Plot an S-N (stress versus cycles-tofailure)
diagram with the alternating stress amplitude as the
ordinate against the common logarithm of the number of cycles
required for failure (see X3.21) as the abscissa. Plot all test data
and define the S-N diagram preferably using a regression
analysis or by drawing the best-fit smooth curve as closely as
possible through the points. The use of semilogarithmic paper
will facilitate the plotting. Indicate on the diagram specimens
that did not fracture by an arrow directed away from the plotted
point in the direction of increasing cycles.