Problem:

Nominal yield strength (σ_e) is not calculated as per EN13445-3 Clause 8.4.3 eq 8.4.3-1, Why?

For example, Lower shell, the Rp1.0% = 181 MPa, therefore the elastic limit = 181 /1.3 = 139 MPa. In the calculation we find 111.38 MPa.

We don't understand where this value comes from?

Solution:

Nominal yield strength value shown in report is correct.

Refer clause 8.4.3, Note clearly says if the value of Rp 0.2 is unavailable a safe estimate is Rp 1.0/1,3.

In this case (Operating condition),

Rp 1.0 = 181 MPa

We have value Rp 1.0 (1,0 % proof strength) and not Rp 0.2 (0.2 % proof strength at temperature T), Hence as per note in clause 8.4.3,

Rp 0.2 = 181 / 1.3 = 139.23 MPa

And Now as per Equation 8.4.3-1,

σ_e = Rp 0.2 / 1.25

σ_e = 139.23 / 1.25 = 111.38 MPa

As you can see calculated value of nominal yield strength is matching with reported value, results are correct.