Creep and Static Fatigue: What's the Distinction?

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SUMMARY

The discussion clarifies the distinction between creep and static fatigue, emphasizing that static fatigue is specific to ceramics and glasses, characterized by failure due to water vapor and residual stresses. Creep, on the other hand, occurs in materials like glass and concrete, albeit at a very slow rate. Historical examples, such as the ripple effect in old glass, illustrate the long-term effects of creep. The mechanisms of failure in static fatigue resemble stress corrosion cracking in metals, with plastic deformation not being a factor in ceramics.

PREREQUISITES
  • Understanding of static fatigue in ceramics and glasses
  • Knowledge of creep behavior in materials like concrete and glass
  • Familiarity with stress corrosion cracking mechanisms
  • Basic principles of material science and mechanical properties
NEXT STEPS
  • Research the mechanisms of static fatigue in ceramics and glasses
  • Study creep behavior in concrete and its implications in construction
  • Explore stress corrosion cracking in metals, particularly aluminum
  • Investigate historical examples of creep in glass and its manufacturing processes
USEFUL FOR

Material scientists, engineers, and students studying mechanical properties of materials, particularly those interested in the long-term behavior of ceramics, glasses, and concrete under stress.

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What is the difference between these two phenomena? Or are they the same thing?

I have heard both terms used in different classes, but they seem to be the same or similar.
 
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Static fatigue is a term limited to ceramics and glasses. The loading is similar to a standard creep test i.e. static tensile load, but the failure is usually dependent on water vapor being present in the air.

According to my trusty materials handbook, the mechanism for failure is similar to stress corrosion cracking of metals. It also states that this mode of failure will not occur in a vacuum.
 
Ok, then static fatigue in ceramics is actually referring to failure by cracking due to residual/constant stresses. Then plastic deformation is not a consideration here.

Do glasses and ceramics exhibit creep at all?
 
Glasses and ceramics (e.g. concrete) do creep. The creep rate is very, very slow.

If one looks at old glass from the 1700's and 1800's, one may notice a ripple effect. This is due to very slow flow - mm/decades or mm/centuries.

Concrete under compression will flow.
 
Fatigue also occurs in metals such as aluminium. Cracking is mostly caused by the loading and unloading of forces.
 
actually it the rate is much slower, old glass ripples is almost always due to manufacture/nonsupercooled fluidity related phenomena
 

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