PV Elite 2010 : WRC 297 : LOCAL SHELL THK

Dear sir,

Subject : WRC 297 calculation of PV Elite 2010.

We have noted that PV Elite-2010 is not doing the WRC 297 calculation by considering local shell thickness, eventhough it is specified.

Please also let us know the stress concentration factors for nozzle and shell to be considered based on which criteria, like radiography etc.

Dear Ketan,

The consideration of local shell thickness in WRC 297 has been addressed, it is available a hot-fix at this time. In future we will package it as a build update (the next one after March 2010) and it will be available on our website.

If you need the hot-fix just send us an email or as a workaround insert a small shell section with thicker plate and put the nozzle on it.

In my opinion, the stress concentration factor is useful for computing peak stresses which are used in the fatigue evaluation. For an elastic analysis you may leave it as 1. But, some users also think that the presence of opening causes an increase in the local primary stresses. So, they may specify a smaller stress concentration factor. If you use WRC-107 and checked the box "Use kn and kb" it will compute stress concentration factor too.

It is up to you what you use.

Mr. Mandeep,

By default, in WRCB-297, value of stress concentration factor shall be 1.0...At the moment it is showing more than 1.0...If any one wants to increase then he/she may...But due to default value more than 1.0, many are using the same as PV Elite default

Mukesh

The stress concentration factor is associated with pressure only, not the local stress computed by WRC 297. WRC 297 does not consider the effects of pressure. There is a check box in PV Elite called: 'Use Division 2 Stress Indices'. Those are the stress concentration factors taken from ASME Section VIII, Division 2.