fatigue curve creation using ASME VIII Div 2
fatigue curve creation using ASME VIII Div 2
(OP)
Good Evening To ALL
Can any one please guide me how to create Fatigue Curve with help of ASME VIII Div 2.
Thanks & Regards
Senthil
Can any one please guide me how to create Fatigue Curve with help of ASME VIII Div 2.
Thanks & Regards
Senthil





RE: fatigue curve creation using ASME VIII Div 2
RE: fatigue curve creation using ASME VIII Div 2
There's much more to a fatigue analysis than just an S-N curve, though, as mentioned by BenStewart.
RE: fatigue curve creation using ASME VIII Div 2
Thanks for your reply. From ASME VIII-2 Equation 3.F-1, 3.F-2 & 3.F-3 will give you only one parameter as N. To construct the S N curve we need coordinate for each points(A , B & C) as shown in Figure as example (Refer the attachments).IF I want create Point A I need X value and Y value, similar way Point B & C . How to find X & Y parameters.
RE: fatigue curve creation using ASME VIII Div 2
For Welded Joint - There's another simple calculation method and it's described in 3-F.2.2. Not sure what you're doing but you're instructed to use the date for mean less three standard deviations.
I personally don't know the changes being made for the future Editions, but, regardless, I'd suggest reading the following to get a feel for fatigue analyses using ASME VIII-2:
1. ASME VIII-2 - Specifically, Part 5.5 and Annex 3-F.
2. ASME PTB-1 - There's a good narrative around Part 5.5.
3. This forum - loads of useful information from experiences Engineers.
4. Reliable sources on the internet - as a samples, here's two interesting articles: https://becht.com/blog/fatigue-evaluation-of-welde..., http://paulin.com/Library/Fatigue_Info/Hinnant_ASM...
Hope that helps.
RE: fatigue curve creation using ASME VIII Div 2
Your figure indicates an "endurance limit" for steels. The data (from about the early 1990's) shows that such an endurance limit doesn't exist. The slope of the S-N curve is still negative out to 10^11. This has been reflected in the ASME fatigue curves for a while now.
Equations 3-F.1 through 3-F.3, in conjunction with Tables 3-F.1 through 3-F.8 (the C_n parameters come from the Tables), will provide you with the full curve. However, in order to fully implement the curve, you need to know the average temperature of the point of interest over the "cycle". That will provide you with the adjustment necessary, because all S-N curves are actually strain-life curves, and to make them into stress-life curves they need to be multiplied by Young's Modulus, which is a function of temperature.
RE: fatigue curve creation using ASME VIII Div 2