Section 8 Div 2 Alternating Equivalent Stress Amplitude
Section 8 Div 2 Alternating Equivalent Stress Amplitude
(OP)
I am checking a report and it appears the author is multiplying equation 5.36 by Young's Modulus ambient divided by Young's Modulus at operation temperature. Is this from an older version of the code? I can not find the Young's Modulus ratio anywhere in the code.
.5 * (Kf * Ke * deltSpk) * E/E
.5 * (Kf * Ke * deltSpk) * E/E





RE: Section 8 Div 2 Alternating Equivalent Stress Amplitude
Is it possible that the original calculation of delSpk did not have a Young's modulus correction, and this was a convenient place to do such a correction? Seems odd, though...
RE: Section 8 Div 2 Alternating Equivalent Stress Amplitude
RE: Section 8 Div 2 Alternating Equivalent Stress Amplitude
RE: Section 8 Div 2 Alternating Equivalent Stress Amplitude
RE: Section 8 Div 2 Alternating Equivalent Stress Amplitude
Also, it should be noted that although there is nothing mathematically wrong with using natural logarithms in the interpolations to find S-N from Si,j-Ni,j, the Code specifically says to use logarithms with base 10.
I must compliment you on your thorough checking job. Finding errors like this sometimes requires a fine-toothed comb - something most engineers who do ASME Section VIII, Division 2, Design-By-Analysis may be capable of, but even experienced vessel engineers have troubles with.
I recommend asking the analyst directly your questions. You will be able to tell right away if you should trust them or not. If they are defensive, our try to apply the "Position of Authority" card with you, run. If they engage you, explain what they did, and how/why they did it in a collegial manner, you have someone that you can work with. Trust your instincts in this. They _may_ have more knowledge about FEA for vessels/piping than you do, but you're no slouch/idiot.
RE: Section 8 Div 2 Alternating Equivalent Stress Amplitude
RE: Section 8 Div 2 Alternating Equivalent Stress Amplitude