PSI - Issue 35

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2021) 000 – 000 Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 35 (2022) 98–105

© 2021 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 IWPDF 2021 Chair, Tuncay Yalçinkaya Abstract In this study, the effect of the block overload duration on the two-dimensional crack propagation life was experimentally investigated. In the experiments, different sizes of overload cycles were applied on Compact Tension (CT) specimens machined from rolled Al-7075-T6 plates. The experiments showed that if applied block overload cycles are extended, the crack growth accelerates, because the overload cycles dominate the crack growth. In the short cycle block overload case, crack propagates slower than the case of single overload due to the plasticity-induced effect in the crack tip. After the tests, crack growth life was calculated using some models in the literature, and the results were compared with the experiments. Close results to the experiments were obtained with Wheeler model and its modifications. © 2021 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) 1. Introduction Many engineering structures operate under variable amplitude loading. For example, an aircraft in the air or ships in the ocean run under the most complex case of variable amplitude loading, which is also named as random loading. Studies in the literature, which consider the load interaction effects, first discussed the single overloading case to investigate the crack growth behavior under variable amplitude loading. Due to the sudden increase in loading, a larger plastic zone is generated at the crack tip than in previous load cycles. This difference in plastic zone dimensions affects the residual compressive stress levels at the crack tip and the corresponding crack propagation rate after the load 2nd International Workshop on Plasticity, Damage and Fracture of Engineering Materials The Effect of Overload Block Size on Fatigue Crack Growth Life M.Faruk Yaren a , A. O. Ayhan a *, Sedat Iric a a Department of Mechanical Engineering, Sakarya University, 54050 Sakarya, Turkey Peer-review under responsibility of IWPDF 2021 Chair, Tuncay Yalçinkaya Keywords: "crack growth, variable amplitude loading, block loading, retardation"

* Corresponding author. E-mail address: ayhan@sakarya.edu.tr

2452-3216 © 2021 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 IWPDF 2021 Chair, Tuncay Yalçinkaya

2452-3216 © 2021 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 IWPDF 2021 Chair, Tuncay Yal ç inkaya 10.1016/j.prostr.2021.12.053