PSI - Issue 17

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000

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ScienceDirect

Procedia Structural Integrity 17 (2019) 878–885

ICSI 2019 The 3rd International Conference on Structural Integrity SHM TB30, Numerical Study of an Aircraft Structural Condition Martins, T. 1* , Infante, V. 1 , Sousa, L. 1 , Antunes, P.J. 2 , Moura, A.M. 2 , Serrano, B. 3 ICSI 2019 The 3rd International Conference on Structural Integrity SHM TB30, Numerical Study of an Aircraft Structural Condition Martins, T. 1* , Infante, V. 1 , Sousa, L. 1 , Antunes, P.J. 2 , Moura, A.M. 2 , Serrano, B. 3 1 LAETA, IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal 2 Critical Materials SA, Portugal 3 CIDIUM, CIAFA, Academia da Força Aérea, Pero Pinheiro, Portugal 1 LAETA, IDMEC, Instituto Supe ior Técnico, niversidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisb a, Portugal 2 Critical Materials SA, Portugal 3 CIDIUM, CIAFA, Academia da Força Aérea, Pero Pinheiro, Portugal The purpose of this paper is the estimation of the Fatigue Lifetime of the Portuguese Air Force's Epsilon TB-30 aircraft, by strain analysis on critical components of the aircraft. The experimental studies and knowledge of aircraft loads was used to reverse engineer a suitable Finite Element Model of the structure, from which the stress fields in previously identified structural hotspots were retrieved. Cumulative damage on the structure is calculated for reference loading spectra using the Palgrem-Miner rule and suitable fatigue criteria. The Stress Intensity Factors at the critical component's notched geometry were estimated using two different approaches: the Finite Element and Extended Finite Element Methods from ABAQUS © . Crack propagation was then modelled using several laws (Paris, Walker, NASGRO, Forman). A comparison between the two numerical methods and the results of the several propagation laws are presented. Parameters for the various equations for AA 2024-T3 are obtained through the fitting of prior experimental data. Lastly, it was suggested new scheduling of maintenance activities to adjust the manufacturer's spectrum results to the loading conditions of the aircraft. The purp se of this paper is the estimat on of the Fatigue Lifetime of the Portuguese Air Force's Epsilon TB-30 aircraft, by strain analysis on critical components of th aircraft. The experimental studies and knowledge of aircraft loads was sed to reverse engine r a suitable Finite Element Model of the structure, from which the stress fields in previously identified structural hotspots were retrieved. Cumulative damage on the structure is calculated for reference loading spectra using the Palgrem-Miner rule and suitable fatigue criteria. The Stress Intensity Factors at the critical component's notched geometry were estimated using tw different approaches: the Finite Elem nt and Extended Finite Element Methods from ABAQUS © . Cra k propagatio was th n modelled using several laws (P ris, Walk r, NASGRO, Forman). A comparison between the two numerical metho s and t e r sults of the several propag tion laws are presented. Paramet rs for the various equatio s for AA 2024-T3 are obtained through the fitting of prior xperimental data. Lastly, it was suggested new scheduling of maintenance activities to adjust the manufacturer's spectrum results to the loading conditions of the aircraft. Abstract Abstract

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers.

Keywords: Fatigue, Crack propagation modelling, XFEM, Structural Health Monitoring Keywords: Fatigue, Crack propagation modelling, XFEM, Structural Health Monitoring

1. Introduction 1. Introduction

The Epsilon TB 30 fleet is used by the Portuguese Air Force (PoAF) for pilot training. These are tandem, two-seater, low wing aircraft with retractable landing gear and were acquired by PoAF in 1987. The Epsilon TB 30 fleet is used by the Portuguese Air Force (PoAF) for pilot training. These are tandem, two-seater, low wing aircraft with retractable landing gear and were acquired by PoAF in 1987.

* Corresponding author. Tel.: +351 965148361. E-mail address: tiago.r.martins@tecnico.ulisboa.pt * Corresponding author. Tel.: +351 965148361. E-mail address: tiago.r.martins@tecnico.ulisboa.pt

The aircraft was designed with no specific requirements for useful life. For this reason, the manufacturer performed real scale tests on these planes at the Aeronautics Test Centre of Toulouse (CEAT) using load spectra acquired from The aircraft was designed with no specific requirements for useful life. For this reason, the manufacturer performed real scale tests on these planes at the Aeronautics Test Centre of Toulouse (CEAT) using load spectra acquired from

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers.

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 10.1016/j.prostr.2019.08.117