Doctoral project: Seaworthiness assessment of WAAM manufactured marine propellers

In this project, we study the general question: How can the seaworthiness of a marine structure and/or component be assessed, when they are constructed using novel and unproven manufacturing technology? The question is studied using the scientific engineering method Systems Engineering and is carried out in the form of a system analysis of WAAM manufactured ship propellers.

Project information

Project manager
Per Lindström Lussi
Other project members
Govindraj Ramesh Babu, Martin Kroon and Lars Håkansson, Linnaeus University; Isak Andersen, DNV GL, Norway
Participating organizations
Linnaeus University; DNV AS, Norway, BERG Propulsion AB
DNV AS, Norway, DYNAmore Nordic AB, BERG Propulsion AB
1 Nov 2019–1 Nov 2025
Mechanical engineering (Department of Mechanical Engineering, Faculty of Technology)

More about the project

Additive manufacturing (AM) of metal parts is a rapidly developing technology with great promise, largely due to its ability to produce fully dense parts with complex geometry in relatively short production times. Wire Arc AM (WAAM) is one of the commercially most used AM processes for maritime applications. Due to its robotic 6 axis rotation and dimension and size, it employs a high energy wire to fuse layer-by-layer.

Although Copper alloy Ni-Al-Bronze (CU3) base alloys are considered as favorable marine propeller construction material for seagoing vessels, WAAM has two main effects: It introduces a high solidification rate in different passes that also get re-heated by subsequent passes. Therefore, each layer undergoes a complex thermo-mechanical history. It is a well-known fact and very well understood that the ultimate physical properties of weld metal depend upon an intricate relationship between several contributing factors (P Lindström 2017), see figure 1.

figure 1
Figure 1. The relation between various variables and the physical properties of weld metal.

This study will address the effect of the thermo-mechanical history on WAAM manufactured marine propellers’ seaworthiness, where seaworthiness is the traditional marine community phrasing for the land based industries’ Fitness For Service (FFS).

The project is part of the research in the Welding Mechanics Laboratory (WML) research group.