Cyclic Stress and Material Failure
When cyclic stresses are applied to a material, even though the stresses do not cause plastic deformation, the material may fail due to fatigue. Fatigue failure is typically modeled by decomposing cyclic stresses into mean and alternating components. Mean stress is the time average of the principal stress. The definition of alternating stress varies between different sources. It is either defined as the difference between the minimum and the maximum stress, or the difference between the mean and maximum stress. Engineers try to design mechanisms whose parts are subjected to a single type (bending, axial, or torsional) of cyclic stress because this more closely matches experiments used to characterize fatigue failure in different materials.
Read more about this topic: Cyclic Stress
Famous quotes containing the words stress, material and/or failure:
“Like all weak men he laid an exaggerated stress on not changing one’s mind.”
—W. Somerset Maugham (1874–1966)
“The material was pure, and his art was pure; how could the result be other than wonderful?”
—Henry David Thoreau (1817–1862)
“War is bestowed like electroshock on the depressive nation; thousands of volts jolting the system, an artificial galvanizing, one effect of which is loss of memory. War comes at the end of the twentieth century as absolute failure of imagination, scientific and political. That a war can be represented as helping a people to “feel good” about themselves, their country, is a measure of that failure.”
—Adrienne Rich (b. 1929)