No abstract

This work demonstrates the advantages of using laser powder bed fusion for producing a rudder bulb of a moth class sailing racing boat via laser powder bed fusion (LPBF). The component was designed to reduce weight using an AlSi7Mg0.6 alloy and incorporated a biomimetic surface texture for drag reduction. For the topological optimization, the component was loaded structurally due to foil wing’s lift action as well as from the environment due to hydrodynamic resistance. The aim was to minimize core mass while preserving stiffness and the second to benefit from drag reduction capability in terms of passive surface behavior. The external surface texture is inspired by scales of the European sea bass. Both these features were embedded to the component and produced by LPBF in a single run, with the required resolution. Drag reduction was estimated in the order of for free stream velocity of . The production of the final part resulted in limited geometrical error with respect to scales 3D model, with the desired mechanical properties. A reduction in weight of approximately with respect to original full solid model from 452 to 190 g was achieved thanks to core topology optimization. Sandblasting was adopted as finishing technique since it was able to improve surface quality while preserving fish scale geometries. The feasibility of producing the biomimetic surfaces and the weight reduction were validated with the produced full-sized component.

No abstract

No abstract

Maritime Shipping emissions represent the 13% of the overall EU greenhouses gas emissions (GHG) of the whole transport sector. It is estimated that they could increase between 50% and 250% by 2050 under a business-as-usual scenario, undermining the objectives of the Paris Agreement. From 2021, the European Commission adopted a series of legislative proposals to achieve climate neutrality in the EU by 2050, including the intermediate target of at least 55% net reduction in GHG emission by 2030. Despite hydrogen is worldwide considered a valid option to reach the emission reduction targets, being part of the IMO strategy also, a common approach to face the design challenges due to hydrogen introduction in waterborne transport is not yet available. Focus of this study is the adoption of hydrogen-based propulsion technologies for passenger ferries, with the aim to draft the strategies that can be adopted to reach that goal. An overview of the current state-of-the-art of hydrogen-based fuel passenger ships is presented: the EcoDesign Strategy Wheel (a tool to helps embed sustainability into any innovation and consider life-cycle impacts of the product) has been chosen to highlight the different approaches adopted by the designers of the existing vessels. The same tool has then been applied to three reference scenarios developed within the EUfunded project "e-SHyIPS" 1 (Ecosystemic knowledge in Standards for Hydrogen Implementation on Passenger Ship). The outcome is a comparison among the two approaches highlighted during the analysis, which provides design support during the future challenges designers and shipbuilders will be called to face during the design loop phases.