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A novel approach for enhancing the fatigue lifetime of the components processed by additive manufacturing technologies

Amin S. Azar (SINTEF Industry, Oslo, Norway)
Magnus Reiersen (University of Oslo, Oslo, Norway)
Even W. Hovig (NTNU, Trondheim, Norway)
Mohammed M’hamdi (SINTEF Industri, Oslo, Norway)
Spyros Diplas (SINTEF Industri, Oslo, Norway)
Mikkel M. Pedersen (Aarhus University, School of Engineering, Aarhus, Denmark)

Rapid Prototyping Journal

ISSN: 1355-2546

Article publication date: 27 January 2021

Issue publication date: 2 March 2021

211

Abstract

Purpose

This study aims to introduce a novel approach in form of a comprehensive software suite to help understanding and optimizing the build orientation toward maximizing the fatigue lifetime of complex geometries. The objective is to find an optimized build orientation under a given in-service loading state, which brings on smoother surfaces in stressed regions, mitigated roughness-induced stress concentration and deferred crack initiation stage. The solution addresses scenarios that no post-build surface treatment can be applied.

Design/methodology/approach

To account for the surface topography, the staircase induced surface roughness is registered as a function of build angle using the white light interferometry characterization, based on which the stress concentration factor (kt) is calculated. Thereafter, the developed module in “Fatlab toolbox” is used to find the optimum build angle, considering the integrated surface orientations and stress analysis under a given loading condition.

Findings

Surface topography creates local stress concentrations upon loading, directly influencing the fatigue lifetime. It is a well-established fact that the conditions of the staircase geometry and surface roughness affect the magnitude of the stress concentration upon loading, which is influenced by the build orientation of the component. The proposed solution suggests the best build orientation that mitigates staircase-related surface roughness.

Originality/value

The suggested numerical approach assists the designers with positioning of the part on the build plate to minimize the build orientation-induced surface roughness and improve the as-built fatigue lifetime of the component.

Keywords

Acknowledgements

The authors would like to acknowledge the members of the HydrosFond board for supporting the PALMA project in the framework for the development of printable Al alloys for powder bed additive manufacturing. The authors also appreciate the contributions of Martin Fleissner Sunding for developing the white light interferometry characterization method.

Data availability: The relevant data to this work is open-source, and it can be accessed through the fatiguetoolbox.org website.

Citation

S. Azar, A., Reiersen, M., Hovig, E.W., M’hamdi, M., Diplas, S. and Pedersen, M.M. (2021), "A novel approach for enhancing the fatigue lifetime of the components processed by additive manufacturing technologies", Rapid Prototyping Journal, Vol. 27 No. 2, pp. 256-267. https://doi.org/10.1108/RPJ-02-2020-0030

Publisher

:

Emerald Publishing Limited

Copyright © 2020, Emerald Publishing Limited

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