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:<ref>Huber, M. T. (1904). "Właściwa praca odkształcenia jako miara wytezenia materiału". Czasopismo Techniczne. Lwów. 22. Translated as "Specific Work of Strain as a Measure of Material Effort". Archives of Mechanics. 56: 173–190. 2004.</ref>

<math> \sigma_{red}=\sqrt{({\sigma}^2) + 3({\tau}^2)} </math>

where <math>\sigma</math> is the tensile stress, and <math>\tau</math> is the shear stress, measured in newtons per square meter (N/m², also called pascals, Pa), while <math>\sigma_{red}</math>—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.

See also

• Yield surface
• Stress–energy tensor
• Tensile stress
• von Mises yield criterion