Elastic behaviour of a stretched woven cloth

A woven cloth under stretching generally shows an initial range of strain for which stress remains low, followed by a region of rapid increase of apparent modulus at higher strain. Often attributed to the presence of slack, or superfluous unloaded zones, we show here that this behaviour is an intrinsic phenomenon related to the geometry of the structure. Even with a linearly elastic material and slack absent, the initial stress/strain curve should have a low gradient, only to increase later. This phenomenon, analysed using strain energy as the criterion for equilibrium and stress evolution with strain, is an intrinsic, geometrical property of a woven structure.