Following are the formulas relating to simple stresses and strains.

\(Stress\space\ = \frac{force}{Area}\)

\(Strain\space\ = \frac{Increase\space\ in\space\ length}{Original\space\ length}\)

**Young’s Modulus of Elasticity**

\(Young’s\space\ Modulus\space\ = \frac{Stress}{Strain}\)

\(Posion’s\space\ Ratio\space\ =\frac{1}{m}\)

\(Volumetric\space\ Strain\space\ = \frac{Change\space\ in\space\ volume}{Original\space\ volume}\)

**Proportional Limit Stress**

\(Proportional\space\ limit\space\ stress\space\ = \frac{Proportional\space\ limit\space\ stress}{Area}\)

\(Ultimate\space\ stress\space\ =\frac{Ultimate\space\ load}{Area}\)

\(Actual\space\ breaking\space\ stress\space\ = \frac{Breaking\space\ load}{Final\space\ area}\)

\(Nominal\space\ breaking\space\ stress\space = \frac{Breaking\space\ load}{Original\space\ area}\)

\(Percentage\space\ Elongation\space\ =\frac{(Final\space length\space\ -\space\ Original\space\ length)\times 100}{Original\space\ length}\)

\(Percentage\space\ reduction\space\ = \frac{(Original\space\ area\space\ -\space\ Final\space\ area)\times 100}{Original\space\ area}\)