A practical optimization framework for the structural design of composite hulls

Scantling rules established by international bodies like International Organization for Standardization (ISO) and classification societies play a crucial role in the structural design of marine structures in terms of safety, reliability, and efficiency. Although these guidelines provide straightforward calculations to determine design loads or minimum requirements, such as thickness or section of the modulus, achieving an optimum structural design is still a formidable challenge. Specifically, the structural design of composite hulls comprises a counterintuitive design space, considering material (matrix and reinforcement) and geometric properties (stacking sequence, layer thickness, etc.). This study presents a practical and systematic framework that collates automated finite element simulations and an optimization approach based on response surface methodology (RSM) to determine the optimal structural design for composite hulls. To illustrate the applicability of the proposed methodology, the stiffened bottom plate of a generic motor boat is investigated in detail. The general framework is developed by integrating ANSYS^® DesignXplorer^TM with automated finite element simulations performed using the ANSYS^® Parametric Design Language (APDL). Different optimization strategies are explored and discussed, elucidating the effects of geometric design parameters such as stacking sequence, layer thickness, and spacing between stiffeners.