00:01
To calculate principle stresses, we do sigma x plus sigma y over 2, plus or minus a square root, a sigma x minus sigma y over 2 squared minus tau xy squared.
00:20
It's going to be 82 and 45 over 2, that's going to be 63 .5, and then that's going to be 82, minus 45, is 32 divided by 7 sorry 37 divided by 2 and we square that that's going to be 142 .5 tau is just 20 it's going to be 400 i'm sorry this is plus so we get 63 .5 plus or minus 27 .26 which means that the principal stresses are 90 .76 megapascals and 36 .24 megapascals.
01:12
Now that's for the left figure, for the right figure.
01:18
Xy, sorry, tau xy is zero.
01:22
So the principal tresses are 82 megapascals for both for the right figure.
01:39
Now using the tresca criteria we get for the left figure tau max is 90 .76, which is sigma 1, minus sigma 2, 36 .24 divided by 2.
02:02
That's going to be 27 .26 megapascals, the factor of safety...