Alternating Stress Formula
Alternating Stress Formula
(OP)
I have been looking for the formula for alternating stress. It's the formula for fatigue analysis whereby "R" is the variable and ranges between R = -1 (full reversible stress; Fmin = -Fmax) and R = 1 (Fmin = Fmax... static load). The formula is some function of Fmin and Fmax but it is NOT (I don't think...) R = Fmin/Fmax since both Fmin and Fmax can be zero. If that IS the formula, then I need more understanding of the definition of Fmax and Fmin. Thanks.





RE: Alternating Stress Formula
Fmean = (Fmax+Fmin)/2
RE: Alternating Stress Formula
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I don't know the answer to the question "what is the R ratio when the maximum stress is 0 and there is a divide by 0 error?".
RE: Alternating Stress Formula
RE: Alternating Stress Formula
Some are the Goodman, Soderberg and Gerber formulations wish use the mean and alternating stress in their relationships.
Those equations can be easily transformed to R factor relations replacing it's definition on the formulae.
take a look at this link:
http://www.utm.edu/departments/engin/lemaster/Machine%20Design/Lecture%2010.pdf
regards.