Which term means a permanent deformation of a member due to loads that have been placed on a member for a given period of time?

• A. Plan
• B. Pile
• C. Plastic Deformation
• D. Planimetry

Answer: (C)

Permanent deformation occurs when a material is loaded beyond its elastic limit and continues to deform while the load is applied, so the part does not return to its original shape after unloading. This is described as plastic deformation, where the material has yielded and flowed plastically. When a load is held for a long time, time-dependent effects like creep can add additional permanent strain, but the lasting change in shape from such sustained loading is still captured by the idea of plastic deformation. The other terms here don’t relate to material behavior under load: plan and planimetry are about drawing and measurement, and pile is a structural foundation element.