Structural design, sizing and optimisation for a foiling monohull

Abstract

The unique geometry of the large-scale, fully foiling, monohull yachts, which will be raced in the 36th America's Cup, present several opportunities for novel structural engineering solutions. In order to facilitate these new solutions, new design tools are required. Struc-tural design tools have been developed to enable the design, sizing and optimisation of the internal structure of the hull. The primary goal of the structural design of the hull is to develop a lightweight structure which is capable of withstanding the loads encountered during racing. A range of software tools has been developed, which enable the designer to produce lightweight structural concepts, at each stage of the design process. As the design progresses, so it's scope narrows. In the initial stages of design, two of the key considerations were; how many bulkheads to use and which curved regions could feasibly be constructed using a monolithic construction as opposed to a sandwich con-struction. As the design process continued, consideration was given to how to determine the size of the panels, how to size the sti˙eners, where to place them and ˝nally, what stacking sequence to use in the panels. Software tools, underpinned by parametric Finite Element models, have been developed in order to answer these design questions. The design and sizing tools were implemented by running a series of iterative FE analyses and synthesising the results to determine the required sizes. The lay-up optimisation method was developed through the use of a custom Genetic Algorithm (GA.) The Genetic Algorithm was also used in combination with an Arti˝cial Neural Network (ANN) in order to optimise the layout of the panel sti˙eners. It has been shown that these tools enable signi˝cant weight savings to be achieved, compared with conventional design methods.