross -section in order to get the location of the neutral axis.
01:05
So y is equal to, so substituting, we get 50 times, 30 times 20 plus 20 times 40 times 85 .7143, all divided by 30 times 20 plus 40 times 85 .7143.
01:35
To where y then equals 24 .468 millimeters...