Calculating Stress Range For Fatigue Exemption

[Paulettea]

Dear all

Based on ASME Sec.VIII Div-2,I have performed calculations for exemption of a vessel from detail fatigue calculations. In my calculations Method A screening criterion could not exempt the vessel however, by applying method B the vessel was exempted from fatigue calculations.
I sent the calculation document to be reviewed then the reviewer of the document has rejected the document for the following reason:
"Fatigue of pressure parts is subject to stress range, stress range should be calculated before starting screening method"
Furthermore, he continues to ask for development of a histogram via cycle counting method of rainflow. He also wants me to calculate the stresses due to combined effects of temperature gradient and mechanical loads.

I think this comment is totally wrong since if I am supposed to do a detailed stress analysis and then apply rainflow or other methods of cycle counting in advance, then it would not be called an exemption method.

Can you please help me understand what the comments mean?

Warm Regards

 

[TGS4]

Your reviewer doesn't understand the concepts behind Method B. Find a different reviewer. What they're asking for is an actual fatigue analysis.

 

[Paulettea]

Thank you TGS4

Now I feel much safer. One more thing about his comments is that he claims that if you want to exempt an equipment from detailed fatigue calculations you need to exempt it from both methods A and B. I do not know how to deal with this guy.

Warm Regards.

 

[TGS4]

The rules explicitly say Method A OR Method B. Perhaps a second, outside opinion would sway them.

 

[DSB123]

Tell the reviewer to actually read and understand the Code screening methods!!

 

[SnTMan]

A client to understand the Code? Or even his own specifications? DSB123, you're dreaming

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[DSB123]

SnTMan,
As far as the thread is concerned I do not see anywhere it states that the "reviewer" is the Client - It could be a third party!!

 

[SnTMan]

Yeah, could be, my remark still applies. Get this all the time. Client, reviewer, whoever comes across something in a document he/ she / it does not understand. Pick up the phone and ask a question? NO. Mark up and return. Extra round of work for everyone. Might be a third party after all

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Paulettea]

This reviewer is a third party. The problem is that in many occasions I have seen that clients normally buy the words of third party more than the manufacturer. It is easier for them to trust the third party.

Warm Regards

 

[MrPDes]

If you are not able to select the reviewer which is often the case, you will need to Diplomatically/sarcastically/assertively teach the reviewer how to do the job that they are supposedly experts at.

It is frustrating giving someone outside you company a free education. Especially as they always resist and rarely show appreciation for the education that you have provided them.

 

[DSB123]

Basic problem is there are one hell of a lot of "Bullsh** Merchants" in the engineering game - even some as Members of Institutes. Institutes are now mainly after Subs and not quality!!!