The recent progress of the performance of sailing yachts has been driven by thecontinuing use and development of lightweight sandwich structures made ofpolymeric composite materials. So far the structural design of sailing yachts hasrelied on static or quasi-static approaches which usually lead to conservativedesign. Sailing yachts undergo several diverse dynamic loads in a seaway. Rigsand rigging, deck and hull have to be designed to withstand local and distributedloads whose entity is always difficult to determine. In this respect, the phenomenonof slamming, namely the impact of the hull bottom against the water surface in arough sea, and its effects on the structure represent a crucial issue.This implies that when structural optimisation is required it is necessary to betterdefine the external loads and the strain-rate properties of the material utilized.With this in mind, this thesis explores the dynamic response of a FRP (fibrereinforced plastics) sandwich hull panel subject to slam loads.This is achieved initially by investigating experimentally the dynamic properties ofFRP under rates of strain typically experienced by sailing yacht structures. Asystematic methodology is then proposed to describe the strain-rate behaviour ofthe material by LS-DYNA explicit finite element code. This methodology issubsequently applied to examine the response of a hull panel to a slam load.It is shown that the ALE (Arbitrary Lagrangian-Eulerian) method, within LSDYNAcode, is suitable to model the fluid-structure interaction slam problem andto assess the relative entity of the load to be used in the panel analysis.A static finite element analysis of the panel is also carried out based on standarddesign rules. Results are compared with the dynamic approach presented and theconservativeness of the static method is underpinned.Developing the knowledge of both the dynamic properties of the materials and theuse of tools such as explicit finite element codes is shown to be a valid approach tooptimise the design of sailing structures under slam load.
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