PSI - Issue 17

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

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Procedia Structural Integrity 17 (2019) 894–899

ICSI 2019 The 3rd International Conference on Structural Integrity Numerical analysis of the influence of the last cycle scheme on plasticity induced crack closure D. Camas a *, F. Antunes b , B. Moreno a , A. Gonzalez-Herrera a a Department of Civil and Materials Engineering, University of Malaga, C/Dr. Ortiz Ramos s/n, 29071 Malaga, Spain b Centre for Mechanical Engineering, Materials and Processes, Department of Mechannical Engineering, University of Coimbra, Portugal ICSI 2019 The 3rd International Conference on Structural Integrity Numerical analysis of the influence of the last cycle scheme on plasticity induced crack closure D. Camas a *, F. Antunes b , B. Moreno a , A. Gonzalez-Herrera a a Department of Civil and Materials Engineering, University of Malaga, C/Dr. Ortiz Ramos s/n, 29071 Malaga, Spain b Centre for Mechanical Engineering, Materials and Processes, Department of Mechannical Engineering, University of Coimbra, Portugal Plasticity induced crack closure is considered the main mechanism related to the premature contact of the crack flanks when a crack grows under cyclic loadings. This phenomenon has been studied numerically since the early 70s, when some researchers approached to metal fatigue problems by means of the finite element analysis. The numerical analysis requires the development of a plastic wake. How this plastic wake is developed has influence on the crack closure results and a great impact on the computational cost. When running a finite element analysis, it is not possible to consider all the loading cycles involved in an experimental test. The numerical effort is not acceptable. Therefore, in this work, the crack growth scheme is analyzed. In particular, the influence of the number of loading cycles after releasing the last set of nodes on plasticity induced crack closure results is studied. A CT aluminum specimen has been modelled three-dimensionally and several simulations have been run to evaluate the influence of the loading cycles after releasing the last set of nodes. The numerical analysis is made in terms of crack closure and opening values. Plasticity induced crack closure is considered the main mechanism related to the premature contact of the crack flanks when a crack grows under cyclic loadings. This phenomenon has been studied numerically since the early 70s, when some researchers approached to metal fatigue problems by means of the finite element analysis. The numerical analysis requires the development of a plastic wake. How this plastic wake is developed has influence on the crack closure results and a great impact on the co putational cost. When running a finite element analysis, it is not possible to consider all the loading cycles involved in an experimental test. The nu erical effort is not acceptable. Therefore, in this work, the crack growth scheme is analyzed. In particular, the influence of the number of loading cycles after releasing the last set of nodes on plasticity induced crack closure results is studied. A CT aluminum specimen has been modelled three-dimensionally and several simulations have been run to evaluate the influence of the loading cycles after releasing the last set of nodes. The numerical analysis is made in terms of crack closure and opening values. 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: Finite elmeent analysis; plasticity induced crack closure; crack growth scheme; plastic wake. Keywords: Finite elmeent analysis; plasticity induced crack closure; crack growth scheme; plastic wake.

1. Introduction 1. Introduction

Crack closure phenomenon was introduced by Elber in the early 70s (Elber (1970), Elber (1971)). The fracture surface crack flanks interact decreasing the stress intensity around the crack tip. As a consequence, an increase in the fatigue life of the component takes place. Under cyclic loading conditions, the crack grows leaving behind a plastic Crack closure phenomenon was introduced by Elber in the early 70s (Elber (1970), Elber (1971)). The fracture surface crack flanks interact decreasing the stress intensity around the crack tip. As a consequence, an increase in the fatigue life of the component takes place. Under cyclic loading conditions, the crack grows leaving behind a plastic

* Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . E-mail address: dcp@uma.es * Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . E-mail address: dcp@uma.es

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.2019.08.119