PSI - Issue 28

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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ScienceDirect

Procedia Structural Integrity 28 (2020) 253–265

© 2020 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 European Structural Integrity Society (ESIS) ExCo Abstract This paper reports on an experimental study of fatigue crack growth in steel specimens. First, block loading tests (sequences of low and high stress intensity factor ranges Δ ) are discussed. Limited crack growth retardation occurs at transitions from low to high load ranges; significant retardation or crack arrest are observed in high-low transitions. Next, semi-random load spectra are created, processed using a peak-and-valley analysis and further reduced by removing the load ranges below the stress intensity factor threshold Δ �� . Rainflow counting is performed to obtain load profiles consisting of a sequence of blocks with constant Δ . For the semi-random and the (reduced) peak-and-valley spectra no significant load interaction is observed. Pronounced crack growth retardation is observed in an ordered spectrum obtained by rainflow counting. The strong reduction in number of cycles of the (reduced) peak-and-valley spectra allows for exploration of accelerated fatigue testing. Experimental results of fatigue crack propagation are compared to results of calculations using a Python based numerical framework. © 2020 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 European Structural Integrity Society (ESIS) ExCo a Ghent University, Faculty of Engineering and Architecture, Department of Electromechanical, Systems and Metals Engineering, Laboratory Soete, Belgium b SIM vzw, Tech Lane Ghent Science Park / Campus A 48, BE-9052, Zwijnaarde, Belgium Abstract This paper reports on an experimental study of fatigue crack growth in steel specimens. First, block loading tests (sequences of low and high stress intensity factor ranges Δ ) are discussed. Limited crack growth retardation occurs at transitions from low to high load ranges; significant retardation or crack arrest are observed in high-low transitions. Next, semi-random load spectra are created, processed using a peak-and-valley analysis and further reduced by removing the load ranges below the stress intensity factor threshold Δ �� . Rainflow counting is performed to obtain load profiles consisting of a sequence of blocks with constant Δ . For the semi-random and the (reduced) peak-and-valley spectra no significant load interaction is observed. Pronounced crack growth retardation is observed in an ordered spectrum obtained by rainflow counting. The strong reduction in number of cycles of the (reduced) peak-and-valley spectra allows for exploration of accelerated fatigue testing. Experimental results of fatigue crack propagation are compared to results of calculations using a Python based numerical framework. © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY- -N license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo 1st Virtual European Conference on Fracture Evaluation of fatigue crack propagation in steel ESET specimens subjected to variable load spectra Wim De Waele a, *, Sven Trogh a , Steven De Tender a , Nahuel Micone a , Kris Hectors a,b, a Ghent University, Faculty of Engineering and Architecture, Department of Electromechanical, Systems and Metals Engineering, Laboratory Soete, Belgium b SIM vzw, Tech Lane Ghent Science Park / Campus A 48, BE-9052, Zwijnaarde, Belgium 1st Virtual European Conference on Fracture Evaluation of fatigue crack propagation in steel ESET speci ens subjected to variable load spectra Wim De Waele a, *, Sven Trogh a , Steven De Tender a , Nahuel Micone a , Kris Hectors a,b,

Keywords: Fatigue; Crack growth; variable amplitude, load sequence, load interaction Keywords: Fatigue; Crack growth; variable amplitude, load sequence, load interaction

* Corresponding author. E-mail address: Wim.DeWaele@ugent.be * Corresponding author. E-mail address: Wim.DeWaele@ugent.be

2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo 2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo

2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo 10.1016/j.prostr.2020.10.031