PSI - Issue 60

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect StructuralIntegrity Procedia 00 (2023) 000 – 000 ScienceDirect StructuralIntegrity Procedia 00 (2023) 000 – 000

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Procedia Structural Integrity 60 (2024) 177–184

© 2024 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 ICONS 2023 Organizers © 2024 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-reviewunder responsibility of the ICONS 2023 Organizers Keywords: Damage tolerance, stiffened panel, stress intensity factor, fatigue crack growth; Abstract Ever since the introduction of damage tolerance requirements in the aviation regulations, efforts continue to be made to prevent catastrophic failures due to damages present in the structure. It has also been realized that damage detection is the weakest link in the whole process of damage tolerance design to maintain continued airworthiness. The major components of the aircraft structure consist of both integral and riveted panels of sheets and stringers which are employed in fuselage skin panels, spar webs and stiffeners. In spite of all precautions, cracks or damages may arise in many of these primary struct ural members. These cracks cause stiffness degradation and reduce the total load-carrying capacity of the structure. In this paper, the damage tolerance behaviour of fuselage crown panel both integral and riveted stiffened panel configurations of Aluminium alloy 2024-T351 are studied using finite element based tools using crack growth analysis methods. The crack growth behaviour of both integral and riveted stiff ened panels of aircraft fuselage having same geometrical configuration and subjected to uniformly distributed tensile loads is investigated. For this, a metallic stiffened panel with eight stringers, representative of crown panel of a transport aircraft fuselage is analysed with a centre skin crack propagating through the stringers. Stress intensity factors and fatigue crack propagation rates at the progressive crack tip of both types of the stiffened panels are computed by using Modified Virtual Crack Closure Integral (MVCCI) method. The stiffened panels fatigue crack growth rate was computed by using Paris law under constant amplitude fatigue loads. The analysis results show that integral stiffened panel causes higher stress intensity factor and less load bearing capability than riveted stiffened panel which has better damage tolerant capability in comparison to the integrally stiffened panel. © 2024 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-reviewunder responsibility of the ICONS 2023 Organizers Keywords: Damage tolerance, stiffened panel, stress intensity factor, fatigue crack growth; Abstract Ever since the introduction of damage tolerance requirements in the aviation regulations, efforts continue to be made to prevent catastrophic failures due to damages present in the structure. It has also been realized that damage detection is the weakest link in the whole process of damage tolerance design to maintain continued airworthiness. The major components of the aircraft structure consist of both integral and riveted panels of sheets and stringers which are employed in fuselage skin panels, spar webs and stiffeners. In spite of all precautions, cracks or damages may arise in many of these primary struct ural members. These cracks cause stiffness degradation and reduce the total load-carrying capacity of the structure. In this paper, the damage tolerance behaviour of fuselage crown panel both integral and riveted stiffened panel configurations of Aluminium alloy 2024-T351 are studied using finite element based tools using crack growth analysis methods. The crack growth behaviour of both integral and riveted stiff ened panels of aircraft fuselage having same geometrical configuration and subjected to uniformly distributed tensile loads is investigated. For this, a metallic stiffened panel with eight stringers, representative of crown panel of a transport aircraft fuselage is analysed with a centre skin crack propagating through the stringers. Stress intensity factors and fatigue crack propagation rates at the progressive crack tip of both types of the stiffened panels are computed by using Modified Virtual Crack Closure Integral (MVCCI) method. The stiffened panels fatigue crack growth rate was computed by using Paris law under constant amplitude fatigue loads. The analysis results show that integral stiffened panel causes higher stress intensity factor and less load bearing capability than riveted stiffened panel which has better damage tolerant capability in comparison to the integrally stiffened panel. Third International Conference on Structural Integrity 2023 (ICONS 2023) Damage Tolerance Behaviour of Stiffened Crown Panel of a Transport Aircraft Fuselage Third International Conference on Structural Integrity 2023 (ICONS 2023) Damage Tolerance Behaviour of Stiffened Crown Panel of a Transport Aircraft Fuselage M Mohan Kumar a ∗ , Srinivas Prabhu G a , Chetan Reddy a a Structural Integrity Division, CSIR-National Aerospace Laboratories, Bangalore-560017 M Mohan Kumar a ∗ , Srinivas Prabhu G a , Chetan Reddy a a Structural Integrity Division, CSIR-National Aerospace Laboratories, Bangalore-560017

* Corresponding author. Tel.: ++91-(0)80- 2508 6325; fax: +91-(0)80- 2508 6310 , E-mail address: mmk@nal.res.in

∗ This

2452-3216© 2024 The Authors. Published by ELSEVIER B.V. * Corresponding author. Tel.: ++91-(0)80- 2508 6325; fax: +91-(0)80- 2508 6310 , E-mail address: mmk@nal.res.in 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 ICONS 2023 Organizers 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 ICONS 2023 Organizers 2452-3216© 2024 The Authors. Published by ELSEVIER B.V.

∗ This

2452-3216 © 2024 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 ICONS 2023 Organizers 10.1016/j.prostr.2024.05.039