Failure Mechanisms

CREEP

· Under certain conditions of constant stress and temperature, materials may exhibit a time dependent strain under a constant applied load.

· Curve (a) shows a stable response to a load that causes an initial plastic and elastic deformation. The elastic response is recovered when the load is removed.
· Curve (b) shows a time dependent strain (Creep) under constant load. When the load is removed, the elastic strain component is recovered but the initial and the time dependent plastic strain remain, permanently changing the sample dimensions.

From: Courtney, "Mechanical Behavior of Materials,"
McGraw Hill (1990)