Plane stress

In real engineering components, stress (and strain) are 3-D tensors, however when one of the dimensions of the material is much smaller than the other two, it can be neglected and the resulting state of stress becomes bidimensional.^[1] This state is known as plane stress because the normal, σ₃₃, and shear, σ₁₃ and σ₂₃, stresses with respect to the thin surface are zero. Examples of such materials include thin-walled structures such as plates subject to in-plane loading or thin cylinders subject to pressure loading. The stresses are negligible with respect to the smaller dimension because the stresses are not able to develop within the material and are small compared to the in-plane stresses.^[1]