AddMan project

The project, funded under Horizon 2020 and Clean Sky 2: Innovative Re-Design and Validation of Complex Airframe Structural Components Formed by Additive Manufacturing for Weight and Cost Reduction, aims at enabling aerospace industry to efficiently redesign and manufacture optimal system components for reduced weight and costs while meeting the prevailing stress and fatigue requirements and regulations by using additive manufacturing technology. The partners involved are:

• Linköping University including following divisions:
  • Engineering Materials
  • Solid Mechanics
  • Machine Design
• The Manufacturing Technology Centre
• Saab AB

Highlights

Major milestone achieved: 3D printed of a complex load lift fitting

One of the major milestones in AddMan has been achieved in March 2020, the successful manufacturing of the demonstrator load lift fitting supplied to Saab by the MTC to be used in the next generation of cargo doors and aircraft structures. The part was successfully manufactured within the tolerance requirements specified for the component.

New paper published in collaboration between LiU, Saab and the MTC

A paper based on the AddMan results with the title "Improved fatigue strength of additively manufactured Ti6Al4V by surface post processing" has been published in International Journal of Fatigue in January 2020. The paper covers investigation of fatigue behaviour of additive manufactured Ti64 alloy produced by EBM and SLM with as-build and five different surface conditions. More information can found here: https://doi.org/10.1016/j.ijfatigue.2020.105497.

Technical and review project meeting, September 2018

The 3^rd project meeting, which was both a technical and a review meeting, was held on 24-25 of September at LiU and Saab, Linköping, Sweden. The meetings went very well and were very productive. The meeting and the project progress were briefly summarized by all participants at the end of Day 2, it was a common view that the goals of the meetings were fulfilled and that the project is going as planned. No serious issues, that would change the project objectives and the work plan, were identified.

Trinitas Topology Optimization Tutorial Document

A tutorial showing how to use Trinitas, which is an integrated graphical stand-alone environment for Conceptual design, Optimization and General finite element analysis, for TO is pusblished in Open Access at LiU, for more information see this link: urn:nbn:se:liu:diva-151903. For more information about Trinitas visit http://www.solid.iei.liu.se/Offered_services/Trinitas/.

Post processing development

WP2 focuses on characterisation of Ti-6Al-4V specimens produced by SLM and EBM, including determination of general mechanical property data, residual stress measurement and fatigue testing. In addition, different techniques for the optimisation of fatigue performance by cost effective surface post processing are also being investigated. One of the main achievements of WP2 is optimisation and development of five post processing methods aimed to optimise surface roughness and feature retention. This work has been done at the MTC. The post processing methods investigated were:

1. Abrasive finishing (linishing),
2. Abrasive tumbling (centrifugal finishing),
3. Laser polishing,
4. Shot peening and
5. Laser shock peening.

To ensure the post processing methods chosen would achieve good results, the MTC teams have developed the process parameters for each method, for both the EBM, and SLM. This work involved the use of several Design of Experiments (DOE’s), the results of which highlighted the most suitable combination of process parameters the available technology was capable of.

Developments in Topology Optimization - a new report published

This document gives an account of some of the work done so far on topology optimization (TO) in the AddMan project. As well as the mathematical formulations and implementations details, short discussions are presented on some of the nuances of the different formulations and how they should be used efficiently.

Topology Optimization for Additive Manufacturing Considering Stress and Anisotropy - MSc thesis published

In this thesis a procedure is developed to optimize the AM build orientation considering anisotropic elastic material properties. A transversely isotropic material model is used to represent the in-plane and out-of-plane characteristics of AM produced parts. Two additional design variables are added to the TO formulation in order to control the orientation of the material using a coordinate transformation. Sensitivity analysis for the material direction variables is conducted for compliance as well as maximum von-Mises stress using a -norm stress aggregation function. The thesis is published in Open Access at LiU via this link: urn:nbn:se:liu:diva-141609.