PSI - Issue 42

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

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Procedia Structural Integrity 42 (2022) 66–71

© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 © 2022 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 23 European Conference on Fracture - ECF23 Keywords: Fatigue; elastomer; metal forming Abstract Cold forging h s high potential as a sustainabl pr duction technology. With net- hape production, only the material needed for the produced part is used. By not heating up the workpie e, en rgy consumpti n is also low. How v r, this leads t high forming ce a d consequently cri ical stress in e tools. An curate prediction of tool ife is therefor necessary; both to find measur for its increase and to plan tool changes with minimal achine downtime. Currently there is litt e da a about he fatigue properties of cold forgi g tool materials. Exi ting tests to det mine t is data strongly simplify the tools ’ stress state to a uniaxial load. Therefore, a new fatigue test is pre ented in this paper, which incorpo ates the actua load conditions of cyclically swell ng inner pressures. For this purpos , a high-streng h lastomer i s used as pressure m dium. Its low compressibility and high lasticity allow for cyclic t sti g with pressures up t at least 2000 MPa. This load causes wear on the lastomer, s it is pr s ed nto the gap tween the punch used to apply the load and the fatigue specimen. Ther f re, the gap between punch and fatigue spe im n should be as low as po sible to ensure stabl test c nditions. Within th scope of the researc , f tigue failure already occurred one p cimen. This shows that the compression of elastomers is able to generate very high loads comparable to the cold forging of steel. © 2022 The Authors. Published by Elsevier B.V. This is an ope acces article under the CC BY-N -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) P er-review under re ponsibili y of 23 European Conference on Fracture - ECF23 Keywords: Fatigue; elastomer; metal forming 23 European Conference on Fracture - ECF23 Use of elastomers as pressure media for fatigue testing of cold forging tools Martin Killmann a *, Marion Merklein a a Institute of Manufacturing Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 13, 91058 Erlangen, Germany Abstract Cold forging has high potential as a sustainable production technology. With net-shape production, only the material needed for the produced part is used. By not heating up the workpiece, energy consumption is also low. However, this leads to high forming forces and consequently critical stresses in the tools. An accurate prediction of tool life is therefore necessary; both to find measures for its increase and to plan tool changes with minimal machine downtime. Currently there is little data about the fatigue properties of cold forging tool materials. Existing tests to determine this data strongly simplify the tools ’ stress state to a uniaxial load. Therefore, a new fatigue test is presented in this paper, which incorporates the actual load conditions of cyclically swelling inner pressures. For this purpose, a high-strength elastomer i s used as pressure medium. Its low compressibility and high elasticity allow for cyclic testing with pressures up to at least 2000 MPa. This load causes wear on the elastomer, as it is pressed into the gap between the punch used to apply the load and the fatigue specimen. Therefore, the gap between punch and fatigue specimen should be as low as possible to ensure stable test conditions. Within the scope of the research, fatigue failure already occurred in one specimen. This shows that the compression of elastomers is able to generate very high loads comparable to the cold forging of steel. 23 European Conference on Fracture - ECF23 Use of elastomers as pressure media for fatigue testing of cold forging tools Martin Killmann a *, Marion Merklein a a Institute of Manufacturing Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 13, 91058 Erlangen, Germany

* Corresponding author. Tel.: +49 9131 85 27174; fax: +49 9131 85 27141. E-mail address: martin.killmann@fau.de * Correspon ing author. Te .: +49 9131 85 27174; fax: +49 9131 85 27141. E-mail address: martin.killmann@fau.de

2452-3216 © 2020 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 23 European Conference on Fracture - ECF23 2452-3216 © 2020 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 23 European Conference on Fracture - ECF23

2452-3216 © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 10.1016/j.prostr.2022.12.007