Plane Stress

Plane stress refers to a condition in thin materials, like a sheet of metal or paper, where stress (force per unit area) occurs mainly in two dimensions—length and width—while stress through the thickness is negligible. Imagine pressing down on a thin cardboard, causing it to stretch or compress in its surface plane, but little to no force acts along its thickness. This concept simplifies the analysis of the material’s behavior under loads, making it easier to predict deformation and failure in structures like airplane wings or car bodies, where the material’s thickness is small relative to its other dimensions.