PSI - Issue 81

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ScienceDirect

Procedia Structural Integrity 81 (2026) 47–53

© 2026 The Authors. Copy from the contract: 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 DMDP 2025 organizers Keywords: surface semi-elliptical cracks; surface crack interaction; simulation modeling; interaction factors; regression equations 1. Introduction The development of new machines and structures with high performance characteristics, as well as the need to reduce their material consumption while simultaneously increasing strength and durability, is a relevant but challenging task. Under service loading, cracks, in particularly surface cracks, may initiate in regions of structural stress concentrators. Under subsequent cyclic loading, these cracks can propagate and reach critical sizes (Brighenti and Carpinteri, 2013; Pang et al., 2017; Pidgurskyi et al., 2025, Yasniy et al., 2016, Yasniy et al., 2017). The process of simultaneous growth of multiple surface cracks (Fig. 1) can generally be divided into four phases as it is shown in the study by Patel et al., 2010: • the isolated growth stage of individual cracks, during which they do not interact with each other (Stage 1); • the stage of mutual interaction (s ≤ max{0.5 a ₁ ; 0.5 a ₂ }), during which the cracks begin to interact as they approach each other up to the point of contact (Stage 2); • the crack coalescence stage, during which the cracks merge into a single crack, whose contour transforms from a saddle shaped form into a semi-elliptical one (Stage 3); Abstract The scientific and engineering problem of interaction between two identical coplanar surface cracks under tensile loading is investigated. Based on the analysis of available experimental data and finite element simulations, a simulation model of the interaction between two surface semi elliptical cracks that gradually approach each other under cyclic loading is developed. The results of the simulation modeling allowed the dominant factors influencing the variation of the stress intensity factor during the interaction of two surface cracks to be identified. Statistical mathematical models are proposed to describe the variation of the stress intensity factors at characteristic points of identical surface semi elliptical cracks in the region of their maximum interaction (inner points), as well as at the deepest points of the surface cracks. Regression relationships were obtained to evaluate the crack interaction factors as functions of the crack geometric parameters. The proposed statistical model is promising for predicting the structural integrity and fatigue life of components, taking into account the stage of surface crack interaction. VIII International Conference “In - service Damage of Materials: Diagnostics and Prediction“ (DMDP 2025) Model for Evaluating Stress Intensity Factor K ₁ under Interaction of Identical Surface Cracks Ivan Pidgurskyi a, * a Ternopil Ivan Puluj National Technical University, 56 Ruska St., Ternopil 46001, Ukraine

* Corresponding author. Tel.: +38(066) 837 27 31. E-mail address: ipidhurskyy@gmail.com

2452-3216 © 2026 The Authors. Copy from the contract: 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 DMDP 2025 organizers 10.1016/j.prostr.2026.03.009