Lay-up optimization for the hull of a competition sailing yacht

Deformability and buckling load of yacht in fibers reinforced plastic sandwich depend on the skins stacked sequence. In this work an optimization of the laminae fibers direction of a competition yacht existing design is proposed. This procedure has been divided into three parts (i.e. material characterization; surface model definition; lay-up optimization). First of all a set of unidirectional specimens has been realized, by using the same fibers and matrix (carbon/epoxy) used for the hull as well as the same procedure and workers, in order to characterize the material according to the ASTM D3039, employing strain gage technique. In the second part, by means of an original software in Turbo-Pascal (which uses the half-width value matrix as an input) linked to Pro/ENGINEER, has been possible to obtain the body plan and the surface and finite element models of the sailing yacht for the subsequent analyses. In the third step, an optimization procedure, that uses the results of FE structural analyses in three different navigation configurations, is performed, with the aim to obtain the fibers direction able to minimize the yacht deformability, taking in account buckling loads also. An approximated analytical model has been used in conjunction with a sweep technique in order to evaluate the best of the solutions.