Naval Group, a European leader in naval defense, and Centrale Nantes, a French engineering institution, have printed the first demonstrator of hollow propeller blades using metal additive manufacturing (AM) as part of the European H2020 project "Realisation and Demonstration of Advanced Material Solutions for Sustainable and Efficient Ships" (RAMSSES).
Funded by the European Commission, this collaborative program aims to reduce the environmental impact of ships. Centrale Nantes and Naval Group are taking the lead within this project on the production of innovative propeller demonstrators to improve the operational capabilities of ships.
In order to improve vessel propulsion, Centrale Nantes and Naval Group are using AM to design large parts (propellers of 6 m in diameter), which could not be produced thus far using traditional manufacturing technologies. Implementing the Wire Arc for Additive Manufacturing (WAAM) process allows for the printing of large parts and paves the way for the production of propellers with more complex geometry.
Industrial Gains
The one-third scale hollow blade demonstrator, representative of a container ship propeller, was printed in stainless steel in under 100 hours, weighing in at about 300 kg. "The teams' technical proficiency means that weight gains of over 40% will be achievable compared to conventional processes," said a spokesperson.
Operational Gains
Sirehna, a Centrale Nantes spin-off and subsidiary of Naval Group, is piloting the blade design in order to improve propeller energy efficiency and reduce their environmental impact. Sirehna's work has led to an overall optimization of blades in terms of efficiency and endurance, as well as a significant reduction in radiated noise and vibrations. Reducing the environmental footprint linked to propulsion, as demonstrated in the H2020 RAMSSES project case study, is a challenge for all types of vessels, and particularly for large container ships.
Naval Group and Sirehna have been able to utilize the technical resources and extensive knowledge offered by Centrale Nantes. The school's expertise in trajectory generation and AM is needed to produce the blade. This long-standing co-operation, which took on a formal footing in 2016 with the creation of a Joint Laboratory of Marine Technology (JLMT), feeds through to control over the entire digital chain from design to mechanical dimensioning and hydrodynamics to manufacturing, and will lead to the production of a complete propeller.
Naval Group's Patrice Vinot, Propeller Package Manager for the RAMSSES project, underlines the challenge of such a manufacturing process, "Although AM is increasingly present in industry, the programming and design of complex parts, such as propeller blades for ships, represent a considerable challenge for our teams and partners. The potential of the process revealed by this new case study means that we now anticipate unparalleled performance for the propellers of tomorrow. Taking part in projects such as RAMSSES, and coordinating our network of academic and industrial partners, will allow us to bring 3-D printing into shipyards for the long term."
Professor Jean-Yves Hascoët, head of the Rapid Manufacturing Platform at Centrale Nantes and international expert in AM, said, "AM has been developed over the last 35 years on the Rapid Manufacturing Platform. All these years of research come to fruition through a project like RAMSSES, which represents a real transfer of our technologies into an industrial environment."
RAMSSES is a 48-month collaborative program involving 21 work packages and 37 partners from 12 countries, and marked by the presence of the main shipyards (Damen, Meyer Werft, STX France, Naval Group, etc.) and European maritime research laboratories (including TNO in the Netherlands and the RISE Research Institutes of Sweden). The goal is to perform experimental campaigns and demonstrate that new advanced material solutions in ship design can reduce their environmental footprint.
Created in 2016, the JLMT is a joint laboratory in industry and research with the general objective to jointly mobilize academic and industrial skills of Centrale Nantes, Nantes University and Naval Group in order to result in qualified innovation for Naval Group's industrial applications in the field of naval construction.
Founded in 1919, Centrale Nantes' undergraduate, master's and doctoral programs are based on the latest scientific and technological developments and best management practices. At Centrale Nantes, research and training are organized into three key areas for growth and innovation: manufacturing, energy transition and healthcare.
For more information contact:
Centrale Nantes
www.ec-nantes.fr
Naval Group
www.naval-group.com