Symbol a
a is part of the quantity the equation computes from the expression on the right.
Read this term in its guide →Published equation contexts
Why this formula appears here
The governing correlation is empirical. Paris and Erdogan proposed that crack growth per cycle depends on the range of the stress intensity factor over the cycle: . The parameters C and m are fitted, not derived, and depend on environment, frequency, temperature and stress ratio. A mechanics review that proposes a generalised form of the law opens by conceding that “fatigue life prediction is still very much an empirical art rather than a science”, and notes that the power law holds only in an intermediate regime, deviating near the threshold below which cracks do not propagate and again in the fast-growth stage approaching final fracture [ 6 ] . The same review sets out…
Read the representative guide
Symbol N
N occurs below the fraction bar. The quantity above the bar is divided by this expression; zero is excluded as a denominator.
Read this term in its guide →Symbol Δ K
Δ K is an input to the expression that computes the quantity on the left.
Read this term in its guide →Symbol m
fitted, not derived, and depend on environment, frequency, temperature and stress ratio.
Read this term in its guide →Denominator: dN
The complete quantity below the fraction bar; it must be nonzero for this division.
Read this term in its guide →How to interpret it
With a fixed numerator, increasing a nonzero denominator reduces the fraction. Read it with the definitions, units, and assumptions supplied by the article.
Research cited beside this formula
Published contexts (1)
A symbol can carry a different meaning in another article. Each occurrence keeps its own guide and term definitions.
Equation 20 · Materials Science
Why Materials Fail: Fracture, Flaws and the Inspection Interval
This equation states an equality: the expressions on both sides have the same value under the article’s assumptions.
The governing correlation is empirical. Paris and Erdogan proposed that crack growth per cycle depends on the range of the stress intensity factor over the cycle: . The parameters C and m are fitted, not derived, and depend on environment, frequency, temperature and stress ratio. A mechanics review that proposes a generalised form of the law opens by conceding that “fatigue life prediction is still very much an empirical art rather than a science”, and notes that the power law holds only in an intermediate regime, deviating near the threshold below which cracks do not propagate and again in the fast-growth stage approaching final fracture [ 6 ] . The same review sets out…
Meanings in this article
- : the parameters.
- : fitted, not derived, and depend on environment, frequency, temperature and stress ratio.