$$\Delta\sigma_C$$
DNV C203 S-N curves
This document shows how to obtain the DNV C203 S-N curves (see DNV-RP-C203 (2016)) from the category as given in the Preferences in Ashes.
Note: the category as defined in the Eurocode is a number that corresponds to the stress that gives 100% damage at two million cycles. This value is called reference stress and is noted
The separation between the two regions is defined as
$$N=1\cdot10^7$$
in air and $$N=1\cdot10^6$$
in water.For region
$$i$$
, the equation for the S-N curve is given by $$S=N^{m_i}\cdot a_i$$
, where $$m_1, m_2, a_1$$
and $$a_2$$
are given in tables 2-1 and 2-2 of DNV-RP-C203 (2016).The script on the following link can be used to plot S-N curves: