PSI - Issue 66

ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2025) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2025) 000–000 Procedia Structural Integrity 66 (2024) 247–255

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

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 responsibility of CP 2024 Organizers 10.1016/j.prostr.2024.11.075 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 responsibility of CP 2024 Organizers 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 responsibility of CP 2024 Organizers * Corresponding author. Tel.: +91-44-2257 4694; Fax: +91-44-2257 4652. E-mail address: raghuprakash@iitm.ac.in © 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 responsibility of CP 2024 Organizers © 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 responsibility of CP 2024 Organizers * Corresponding author. Tel.: +91-44-2257 4694; Fax: +91-44-2257 4652. E-mail address: raghuprakash@iitm.ac.in 8th International Conference on Crack Paths Study of Effective Stress Intensity Factor in 3-2-1 Lozenge Pattern Riveted Joints under Biaxial Loading based on the Maximum Energy Release Rate (MERR) Based Crack Advance Criterion Akash Shit a, , Raghu V Prakash a, * a Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India Abstract Riveted joints are commonly used in metallic structures of aerospace, high-pressure vessels, bridge construction, ship structures; some of these joints undergo bi-axial loading. Fatigue cracks initiate early due to the presence of the stress concentration from these riveted joints and propagate to critical dimensions. The understanding of the stress intensity factor (SIF) for cracks emanating from the riveted joints is essential for structural integrity assessment. Several numerical, experimental investigations have focused on the mixed mode fracture behavior of riveted lap joints under biaxial loading for the cracks emanating from critical locations such as a rivet hole, studies on the bi-axially loaded Lozenge pattern riveted joints are limited. In this work, a plane stress LEFM analysis was conducted to study the effective SIF on the bi-axially loaded, 3-2-1 Lozenge pattern riveted joint, by utilizing a standard cruciform specimen and considering the strap as the element under study. The direction of maximum principal stress and the maximum energy release rate are utilized to predict the initial crack location and subsequent crack propagation. The effect of bi-axial load ratios of 0.25, 0.5, 0.75 and 1, as well as, the effect of crack shadowing at the holes of two consecutive rows on the SIF is examined. The single rivet hole at the end of the Lozenge pattern emerges as the most critical location, with a maximum effective SIF that is 70% higher than other rows. At this hole under equi-biaxial loading conditions, the SIF increases up to a crack length of 40 mm; after that, due to the orientation of the local crack tip, the SIF tends to decrease. However, with a decreasing load ratio, a maximum of 83% reduction in SIF for the initial crack and 78% reduction for higher crack lengths has been found at a bi-axial load ratio of 0.25. In the case of two shadow cracks facing each other, a maximum reduction of 3.16% in the SIF at the primary crack is observed. Keywords: Biaxial loading: Crack shadowing; Lozenge pattern Riveted joint; Maximum energy release rate; Stress intensity factor 8th International Conference on Crack Paths Study of Effective Stress Intensity Factor in 3-2-1 Lozenge Pattern Riveted Joints under Biaxial Loading based on the Maximum Energy Release Rate (MERR) Based Crack Advance Criterion Akash Shit a, , Raghu V Prakash a, * a Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India Abstract Riveted joints are commonly used in metallic structures of aerospace, high-pressure vessels, bridge construction, ship structures; some of these joints undergo bi-axial loading. Fatigue cracks initiate early due to the presence of the stress concentration from these riveted joints and propagate to critical dimensions. The understanding of the stress intensity factor (SIF) for cracks emanating from the riveted joints is essential for structural integrity assessment. Several numerical, experimental investigations have focused on the mixed mode fracture behavior of riveted lap joints under biaxial loading for the cracks emanating from critical locations such as a rivet hole, studies on the bi-axially loaded Lozenge pattern riveted joints are limited. In this work, a plane stress LEFM analysis was conducted to study the effective SIF on the bi-axially loaded, 3-2-1 Lozenge pattern riveted joint, by utilizing a standard cruciform specimen and considering the strap as the element under study. The direction of maximum principal stress and the maximum energy release rate are utilized to predict the initial crack location and subsequent crack propagation. The effect of bi-axial load ratios of 0.25, 0.5, 0.75 and 1, as well as, the effect of crack shadowing at the holes of two consecutive rows on the SIF is examined. The single rivet hole at the end of the Lozenge pattern emerges as the most critical location, with a maximum effective SIF that is 70% higher than other rows. At this hole under equi-biaxial loading conditions, the SIF increases up to a crack length of 40 mm; after that, due to the orientation of the local crack tip, the SIF tends to decrease. However, with a decreasing load ratio, a maximum of 83% reduction in SIF for the initial crack and 78% reduction for higher crack lengths has been found at a bi-axial load ratio of 0.25. In the case of two shadow cracks facing each other, a maximum reduction of 3.16% in the SIF at the primary crack is observed. Keywords: Biaxial loading: Crack shadowing; Lozenge pattern Riveted joint; Maximum energy release rate; Stress intensity factor © 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 responsibility of CP 2024 Organizers