PSI - Issue 68

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Procedia Structural Integrity 68 (2025) 1287–1293 Procedia Structural Integrity 00 (2024) 000–000 Procedia Structural Integrity 00 (2024) 000–000

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European Conference on Fracture 2024 Stress state dependent phase field modeling of ductile fracture I. Yucel a,b , C. Erdogan a , T. Yalc¸inkaya a, ∗ a Department of Aerospace Engineering, Middle East Technical University, Ankara 06800, Tu¨rkiye b Repkon Machine and Tool Industry and Trade Inc., Istanbul 34980, Tu¨rkiye Abstract The simulation of ductile fracture is commonly performed with uncoupled damage modeling techniques using the finite element method. In this approach, damage evolution is defined by a failure criterion, and the failure itself is simulated by deleting elements. The local nature of this modeling process results in significant mesh dependency in both crack initiation and propagation phases for certain geometries. Non-local methods have been proposed as a solution to such issues in failure simulations through the introduction of a length scale. The phase-field fracture method is used in this work to address mesh dependency problems in the ductile failure simulations of Inconel 718. The Johnson-Cook and modified Mohr-Coulomb damage criteria for Inconel 718 are utilized in both the uncoupled approach and phase field fracture model. Finite element simulations are performed with varying element sizes and orientations in the crack propagation region, and the results are compared with the experimental observations. Uncoupled ductile failure simulations are performed with Abaqus / Explicit solver while the phase field fracture simulations utilize Abaqus / Standard, and the models are implemented through user subroutines for both methods. Results indicate that the phase field fracture method can be an e ffi cient solution to the mesh dependency problem for ductile fracture simulations. © 2025 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 ECF24 organizers. Keywords: Ductile Failure; Phase Field Fracture; Finite Element Method; Non-local Modeling European Conference on Fracture 2024 Stress state dependent phase field modeling of ductile fracture I. Yucel a,b , C. Erdogan a , T. Yalc¸inkaya a, ∗ a Department of Aerospace Engineering, Middle East Technical University, Ankara 06800, Tu¨rkiye b Repkon Machine and Tool Industry and Trade Inc., Istanbul 34980, Tu¨rkiye Abstract The simulation of ductile fracture is commonly performed with uncoupled damage modeling techniques using the finite element method. In this approach, damage evolution is defined by a failure criterion, and the failure itself is simulated by deleting elements. The local nature of this modeling process results in significant mesh dependency in both crack initiation and propagation phases for certain geometries. Non-local methods have been proposed as a solution to such issues in failure simulations through the introduction of a length scale. The phase-field fracture method is used in this work to address mesh dependency problems in the ductile failure simulations of Inconel 718. The Johnson-Cook and modified Mohr-Coulomb damage criteria for Inconel 718 are utilized in both the uncoupled approach and phase field fracture model. Finite element simulations are performed with varying element sizes and orientations in the crack propagation region, and the results are compared with the experimental observations. Uncoupled ductile failure simulations are performed with Abaqus / Explicit solver while the phase field fracture simulations utilize Abaqus / Standard, and the models are implemented through user subroutines for both methods. Results indicate that the phase field fracture method can be an e ffi cient solution to the mesh dependency problem for ductile fracture simulations. © 2025 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 ECF24 organizers. Keywords: Ductile Failure; Phase Field Fracture; Finite Element Method; Non-local Modeling © 2025 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 ECF24 organizers Ductile fracture is known to happen by the nucleation, growth and coalescence of microvoids inside the material that eventually leads to total failure. This mechanism of metallic materials is an important research subject that has been studied extensively for many years. One reason for its significance is that industries such as automotive and avia tion rely on these materials for the safe and e ffi cient operation of their products. Experiments are essential to examine and understand the failure characteristics of ductile materials. On the other hand, numerical simulation methods such as finite element (FE) analyses are extensively used to study the deformation and failure of materials at a reduced cost. Over the years, a wide range of numerical frameworks have been developed that have the ability to predict the damage and fracture characteristics of the materials up to high levels of precision. Ductile fracture modeling using FE analysis with progressive damage evolution results in strain localization in a band whose thickness is determined by the minimum element size, leading to an unphysical response as the mesh is Ductile fracture is known to happen by the nucleation, growth and coalescence of microvoids inside the material that eventually leads to total failure. This mechanism of metallic materials is an important research subject that has been studied extensively for many years. One reason for its significance is that industries such as automotive and avia tion rely on these materials for the safe and e ffi cient operation of their products. Experiments are essential to examine and understand the failure characteristics of ductile materials. On the other hand, numerical simulation methods such as finite element (FE) analyses are extensively used to study the deformation and failure of materials at a reduced cost. Over the years, a wide range of numerical frameworks have been developed that have the ability to predict the damage and fracture characteristics of the materials up to high levels of precision. Ductile fracture modeling using FE analysis with progressive damage evolution results in strain localization in a band whose thickness is determined by the minimum element size, leading to an unphysical response as the mesh is 1. Introduction 1. Introduction

2452-3216 © 2025 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 ECF24 organizers 10.1016/j.prostr.2025.06.200 ∗ Corresponding author. Tel.: + 90-312-210-4258 ; fax: + 90-312-210-4250. E-mail address: yalcinka@metu.edu.tr 2210-7843 © 2025 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 ECF24 organizers. ∗ Corresponding author. Tel.: + 90-312-210-4258 ; fax: + 90-312-210-4250. E-mail address: yalcinka@metu.edu.tr 2210-7843 © 2025 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 ECF24 organizers.