Creep is defined as what?

• A. Time-dependent permanent deformation under constant stress
• B. Immediate rupture under impact
• C. Elastic deformation only
• D. Fatigue under cyclic loading

Answer: (A)

Creep is the time-dependent permanent deformation that occurs when a material is held under a constant applied stress, usually at elevated temperature. As time passes, atoms and dislocations rearrange, allowing the material to continue deforming even though the load hasn’t changed. This deformation is largely irreversible, so when the load is removed, much of the strain remains as a permanent set.

This distinguishes creep from the other concepts: immediate rupture under impact is a rapid fracture event, not the slow, time-driven process of creep; elastic deformation is recoverable when the load is removed, not permanent; and fatigue arises from repeated loading cycles, not a steady constant load.