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New Approach for Characterizing Cyclic Crack Growth by Loading, Unloading, and Reloading Testing

Hausmann A, Gehrmann B, Hafez Haghighat M, Höppel HW, Neumeier S (2026)

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Publication Type: Conference contribution

Publication year: 2026

Publisher: Springer Science and Business Media Deutschland GmbH

Pages Range: 733-742

Conference Proceedings Title: Minerals, Metals and Materials Series

Event location: Pittsburgh, USA

ISBN: 9783032351753

DOI: 10.1007/978-3-032-35176-0_40

Abstract

A novel testing approach for cyclic crack-growthcyclic crack-growth characterization is presented, enabling faster data generation and evaluation of crack propagation behavior at both room and elevated temperatures. This is particularly relevant for superalloysSuperalloy used in critical high-temperature applications such as turbine engines, where fatigue cracks can lead to catastrophic failure. Due to their complex microstructuresMicrostructures, superalloysSuperalloy are especially sensitive to crack initiation and propagation, requiring accurate and efficient fatigue life prediction. Conventional fatigue crack-growth tests using compact tension or corner crack specimens under constant load amplitude are often time-consuming. However, particularly during alloy development and optimization, when rapid screening of material properties is necessary, faster methods would be useful. The new method presented here employs single-edge notched bend specimens following ASTM E1820, with cyclic loading, unloading, and reloading at a constant stress rate. The maximum stress increases incrementally with each cycle until fracture. At each maximum loading reversal point, the differential elastic modulus (ED) is determined. Progressive crack growth reduces the load-bearing cross section and further decreases ED. The stress dependence of the stiffness in the undamaged state ED0 must be considered. The ED/ED0 ratio allows estimation of crack length and cross-sectional area reduction over time. For validation of this new approach, Alloy 718Alloy 718 was tested, stress-intensity factors were calculated according to ASTM E1820, and cyclic crack-growthcyclic crack-growth rates (da/dN) were plotted against the stress-intensity range (ΔKI), producing classic fatigue crack-growth curves. The very good agreement with literature data demonstrates the strong potential of this method for accelerated material screening.

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How to cite

APA:

Hausmann, A., Gehrmann, B., Hafez Haghighat, M., Höppel, H.W., & Neumeier, S. (2026). New Approach for Characterizing Cyclic Crack Growth by Loading, Unloading, and Reloading Testing. In Eric A. Ott, Chantal Sudbrack, Andrew Wessman, Joel Andersson, Zhongnan Bi, Ian Dempster, Martin Detrois, Michael Fahrmann, Michael Kirka, Jonah Klemm-Toole, Daisuke Nagahama, Jérémy Rame, Kevin Severs, Kinga Unocic (Eds.), Minerals, Metals and Materials Series (pp. 733-742). Pittsburgh, USA: Springer Science and Business Media Deutschland GmbH.

MLA:

Hausmann, Andreas, et al. "New Approach for Characterizing Cyclic Crack Growth by Loading, Unloading, and Reloading Testing." Proceedings of the 11th International Symposium on Superalloy 718 and Derivatives, ISS 2026, Pittsburgh, USA Ed. Eric A. Ott, Chantal Sudbrack, Andrew Wessman, Joel Andersson, Zhongnan Bi, Ian Dempster, Martin Detrois, Michael Fahrmann, Michael Kirka, Jonah Klemm-Toole, Daisuke Nagahama, Jérémy Rame, Kevin Severs, Kinga Unocic, Springer Science and Business Media Deutschland GmbH, 2026. 733-742.

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