What phenomenon describes the gradual deformation of solids under constant stress over time?

The phenomenon that describes the gradual deformation of solids under constant stress over time is creep. Creep is particularly relevant in materials that are subjected to sustained loads at elevated temperatures or for extended periods. It occurs as the microstructural changes within a material allow it to deform slowly and continuously when a constant stress is applied.

Creep is significant in various engineering applications, especially in structural and geotechnical engineering where components are required to perform under steady long-term loads. For example, concrete beams or steel structures may exhibit creep behavior, leading to long-term deformations that can affect the serviceability and safety of structures.

Understanding creep is essential for engineers as it helps in predicting the long-term performance of materials and in designing structures that can withstand sustained loads without unacceptable deformations over time. This knowledge is crucial for selecting materials and designs that maintain structural integrity throughout their intended service life.