PSI - Issue 19

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 19 (2019) 442–451

Fatigue Design 2019 Fatigue Assessment of Additively Manufactured Metallic Structures Using Local Approaches Based on Finite-Element Simulations Kai Schnabel * , Jörg Baumgartner, Benjamin Möller Fraunhofer Institute for Structural Durability ans System Reliability LBF, 64289 Darmstadt, Germany Fatigue Design 2019 Fatigue Assessment of Additively Manufactured Metallic Structures Using Local Approaches Based on Finite-Element Simulations Kai Schnabel * , Jörg Baumgartner, Benjamin Möller Fraunhofer Institute for Structural Durability ans System Reliability LBF, 64289 Darmstadt, Germany The fatigue behavior of additively manufactured components with geometrical notches, represented by notched specimens, manufactured by Laser Powder Bed Fusion (LPBF), is investigated. A numerical comparison between the nominal and received ‘ as built ’ geometry is performed in order to characterize the difference between both states and to be able to assess its influence on the fatigue strength. Selected fatigue assessment concepts are applied for additively manufactured structures to examine the reliability of these concepts and their suitability for an industrial application. Finally, the calculated results are compared with experimental fatigue tests. For an improvement of accuracy of the estimation, an assessment concept based on structural elements is proposed. The fatig e behavior of ad itively manufactured components with geo trical notches, represented by notched specimens, manufactured by Laser Powder Bed Fusion (LPBF), is investigated. A numerical comparison between the nominal a d r ceived ‘ as built ’ geometry is performed in order to characterize the difference between both states a d to be able to assess its influe ce on the fatigue strength. Selected fatigue assessment concepts are applied for additively manufactur str ctures to examine the reliability of these concepts and their suitability for an industrial application. Finally, the calculated results are ompared with ex erimental fatigue tests. For an improvement of accuracy of the estimation, an assessment concept based on structural elements is proposed. Abstract Abstract

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers.

Keywords: Fatigue Assessment; Laser Powder Bed Fusion; Finite-Element-Method; Notched Specimen; Structural Elements Keywords: Fatigue Assessment; Laser Powder Bed Fusion; Finite-Element-Method; Notched Specimen; Structural Elements

1. Introduction 1. Introduction

Additive manufacturing (AM) technologies for metallic materials are gaining importance in different industrial applications like the automotive or the aviation sector. Subsequently, also the fatigue strength and its assessments has to be considered. The Laser Powder Bed Fusion (LBPF) process is widely used because of its possibility to realize complex and branched structures. It is applied to components that need an ideal material utilization and an optimized shape in terms of force transmission. In this manufacturing process, a given CAD geometry is first reconstructed into single slices which are arranged normal to the building direction. In this first step, the basis for the mechanical and fatigue properties of the component is set, because the arrangement of the component in relation to the building direction determines not only the microstructure but also the design and realization of the mandatory support structure. Additive manufacturing (AM) technologies for metallic materials are gaining importance in different industrial applications like the automotive or the aviation sector. Subsequently, also the fatigue strength and its assessments has to be considered. The Laser Powder Bed Fusion (LBPF) process is widely used because of its possibility to realize complex and branched structures. It is applied to components that need an ideal material utilization and an optimized shape in terms of force transmission. In this manufacturing process, a given CAD geometry is first reconstructed into single slices which are arranged normal to the building direction. In this first step, the basis for the mechanical and fatigue properties of the component is set, because the arrangement of the component in relation to the building direction determines not only the microstructure but also the design and realization of the mandatory support structure.

* Corresponding author. Tel.: +49 6151 705-451. E-mail address : kai.schnabel@lbf.fraunhofer.de * Corresponding uthor. Tel.: +49 6151 705-451. E-mail address : kai.schnabel@lbf.fraunhofer.de

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers.

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. 10.1016/j.prostr.2019.12.048