Strain energy

In physics, the elastic potential energy gained by a wire during elongation with a tensile (stretching) or compressive (contractile) force is called strain energy. For linearly elastic materials, strain energy is:

${\displaystyle U={\frac {1}{2}}V\sigma \varepsilon ={\frac {1}{2}}VE\varepsilon ^{2}={\frac {1}{2}}{\frac {V}{E}}\sigma ^{2}}$

where σ is stress, ε is strain, V is volume, and E is Young's modulus:

${\displaystyle E={\frac {\sigma }{\varepsilon }}}$