Question

The area under the linear curve of stress-strain diagram with in the elastic limit is known as

• A. Strain energy
• B. Kinetic energy
• C. Potential energy
• D. Gravitational energy

Hint:

Area under the $\sigma$-$\varepsilon$ curve within the elastic limit = Resilience (or elastic strain energy per unit volume). If the area is calculated across the entire curve up to the point of fracture, it represents the material's Toughness.

Answer 1

The Correct Option is A

Imagine stretching a spring gently within its elastic range and then releasing it, it snaps back completely because the work you put in is stored as recoverable energy rather than lost as heat. On a stress strain diagram, that stored recoverable work per unit volume is exactly what the area under the curve represents. Since the elastic portion of the curve is a straight line from the origin, the area under it is simply a right triangle, half of stress times strain. This stored, recoverable quantity is called strain energy, and it is different from kinetic energy which needs motion, or potential energy in the usual gravitational sense, so the correct term is strain energy.