Large displacement analysis for ideally flexible sails

We consider the equilibrium of a sail under a given aerodynamic field of external forces. The sail is considered to be an ideally flexible structure, having the behaviour of a network of stress unilateral strings: all the internal efforts are traction efforts. This model leads to a Non Convex Optimisation Problem and a complete theory can be established, leading to relevant results of uniqueness for the field of stresses, even if configurations of equilibrium are not unique.