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wijeesh
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Engineering Fields - Mechanical Engineering - New Member

Join Date: Apr 2008
Location: India
Posts: 25

Fatigue Analysis

11/21/2011 1:05 AM

Dear All

How this fatigue analysis is performed for a U2 vessel. Is there any commonly used softwares? also is this analysis required for the whole vessel or only for nozzles/shell junctions.?

in my case
shell material - SA 516 Gr 70
pressure cycles - 100 cycles
Temperature cycles - 1500 cycles
Design life - 30 years


please help


Regards
vGsh

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MJCronin
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Location: Central Midwest
Posts: 455
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#1

Re: Fatigue Analysis

11/21/2011 8:18 AM

Your question really is all about the "Code of construction" selected for the vessel that you want to build.

In the USA, the most commonly used code of construction is ASME VIII. Fatigue analysis is performed in accordance with the rules of Division #2. India has similar rules.

The pressure vessel designer does not realy have the authority to pick and choose any analysis methods that he wants.

If your vessel only has 100 pressure cycles over 30 years, an ASME VIII; Division 2 fatigue evaluation is not necessary. Division 1 rules will suffice.

I have only encountered a pressure vessel fatigue analysis being required for process services such as "pressure swing absorbtion". In PSA, the vessels undergo many full cycle pressure swings in a single day.

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RVZ717
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United States - Member - USA! Hobbies - Musician - Sound Man Engineering Fields - Mechanical Engineering - More than a Hobby Technical Fields - Technical Writing - New Member

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#2

Re: Fatigue Analysis

11/21/2011 3:00 PM

As already stated, This IS an exact science, and the specifications/laws/regulations are very strict, and written in black and white. Everything you need to know is written in the codes and MUST be adhered to.

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wijeesh
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Engineering Fields - Mechanical Engineering - New Member

Join Date: Apr 2008
Location: India
Posts: 25
#3

Re: Fatigue Analysis

11/21/2011 11:39 PM

thank you for your reply..

i agree pressure cycle is below the limits.. but tempereture cycles are >1000.

As per sec. 5.5.2.3, it requires fatigue analysis (please advise)

Regards

vGsh

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