ASTM defines fatigue life, Nf, as the number of stress cycles of a specified character that a specimen sustains before failure of a specified nature occurs.
One method to predict fatigue life of materials is the Uniform Material Law (UML). UML was developed for fatigue life prediction of aluminum and titanium alloys by the end of 20th century and extended to high-strength steels and cast iron. For some materials, there is a theoretical value for stress amplitude below which the material will not fail for any number of cycles, called a fatigue limit, endurance limit, or fatigue strength.
Read more about this topic: Fatigue (material)
Famous quotes containing the words fatigue and/or life:
“I thank heaven that the 4th. of July is over. It is always a day of great fatigue to me, and of some embarrassments from improper intrusions and some from unintended exclusions.”
—Thomas Jefferson (1743–1826)
“Like children, the elders are a burden. But unlike children, they offer no hope or promise. They are a weight and an encumbrance and a mirror of our own mortality. It takes a person of great heart to see past this fact and to see the wisdom the elders have to offer, and so serve them out of gratitude for the life they have passed on to us.”
—Kent Nerburn (20th century)