Allen, TomWynn, DavidLorimer, Tobias2025-01-212025-01-212024https://hdl.handle.net/2292/71072Fibre Reinforced Plastics are increasingly utilised in the form of Large Complex Composite Structures where attributes like efficiency and specific performance are highly sought after. Common usage includes racing yachts, rockets, wind turbine blades and throughout aeroplane structures. However, contemporary design practices can fail to maximise structural efficiency. The benefits of increased efficiency are numerous, but improved system-wide design approaches are required for improved utilisation of Fibre Reinforced Plastics. A holistic early-stage design approach has been developed for the design of LCCSs. It allows the concurrent determination of optimal FRP laminate and structural arrangements in the early stages of LCCS design. It relies on a Genetic Algorithm (GA) -based optimisation approach designed to concurrently determine the optimal stacking sequence, ply orientations, and the ply count for a laminate subject to complex loading. The GA-based optimisation approach was shown to return optimal or nearoptimal solutions in search spaces up to and including 194 billion points. This demonstrates the GA-based optimisation approach’s ability to find near-optimal solutions when they made up less than 0.1% of the search space. The influence of the FRP Failure Criteria (FC) on optimal laminate configurations was also investigated. Puck’s FC was consistently the most accurate and most conservative out of a range of five well-established FC. It has been implemented in the GA-based optimisation approach and is recommended for future use. Experimental testing was undertaken using a newly designed Biaxial Testing Apparatus (BTA) and cruciform specimens optimised using each of the five FC. The testing accompanied and endorsed a series of numerical simulations investigating the ultimate performance of the GA-based optimisation approach. The influence of FC in the optimisation formulation was quantified, and the effectiveness of the GA-based optimisation at a lab scale was confirmed. Finally, a case study was conducted to assess the efficacy of the newly developed approach compared to a contemporary design process for an IMOCA 60 race yacht. While the results demonstrated the effectiveness of the developed method, the primary emphasis remains on the successful development of the early-stage design philosophy.https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htmThesisCopyright: The authorAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/