Basquin, Coffin, Manson, Morrow, Smith, Watson, Topper, ... my brain is boiling, but it was a "short lecture" only :-). Nevertheless it was presented very well. I look forward to apply this knowledge.
Hi Peter, I think that this example will help sort it out: th-cam.com/video/uS78C8LZvzc/w-d-xo.html You an ignore the clunky excel parts, but the mean stress sensitive damage parameters are all discussed here.
Professor Barkey, Basquin equation also appears in stress-life approach which use sf' and b as material parameter. In this lecture, strain-life approach use sigma_f' and b among Basquin equation. What's the relation between sf' and sigma_f'? Because these two parameters come from stress-based and strain-based experiment, respectively.
They are curve fitting parameters for each approach, respectively. For the strain life approach, we could think of it as approaching a true fracture stress at 1 reversal. For the stress life approach, stress at essentially zero cycles is difficult to nail down, since you will have plasticity but the stress life approach uses some nominal elastic stress. In the end, it often best to think of them as curve fit parameters.
@@mbarkey.mechanics Thanks your reply, those parameters come from curve fitting of stress-life and strain-life approach, respectively. I just remember that one commercial fatigue code states if we don't have S-N curve data, sigma_f' and b from strain-life approach can be used as alternative to perform fatigue analysis. That's why I'm curious about the relation between sf' and sigma_f' from different approaches.
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Basquin, Coffin, Manson, Morrow, Smith, Watson, Topper, ... my brain is boiling, but it was a "short lecture" only :-). Nevertheless it was presented very well. I look forward to apply this knowledge.
Hi Peter, I think that this example will help sort it out: th-cam.com/video/uS78C8LZvzc/w-d-xo.html
You an ignore the clunky excel parts, but the mean stress sensitive damage parameters are all discussed here.
Voice is too low
Professor Barkey, Basquin equation also appears in stress-life approach which use sf' and b as material parameter. In this lecture, strain-life approach use sigma_f' and b among Basquin equation. What's the relation between sf' and sigma_f'? Because these two parameters come from stress-based and strain-based experiment, respectively.
They are curve fitting parameters for each approach, respectively. For the strain life approach, we could think of it as approaching a true fracture stress at 1 reversal. For the stress life approach, stress at essentially zero cycles is difficult to nail down, since you will have plasticity but the stress life approach uses some nominal elastic stress. In the end, it often best to think of them as curve fit parameters.
@@mbarkey.mechanics Thanks your reply, those parameters come from curve fitting of stress-life and strain-life approach, respectively. I just remember that one commercial fatigue code states if we don't have S-N curve data, sigma_f' and b from strain-life approach can be used as alternative to perform fatigue analysis. That's why I'm curious about the relation between sf' and sigma_f' from different approaches.