PSI - Issue 24

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ScienceDirect

Procedia Structural Integrity 24 (2019) 764–774 Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 00 (2019) 000–000

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AIAS 2019 International Conference on Stress Analysis Bending fatigue behaviour of 17-4 PH gears produced via selective laser melting AIAS 2019 International Conference on Stress Analysis Bending fatigue behaviour of 17-4 PH gears produced via selective laser melting

Luca Bonaiti a, ∗ , Franco Concli b , Carlo Gorla a , Francesco Rosa a a Department of Mechanical Engineering, Politecnico di Milano, via La Masa 1, 20157 Milano, Italy b Faculty of Science and Technology, Free University of Bozen-Bolzano, piazza Università, 1, 39100 Bolzano, Italy Luca Bonaiti a, ∗ , Franco Concli b , Carlo Gorla a , Francesco Rosa a a Department of Mechanical Engineering, Politecnico di Milano, via La Masa 1, 20157 Milano, Italy b Faculty of Science and Technology, Free University of Bozen-Bolzano, piazza Università, 1, 39100 Bolzano, Italy

© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the AIAS2019 organizers Abstract The possibility of producing parts via the addition of material, instead of its removing, given by Additive Manufacturing (AM) processes is changing the way in which parts are designed. However, the design of some mechanical components like gears, for instance, requires specific resistance data that, up to now, are not presented in literature. This paper presents a research project aimed at investigating the bending fatigue properties of 17-4 PH steel applied to gears produced via selective laser melting. Single Tooth bending Fatigue (STF) tests were conducted in order to investigate the S-N curve. Results are presented in terms of tooth root stress calculated according to the ISO standard in order to compare them with data of other materials. In addition, Scanning Electron Microscopy (SEM) of the fractured surfaces has been performed on the failed teeth to investigate failure origin and therefore to find causes of tooth breakage. 2019 The Authors. Published by Elsevier B.V. T is is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) r-review lin : Peer-rev ew und r responsibility of the AIAS2019 organizers. Keywords: 174-PH; selective laser melting; gears; bending fatigue; gearbox design Abstract The possibility of producing parts via the addition of material, instead of its removing, given by Additive Manufacturing (AM) processes is changing the way in which parts are designed. However, the design of some mechanical components like gears, for instance, requires specific resistance data that, up to now, are not presented in literature. This paper presents a research project aimed at investigating the bending fatigue properties of 17-4 PH steel applied to gears produced via selective laser melting. Single Tooth bending Fatigue (STF) tests were conducted in order to investigate the S-N curve. Results are presented in terms of tooth root stress calculated according to the ISO standard in order to compare them with data of other materials. In addition, Scanning Electron Microscopy (SEM) of the fractured surfaces has been performed on the failed teeth to investigate failure origin and therefore to find causes of tooth breakage. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review line: Peer-review under responsibility of the AIAS2019 organizers. Keywords: 174-PH; selective laser melting; gears; bending fatigue; gearbox design

Nomenclature Nomenclature

b Facewidth d en diameter of the outer point of single pair tooth contact F t Tangential force h ∗ aP Addendum coe ffi cient of the basic rack profile h Fe Bending moment arm h ∗ f P Dedendum coe ffi cient of the basic rack profile m n Normal module q S Notch parameter b Facewidth d en diameter of the outer point of single pair tooth contact F t Tangential force h ∗ aP Addendum coe ffi cient of the basic rack profile h Fe Bending moment arm h ∗ f P Dedendum coe ffi cient of the basic rack profile m n Normal module q S Notch parameter

∗ Corresponding author. Tel.: + 39 02-2399-8290; fax: + 39-02-2399-8263. E-mail address: luca.bonaiti@polimi.it ∗ Corresponding author. Tel.: + 39 02-2399-8290; fax: + 39-02-2399-8263. E-mail address: luca.bonaiti@polimi.it

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the AIAS2019 organizers 10.1016/j.prostr.2020.02.068 2210-7843 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review line: Peer-review under responsibility of the AIAS2019 organizers. 2210-7843 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review line: Peer-review under responsibility of the AIAS2019 organizers.