The benefits, potentiasl and possibilities of using composite materials in ship design have led to new challenges and research areas in the shipping industry.
The objective of the project is to propose a procedure how to select the most optimal composite material and structure with respect to weight and cost. The materials can, for example, be glass or carbon fibre reinforced polyester or epoxy and the structures can be sandwich or single skin, or combinations of both of them. In the project, some typical ship structures will be studied with respect to optimized weight and cost using different materials; a typical structure that is studied is a bottom panel with stiffeners. Labour cost will also be incorporated in the evaluation.
This project studies the possibilities to optimise, in a rational and effective way, parts of a ship or the entire ship using composite structures. In the investigation, structural characteristics, weight, cost and LCA and LCC are incorporated.Glass fibre reinforced plastics (GRP) have for a long time been used in boats and leisure crafts. In these applications the advantages, such as low manufacturing cost and almost no need for maintenance, are obvious and well-known. The use of composites in larger vessels has been limited to some very special applications such as naval mine hunters.
An important contribution from the research project is to systematically summarise and categorise the different materials with respect to structural characteristics, potential cost and weight saving, etc. The most promising alternatives will be focussed on to make them usable in real ship design.
The calculations and the designs in the project will be based on classifications rules, for example the DNV HSLC code, since the overall goal is to have results that can be used directly by designers and shipyards.
The objective is to identify potentials and drawbacks of the different materials with respect to strength characteristics, their relative cost of weight saving compared to a steel structure solution. In many cases low cost and low weight are contradictory.
Composites can easily be shown to have great advantages over metals and wood in shipbuilding. Maintenance cost can be reduced to 10% of the maintenance cost for a similar steel hull. Additionally, the weight can be reduced to 50% of the weight of a similar steel hull. Over a lifecycle the total cost for operating a composite ship is substantially lower, much dependent on fuel prices. In addition, as fuel prices increase and the environmental issues become more important, composites also become more attractive to other types of ships and ship structures, such as ferries, non-military patrol craft and super structures for commercial vessels. However, a conversion from steel material to composites is not trivial since a direct substitution of material or sandwich structure cannot be made based on “traditional” knowledge and design criteria. Ship building and structural integrity analysis has to be further developed when using composites. Additionally, other variables such as material cost, fire-proof regulations and governmental rules must also to be taken into account.
Håkansson, M. (2010). Use of carbon fibre in high speed passenger ferries. Proceedings of the RINA conference Marine & Offshore Structures in London, U.K., February 3-4, 2010.