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: σ r e d = ( σ 2 ) + 3 ( τ 2 ) {\displaystyle \sigma _{red}={\sqrt {({\sigma }^{2})+3({\tau }^{2})}}} where σ {\displaystyle \sigma } is the tensile stress, and τ {\displaystyle \tau } is the shear stress, measured in newtons per square meter (N/m2, also called pascals, Pa), while σ r e d {\displaystyle \sigma _{red}} —called a reduced tension—is the resultant tension of the material.