Creep is characterized by which of the following?

• A. Sudden impact
• B. Sustained mechanical stress
• C. Thermal cycling
• D. Moisture absorption

Answer: (B)

Creep is a time-dependent deformation that happens when a material is held under a constant mechanical stress. The key idea is that deformation accumulates gradually over time, especially as temperature rises or stress levels are sustained for long periods. This distinguishes creep from a sudden impact, which causes an immediate change in shape, and from thermal cycling or moisture absorption, which involve rapid temperature changes or diffusion-driven swelling rather than continuous deformation under a steady load. In practical terms, a component under a constant load will slowly creep, with the rate influenced by the magnitude of the stress, the temperature, and the material’s internal structure.