PSI - Issue 54

ScienceDirect Structural Integrity Procedia 00 (2023) 000–000 Structural Integrity Procedia 00 (2023) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

Procedia Structural Integrity 54 (2024) 196–203

© 2023 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 ICSI 2023 organizers whereby the fitting parameter q is related to the slope and the parameter r with the degree of curvature of the fitting curve. The Tiedemann equation showed the best agreement with the measured data for both short and long cracks, thus providing a simple way to determine the length of semi-elliptical fatigue cracks on a surface acquired from potential data. In this work, the propagation of short fatigue cracks emanating from the surface in low alloyed steel is investigated. To get a defined crack initiation site a small notch is prepared using a laser engraving system. The crack length is measured with a DC potential drop method by copper wires laser spot welded onto the surface at a distance of 1 mm below and above the laser notch. To mark the size of the half-elliptical cracks on the fracture surface, overloads were introduced in fixed intervals. The individual cracked area as well as the crack depth and length on the surface were measured using an image analysis program. In this experimental work, besides the Johnson equation, a simple approach based on a function suggested by Tiedemann (2016) was used as described in Eqn. (1). = ( − 1) + ℎ (1) whereby the fitting parameter q is related to the slope and the parameter r with the degree of curvature of the fitting curve. The Tiedemann equation showed the best agreement with the measured data for both short and long cracks, thus providing a simple way to determine the length of semi-elliptical fatigue cracks on a surface acquired from potential data. International Conference on Structural Integrity 2023 (ICSI 2023) Determining the Length of Short Surface Cracks with DC Potential Drop Measurements Naveen Kumar Kanna a *, Jürgen Bär a Universität der Bundeswehr München, Institute of Materials Science Werner-Heisenberg-Weg 39, 85579 Neubiberg, Germany International Conference on Structural Integrity 2023 (ICSI 2023) Determining the Length of Short Surface Cracks with DC Potential Drop Measurements Naveen Kumar Kanna a *, Jürgen Bär a Universität der Bundeswehr München, Institute of Materials Science Werner-Heisenberg-Weg 39, 85579 Neubiberg, Germany The DC Potential drop (DCPD) measurement technique is often used to measure the crack length in fatigue tests. The resolution of this method advances with the crack length. In consequence, the determination of the length of short fatigue cracks is not very precise, especially when the Johnson equation (Johnson (1965)) is used to calculate the crack length from the measured potential drop. Abstract The DC Potential drop (DCPD) measurement technique is often used to measure the crack length in fatigue tests. The resolution of this method advances with the crack length. In consequence, the determination of the length of short fatigue cracks is not very precise, especially when the Johnson equation (Johnson (1965)) is used to calculate the crack length from the measured potential drop. In this work, the propagation of short fatigue cracks emanating from the surface in low alloyed steel is investigated. To get a defined crack initiation site a small notch is prepared using a laser engraving system. The crack length is measured with a DC potential drop method by copper wires laser spot welded onto the surface at a distance of 1 mm below and above the laser notch. To mark the size of the half-elliptical cracks on the fracture surface, overloads were introduced in fixed intervals. The individual cracked area as well as the crack depth and length on the surface were measured using an image analysis program. In this experimental work, besides the Johnson equation, a simple approach based on a function suggested by Tiedemann (2016) was used as described in Eqn. (1). = ( − 1) + ℎ (1) Abstract

* Corresponding author. Tel.: +498960044141; fax: +498960043055. E-mail address: naveen.kanna@unibw.de * Corresponding author. Tel.: +498960044141; fax: +498960043055. E-mail address: naveen.kanna@unibw.de

2452-3216 © 2023 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 ICSI 2023 organizers 10.1016/j.prostr.2024.01.073 2452-3216 © 2023 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 ICSI 2023 organizers 2452-3216 © 2023 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 ICSI 2023 organizers