1.A 5160H steel was tested in fatigue and the distribution of cycles to failure at constant stress level was found to be n = W[36 . 9,133 . 6, 2 . 66] in 103 cycles. Plot the PDF of n and the PDF of...

1.A 5160H steel was tested in fatigue and the distribution of cycles to failure at constant stress level was found to be n = W[36.9,133.6, 2.66] in 103 cycles. Plot the PDF of
n
and the PDF of the lognormal distribution having the same mean and standard deviation. What is the L10 life (see Prob. 20–19) predicted by both distributions? 2. A material was tested at steady fully reversed loading to determine the number of cycles to failure using 100 specimens. The results were

where
L
is the life in cycles and
f
is the number in each class. Assuming a lognormal distribution,

plot the theoretical PDF and the histographic PDF for comparison.