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S/N Curves in MMPDS-15

S/N Curves in MMPDS-15

S/N Curves in MMPDS-15

Hi Guys,
I noticed that on page A-7 of MMPDS-15, it is written that "S/N Curves are for a 50 percent probability of survival. We usually assume conservatively few fatigue penalization factors (such as anodizing + shot-peening, surface finish, ...). But, I would like to know if you apply another reduction factor on the S/N Curves of MMPDS to have a better confidence level? If you reduce these curve then please let me know what is your reduction factor? I appreciate if you can share your experience.
Thank you,

RE: S/N Curves in MMPDS-15

MMPDS Section Estimation of Lower Tolerance Bounds for Fatigue Data describes a procedure to calculate a 99/95 fatigue curve from the information presented in the Handbook. It will shift your fatigue curve to the left (reducing the life at a given stress) by a multiple of the standard error. Your other influence factors would need to applied on top of that.


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