Hoop stress

Hoop stress is mechanical stress applied in a direction perpendicular to the radius of the item in question. Along with axial stress and radial stress, it is a component of the stress tensor in cylindrical coordinates.

The classic example of hoop stress is the tension applied to the iron bands, or hoops, of a wooden barrel. In a straight, closed pipe, any force applied to the cylindrical pipe wall by a pressure differential will ultimately give rise to hoop stresses. Similarly, if this pipe has flat end caps, any force applied to them by static pressure will induce a perpendicular axial stress on the same pipe wall. Thin sections often have negligibly small radial stress, but accurate models of thicker-walled cylindrical shells require such stresses to be taken into account.