Dear All,

We have carried out local load analysis of a cylindrical shell (Design code: ASME Sec VIII Div.2 2015) at the location of a pad attached to it as part of the support lug attachment. The PV Elite calculation is attached herewith.

1. Attention is drawn to the page 26 (Test Case). Where vessel stress summation comparison at reinforcing pad edge values are indicated. For Pm (SUS+OCC) (Type of stress Int.), the max. S.I is indicated to be 411.50MPa, whereas the S.I allowable is indicated as 344.76MPa (which works out to be 1.2 times the allowable S.I value of 287.30MPa at 121-degree Celsius design temperature).

2. The case being "hydro test condition" why the S.I allowable is not considered as 0.95 x 517.12MPa (Yield strength of AISI 4130, which is the cylindrical shell material) = 491.2MPa [inline with ASME Sec VIII Div.2 2015 - Article 4.1.6.2.(a).(1) [page no. 156].

Request your views, please!!

Regards

Mohammed Elias D

Hello Mohammed,

You are quite right, the allowable used in the test calculation should be a function of the 'hydrotest' allowable stress as it appears in the material properties dialog. Depending on the selected Code and user options, the value could be 90% Sy, 95% Sy, 1.3*Sa, etc.

In fact this issue was very recently addressed and will be fixed in PV Elite 2017. Currently the allowable is based on the cold allowable stress which is conservative.