Huber's equation

Huber's equation, first derived by a Polish engineer Tytus Maksymilian Huber, is a basic formula in elastic material tension calculations, an equivalent of the equation of state, but applying to solids. In most simple expression and commonly in use it looks like this:

$$ \sigma_{red}=\sqrt{({\sigma}^2) + 3({\tau}^2)} $$

where $$\sigma$$ is the tensile stress, and $$\tau$$ is the shear stress, measured in newtons per square meter (N/m2, also called pascals, Pa), while $$\sigma_{red}$$—called a reduced tension—is the resultant tension of the material.

Finds application in calculating the span width of the bridges, their beam cross-sections, etc.