Fraunhofer Institute for Structural Durability and System Reliability LBFHow can unmachined "as-built" WAAM surfaces be taken into account in the fatigue strength assessment?
MULTI-FUN - Better understanding of additively manufactured WAAM structures and surfaces
Modern technology makes it possible to implement high-resolution 3D scans of components, which can be used to map the surface topography when evaluating the fatigue strength of additively manufactured metallic structures. Advances in computing power also enable a location-dependent fine meshing in finite element simulations and thus form the basis of a digital twin. By combining both sub-steps, the failure under cyclic loading can now be correlated with the stress distribution on the surface of WAAM-manufactured structures, thus enabling the structural behavior to be better mapped in the fatigue strength assessment.
Demonstrator motorcycle handlebars made of aluminum structures additively manufactured using WAAM and their digital twin for numerical load analysis
Multifunctionality through multi-material design
The EU project "Multi-Fun" aims to realize the integration of multifunctionalities in additively manufactured components and structures using WAAM (Wire Arc Additive Manufacturing) through multi-material design. Seven demonstrators were defined and developed for different applications. To derive relevant input and design data, Fraunhofer LBF analyzes, among other things, the component behavior under cyclic load and determines characteristic values to describe the cyclic material behavior. In addition to analyzing anisotropy, for example, the focus is also on recording and evaluating influences from the surface and material imperfections such as porosity. Using the example of a motorcycle handlebar additively manufactured from the material EN AW-6063 with integrated copper conductor tracks, it is shown how unmachined "as-built" WAAM surfaces can be considered in the fatigue strength assessment.
3D scan provides deep insight into the stress distribution of "as-built" AM surfaces
A 3D scanner was used to generate digital images of the weld surfaces, which serve as the basis for FE load simulations. Stress concentrations in the notch base of weld beads show that the influence of notches on the service life of a "notch-free" designed component dominates and that the failure location can be reliably predicted.
Publications
- Development and fatigue assessment of wire arc additively manufactured hollow structures made of AA6063 as a basis for functional integrated sections applied to a motorcycle handlebar - ScienceDirect
- Deriving Representative Structural Elements for the fatigue approach of Wire Arc Additively Manufactured components - ScienceDirect
Sponsors and partners
EU project (This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 862617 - MULTI-FUN)
Projectpartners:
- Leichtmetall Kompetenzzentrum Ranshofen GmbH
- Voestalpine Metal Forming GmbH Austria
- Deutsches Zentrum für Luft- und Raumfahrt DLR Germany
- Fundacion Bcmaterials - Basque Centre for Materials, Applications ans Nanostructures BMC Spain
- Inocon Technologie GmbH Austria
- Fraunhofer-Gesellschaft Germany
- Lortek S Coop Spain
- Inphotech SP ZOO Poland
- Instituto de Soldadura e Qualidade Portugal
- MIGAL.CO GmbH Germany
- European Federation for Welding Joining and Cutting Belgium
- RHP Technology GmbH Austria
- Cranfield University United Kingdom
- WAAM3D Ltd. United Kingdom
- Aerotecnic Metallic SL Spain
- DAG Engineering GmbH Germany
- Peak Technology GmbH Austria
- Alpex Technologies GmbH Austria
- Ruag Space GmbH Austria
- Aluwag AG Switzerland
- AVL LIST GmbH AVL Austria