The creeping is the phenomenon of deformation in materials which have been under load for several time. When the load is put on the material, initially it deforms but when the load is not removed, it causes a small amount of deformation which increases with time. so answer is C

Creeping

Creeping is the phenomenon of progressive extension of a material under a constant load over time. It refers to the slow and time-dependent deformation of a material at high temperatures and under constant stress. This phenomenon is commonly observed in materials such as metals, polymers, ceramics, and concrete.

Explanation:

When a material is subjected to a constant load or stress, it undergoes deformation over time due to the rearrangement of its atomic or molecular structure and the movement of dislocations. This deformation is known as creeping.

Creeping occurs as a result of the diffusion of atoms or molecules within the material, which leads to the rearrangement of its internal structure and the formation of new bonds. This diffusion process is more prominent at elevated temperatures, as it is facilitated by the increased thermal energy.

Creeping can be categorized into three main types based on the temperature and stress conditions:

1. Primary Creep: In the initial stage of loading, there is an instantaneous deformation that occurs rapidly and then slows down over time. This stage is characterized by a decreasing strain rate.

2. Secondary Creep: After the primary creep stage, the deformation becomes more uniform and occurs at a relatively constant rate. This stage is characterized by a steady-state strain rate.

3. Tertiary Creep: As the stress and temperature continue to increase, the material may enter a stage of accelerated deformation. This stage is characterized by an increasing strain rate and eventually leads to failure or fracture of the material.

Creeping is influenced by several factors, including temperature, stress level, and time. Higher temperatures and stress levels increase the rate of creeping, while shorter durations of loading may not allow sufficient time for significant creep deformation to occur.

Creeping can have significant implications in engineering applications, especially in structures and components that are exposed to high temperatures and long-term loading. It can lead to dimensional changes, loss of structural integrity, and reduced lifespan of the material or component.

In conclusion, creeping is the phenomenon of progressive extension of a material under a constant load over time. It is a time-dependent deformation process that occurs at elevated temperatures and can have significant implications in engineering applications.