Tensile stress and strain

Here are the definitions for tensile stress and strain:

• Tensile stress ($\sigma$) is the force applied perpendicularly to the cross-sectional area of a material when it is being stretched. It is a measure of the internal forces that particles within a continuous material exert on each other.

$$\sigma = \frac{\text{Tensile Force}}{\text{Cross-sectional Area}} = \frac{F}{A}$$

The SI unit for tensile stress is the pascal ($\text{Pa}$), which is equivalent to newtons per square meter ($\text{N/m}^2$).

• Tensile strain ($\epsilon$) is the fractional change in length of a material when it is subjected to a tensile force. It is a dimensionless quantity, representing the deformation of the material relative to its original size.

$$\epsilon = \frac{\text{Extension}}{\text{Original Length}} = \frac{\Delta L}{L_0}$$

Since strain is a ratio of two lengths, it has no units.