Application of a non-convex model of fabric deformations to sail cut analysis

In this paper, we present a computer model based on an elastic string network representation for sail deformation. The equilibrium equation for this model is written in the form of a minimization problem. The latter is non-convex because of the unilateral-stress behaviour of strings. The method of deconvexplication has to be used in order to obtain an equivalent problem which is easier to solve. The resulting model is applied to sail cut design problems: bi- and tri-radial cut plans are compared, as well as variations of the elasticity modulus in warp and weft directions. The results are found to be very similar to what is usually observed on actual sail boats.