PSI - Issue 39

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000 il l li t . i i t. tr t r l I t rit r i ( )

www.elsevier.com/locate/procedia . l i r. /l t / r i

ScienceDirect

Procedia Structural Integrity 39 (2022) 98–103

7th International Conference on Crack Paths Damage tolerance of a hybrid lower wing bonded stiffened panel with a Fiber Metal Laminate skin J.C. Ehrström a *, J. Laye a , E. Nizery a , N. Bayona-Carrillo b m a a N a b

a Constellium C-TEC, 725 rue Aristide Bergès, BP 27, 38341 Voreppe Cedex, France b Constellium Usine d’Issoire, ZI des Listes, BP42, 63502 Issoire Cedex, France t lli - , i ti , , , b t lli i ’I i , I i t , , I i , a

Abstract b

© 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 CP 2021 – Guest Editors Crack growth from an initial defect is monitored using Thermal Surface Analysis and visual inspection. The propagation life between the chosen detection event and the residual strength test is 137580 cycles. This detection event is a broken stringer; it occurs after the crack in the FML skin has reached a 39 mm length. The residual strength exceeds the required limit load. The total life from crack initiation at the notch to the crack length reached before the residual strength test is 220000 cycles. Combining the stress allowable increment and density reduction, the test justifies a 25% weight saving potential versus a lower wing in 2024 T351, with 45000 flight cycles inspection intervals and 90000 flight cycles Design Service Goal. © 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) t t t ti t t i l t t t t i l . i t ti t i t i ; it t t i t i l t . i l t t t i li it l . t t l li i iti ti t t t t t l t t i l t t t t i l . i i t t ll l i t it ti , t t t j ti i i t i t ti l l i i , it li t l i ti i t l li t l i i l. © 2021 The Autho . li . . is is an open access article under the CC BY-NC-N li tt :// ti . /li / / . Fiber Metal Laminates (FML) represent a highly damage tolerant option for lower wing skins that can be included in an advanced high performance metallic wing box. The purpose of the present study is to assess the damage tolerance behavior of a panel made of FML with 0.8 mm 2024 T3 sheet and bonded stringers. A 5-stringer test panel, 800 mm wide, is tested at R=0.1 at a maximum stress of 135 MPa. This stress conservatively represents a spectrum with a sustained flight stress (1 g stress) of 90 MPa corresponding to a 20% increase versus a conventional 2024 T351 lower wing allowable stress. i i t t i l i i t lli i . t t t i t t t l i l it . t t i . t i t t l, i , i t t t . t i t . i t ti l t t it t i li t t t i t i ti l l i ll l t . i t l i t t i l t l t ti l t i iti l t i it i l l i i l i ti . ti li

Peer-review under responsibility of CP 2021 – Guest Editors Keywords: Fatigue crack growth; Wing panel; Fiber Metal Laminate Peer-review under responsibility of CP 2021 – Guest E it : ti r r t ; i l; i r t l i t

* Corresponding author. Tel.: +33.476578150 E-mail address: jean-christophe.ehrstrom@constellium.com i t r. l.: . - il : j - ri t . r tr t lli . rr

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 CP 2021 – Guest Editors 2452-3216 © 2021 The Authors. Published by ELSEVIER B.V. i i rti l r t - - li ( tt :// r ti . r /li / - - / . ) r-r i r r i ilit f t it r

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 CP 2021 – Guest Editors 10.1016/j.prostr.2022.03.077

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