The reinforcement for holes in tensile stress fields sometimes takes the form of an extensive thin plate attached to the sheet, especially if the reinforced region is of integrally machined or bonded construction. Such reinforcements are often placed eccentrically, that is on one side of the sheet only. It has been shown both experimentally and analytically that such an eccentrically placed reinforcement can promote considerable bending stresses.

Wittrick gives curves showing the effect of eccentricity in the case of the circular hole with an eccentrically located annular plate reinforcement in a plane, axially symmetric stress field. High, but only local, bending stresses exist which simple theory will not predict. The stresses are markedly higher than those given with the corresponding symmetric reinforcement. For example, under axisymmetric loading it is possible to design an optimum plate-reinforced neutral hole (i.e. the stress concentration factor is 1·0 in both sheet and reinforcement) if the reinforcement is deposed symmetrically about the plane of the sheet. If however it is placed totally eccentrically then for realistic sheet stresses bending raises the sheet concentration factor 2·0.