Tension field theory and the stress in stretched skin

Tension field theory is generalized to membranes undergoing arbitrarily large deformations. The theory is used to model operations on the human skin performed by plastic surgeons. It is shown that the tension rays are geodesics of the surface over which the skin slides. The theory is applied to a plane sheet having an elliptical hole which is closed into a straight line coinciding with its major axis, to obtain a formula for the maximum stress on a closed skin defect. The theory is also applied to a model for the Z-plasty operation, and the theoretical equations are compared with published experimental results.