The time-dependent permanent deformation that occurs under stress; for most materials it is important only at elevated temperatures.
Creep at room temperature is more common in plastic materials and is called cold flow or deformation under load.
There are three main phases of creep:
- First stage starts at a rapid rate and slows with time.
- Second stage creep has a relatively uniform rate.
- Third stage creep has an accelerating creep rate and terminates by failure of material at time for rupture.