Fatigue Cycle Counting ASME VIII Div 2, ANNEX 5B

Question

Fatigue Cycle Counting ASME VIII Div 2, ANNEX 5B

Doodler3D (Mechanical)

(OP)

9 Oct 20 20:25

Hi,

I was going through the PVEng samples on their website. I noticed that they performed FEA using the pressure based on single event of 100 psi, even though the stress range was between 25 psi to 125 psi. This does not conform to ASME VIII Div 2, ANNEX 5B? I'm not sure what to make of the statement in the report - 'All internal surfaces have 100 psi applied. This pressure simulates the same stress amplitude as running 25 psi to 125 psi and calculating the stress differential per VIII-2.'

Thank you!

Document:
https://www.pveng.com/wp-content/uploads/2016/06/F...

Relevant picture:

This post is to clear a doubt and not undermine the authors efforts.

rb1957 (Aerospace) · Answer 1 · 2020-10-09 21:35:20

I think what they are saying is that (with linear elastic FEA) applying a load of 100psi gives you the stress range of the fatigue cycle (of 125psi to 25psi).
and you can use stress range to do fatigue calc (stress range = 2*alternating stress).

another day in paradise, or is paradise one day closer ?

Doodler3D (Mechanical) · Answer 2 · 2020-10-12 15:44:14

RE: Fatigue Cycle Counting ASME VIII Div 2, ANNEX 5B

Doodler3D (Mechanical)

(OP)

12 Oct 20 15:44

@rb1957 , thank you.

Answer 3

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Fatigue Cycle Counting ASME VIII Div 2, ANNEX 5B