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

Deformability and buckling load of yacht hulls with fiber reinforced plasti c sandwich structure depend on the stack sequence of the skins. In this wor k an optimization of fiber directions of the laminae for a racing yacht is proposed. This procedure has been divided into three parts (i.e. material characteriz ation, surface model definition, lay-up optimization). First of all a set o f unidirectional specimens has been realized, by using the same fibers and matrix (carboalepoxy) used for the hull as well as the same procedure and w orkers, in order to characterize the material according to American Society for Testing and Materials (ASTM) Standard D3039, employing strain gage tec hnique. In the second part, by means of an original software in Turbo-Pasca l (which uses the half-width value matrix as an input) linked to Pro/ENGINE ER, it has been possible to obtain the body plan and surface and finite ele ment (FE) models of the sailing yacht for the subsequent analyses. In the t hird step, an optimization procedure that uses the results of FE structural analyses in three different sailing configurations is performed, with the aim of obtaining the fiber directions that art: able to minimize the yacht deformability, also taking into account the buckling loads. An approximate analytical model has been used in conjunction with a sweep technique in ord er to evaluate the best of the solutions. (C) 2001 Elsevier Science Ltd. Al l rights reserved.