PSI - Issue 28

Available online at www.sciencedirect.com Available online at www.sciencedirect.com Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 28 (2020) 146–154 Structural Integrity Procedia 00 (2020) 000–000 Structural Integrity Procedia 00 (2020) 000–000

www.elsevier.com / locate / procedia www.elsevier.com / locate / procedia

© 2020 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 European Structural Integrity Society (ESIS) ExCo Abstract Together with the development of numerical tools for stress-strain analysis, approaches to deal with fracture mechanics problems have been the object of continuous improvement. For linear-elastic fracture mechanics problems, the determination of Stress Intensity Factors (SIF) is available as a post-processing possibility in most commercial finite element software packages such as Ansys and Abaqus, allowing the users to perform straightforward assessments of cracked mechanical parts or structures. However, available techniques for SIF determination in post-processing of these commercial solutions are almost limited to the so-called displacement extrapolation and J-integral techniques. In the present work, the implementation of the J-integral technique is revised considering a new finite element software, labeled as Omicron. Furthermore, a more recent technique, the modified Virtual Crack Closure Technique (mVCCT) is also implemented and evaluated. For results assessment, finite element models were built in Omicron and SIFs were determined considering the J-integral and mVCCT approaches. From this study, it is concluded that the mVCCT implementation is simpler than the J-integral and it allows to determine accurately SIFs. Nevertheless, this technique is not straightly available in the current versions of the commercial packages for finite element modeling, which require separate post-processing for SIF determination. c 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY- C-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Pe r-r ie under responsibility of the European Structural Integrity Society (ESIS) ExCo. Keywords: Finite element method; Fracture mechanics; Stress intensity factor; J-integral; Modified virtual crack closure technique. 1st Virtual European Conference on Fracture Numerical determination of stress intensity factors: J-integral and modified virtual crack closure technique Carlos D.S. Souto a, ∗ , Se´rgio M.O. Tavares a , Jose´ A.F.O. Correia a , Ab´ılio M.P. De Jesus a a Faculty of Engineering of the University of Porto, Porto, Portugal Abstract Together with the development of numerical tools for stress-strain analysis, approaches to deal with fracture mechanics problems have been the object of continuous improvement. For linear-elastic fracture mechanics problems, the determination of Stress Intensity Factors (SIF) is available as a post-processing possibility in most commercial finite element software packages such as Ansys and Abaqus, allowing the users to perform straightforward assessments of cracked mechanical parts or structures. However, available techniques for SIF determination in post-processing of these commercial solutions are almost limited to the so-called displacement extrapolation and J-integral techniques. In the present work, the implementation of the J-integral technique is revised considering a new finite element software, labeled as Omicron. Furthermore, a more recent technique, the modified Virtual Crack Closure Technique (mVCCT) is also implemented and evaluated. For results assessment, finite element models were built in Omicron and SIFs were deter ined considering the J-integral and mVCCT approaches. From this study, it is concluded that the mVCCT implementation is simpler than the J-integral and it allows to determine accurately SIFs. Nevertheless, this technique is not straightly available in the current versions of the commercial packages for finite element modeling, which require separate post-processing for SIF determination. c 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo. Keywords: Finite element method; Fracture mechanics; Stress intensity factor; J-integral; Modified virtual crack closure technique. 1st Virtual European Conference on Fracture Numerical determination of stress intensity factors: J-integral and modified virtual crack closure technique Carlos D.S. Souto a, ∗ , Se´rgio M.O. Tavares a , Jose´ A.F.O. Correia a , Ab´ılio M.P. De Jesus a a Faculty of Engineering of the University of Porto, Porto, Portugal

1. Introduction 1. Introduction

Computational fracture mechanics has progressed significantly in last decades, with diverse new methods for the stress evaluation, allowing to evaluate complex fracture mechanics problems with relative low computational cost (Ingra ff ea and de Borst, 2017). For metallic structures, as well as aluminium aircraft structures, typical approaches are based on linear-elastic fracture mechanics to evaluate the fatigue crack propagation in order to compute the fatigue life of these structures under di ff erent loading and boundary conditions (Tavares and de Castro, 2019). The greatest computational cost in these analyses is the characterization of stress and displacements fields, required for the deter- Computational fracture mechanics has progressed significantly in last decades, with diverse new methods for the stress evaluation, allowing to evaluate complex fracture mechanics problems with relative low computational cost (Ingra ff ea and de Borst, 2017). For metallic structures, as well as aluminium aircraft structures, typical approaches are based on linear-elastic fracture mechanics to evaluate the fatigue crack propagation in order to compute the fatigue life of these structures under di ff erent loading and boundary conditions (Tavares and de Castro, 2019). The greatest computational cost in these analyses is the characterization of stress and displacements fields, required for the deter-

2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo 10.1016/j.prostr.2020.10.019 ∗ Corresponding author. Tel.: + 351-925-712-227. E-mail address: csouto@fe.up.pt 2210-7843 c 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo. ∗ Corresponding author. Tel.: + 351-925-712-227. E-mail address: csouto@fe.up.pt 2210-7843 c 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo.