PSI - Issue 70

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ScienceDirect

Procedia Structural Integrity 70 (2025) 51–58

Structural Integrity and Interactions of Materials in Civil Engineering Structures (SIIMCES-2025) Analysis of Stress Intensity Factors in Semi-Elliptical and Semi Circular Surface Cracked Plates

Varsha S a , Kothapalli Lalitha Vishnu Kamesh a , Piyush Pratap Singh a, * a Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Chennai, India

Abstract The present work proposes an open-form solution to calculate stress intensity factors (SIFs) from out-of-plane fracture modes (Mode I, II, and III) in structural steel rectangular plates containing surface cracks. These analytical methods are valuable for assessing structural integrity in components such as pressure vessels, bridges, and aircraft fuselages under complex loading. High order meshing techniques within ANSYS enabled finite element method (FEM) simulations that validated the theoretical model. The study analyzes semi-elliptical and semi-circular surface cracks with depth-to-length ratios ≤ 0.5 under arbitrary 2D stress distributions. The employed weight function method evaluates SIFs under non-uniform loading with high predictive accuracy. The plate is assumed to be fully clamped along all edges. Results indicate that SIFs at the center of semi-elliptical cracks are approximately 25% higher than in semi-circular ones, with the opposite trend near the surface. An increase in the a/d ratio leads to higher SIFs, providing important input for damage-tolerant design. The derived expressions offer an efficient alternative to full field FEM simulations in early-stage safety evaluations. © 2025 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 the responsibility of International Conference on Structural Integrity Organizers

Keywords: Stress intensity factor; higher order meshing; semi elliptical cracks; FEM;

1. Introduction Predicting fatigue damage in engineering requires reliable information about both the Stress Intensity Factor (SIF) and principles of fracture mechanics. Theoretical investigations note semi-elliptical and semi-circular cracks as typical surface defects, and they transform into partial oval and round configurations after repetitive loading [1]. The

* Corresponding author. Tel.: 91+ 8804854491 E-mail address: piyushpratap12@gmail.com

2452-3216 © 2025 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 the responsibility of International Conference on Structural Integrity Organizers 10.1016/j.prostr.2025.07.025