PSI - Issue 35

ScienceDirect 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 Available online at www.sciencedirect.com Procedia Structural Integrity 35 (2022) 82–90

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© 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 IWPDF 2021 Chair, Tuncay Yalçinkaya Abstract Although the uniaxial tensile test gives information about the formability limits of the material, different formability tests are required to obtain the stretch formability limit of the material. Hole expansion test is a process performed to obtain the formability limit considering the stretching conditions of a sheet with a hole. For automotive industry, this forming limit has a crucial role in the reliability of the engineering parts exposed to the several stretching modes. In the present study, the hole expansion tests of twinning induced plasticity (TWIP940) and transformation induced plasticity (TRIP590) steel sheets were simulated using finite element method. Implicit Msc. Marc software in conjunction with the Hypela2 user subroutine file, was used for the numeric solutions. The plastic work-based failure criterion was incorporated into the subroutine and the homogeneous fourth-order polynomial-based yield function (HomPol4), was considered to define the bound of the yield loci. Hole expansion ratio and the failure strain predicted from simulations were compared with the experimental results to assess the capability of the HomPol4 criterion. It was seen that the numerical results were in good agreement with the experimental results for both steel sheets. Moreover, failure stroke values were predicted using the failure criterion. Stroke value was successfully predicted for the TWIP940 steel, which does not exhibit a significant amount of strain localization. On the other hand, a difference between the numerical and experimental results was observed for TRIP590 steel sheet. Abstract Although the uniaxial tensile test gives information about the formability limits of the material, different formability tests are required to obtain the stretch formability limit of the material. Hole expansion test is a process performed to obtain the formability limit considering the stretching conditions of a sheet with a hole. For automotive industry, this forming limit has a crucial role in the reliability of the engineering parts exposed to the several stretching modes. In the present study, the hole expansion tests of twinning induced plasticity (TWIP940) and transfor ation induced plasticity (TRIP590) steel sheets were simulated using finite element method. Implicit Msc. Marc software in conjunction with the Hypela2 user subroutine file, was used for the numeric solutions. The plastic work-based failure criterion was incorporated into the subroutine and the homogeneous fourth-order polynomial-based yield function (HomPol4), was considered to define the bound of the yield loci. Hole expansion ratio and the failure strain predicted from simulations ere compared with the experimental results to assess the capability of the HomPol4 criterion. It was seen that the numerical results were in good agreement with the experimental results for both steel sheets. Moreover, failure stroke values were predicted using the failure criterion. Stroke value was successfully predicted for the TWIP940 steel, which does not exhibit a significant amount of strain localization. On the other hand, a difference between the numerical and experimental results was observed for TRIP590 steel sheet. Keywords: Hole expansion; failure prediction; plastic work; finite element method; anisotropic yield function 1. Int oduction Recently, to reduce car weight and CO 2 emissions, several alternative materials have been used in automotive industry. Am g them, advanced high strength steels (AHSS) stand out because they not only decrease the car weight 2nd International Workshop on Plasticity, Damage and Fracture of Engineering Materials Failure Prediction in Hole Expansion Test Using Plastic Work Criterion Toros Arda Akşen a , Bora Şener b , Emre Esener c , Mehmet Fırat a * 2nd International Workshop on Plasticity, Damage and Fracture of Engineering Materials Failure Prediction in Hole Expansion Test Using Plastic Wo k Criterion Toros Arda Akşen a , Bora Şener b , Emre Esener c , Mehmet Fırat a * a Department of Mechanical Engineering, University of Sakarya, Sakarya 54050, Turkey b Department of Mechanical Engineering, Yildiz Technical University, Istanbul 34349, Turkey c Department of Mechanical Engineering, Bilec ik Şeyh Edebali University , Bilecik 11230, Turkey a Department of Mechanical Engineering, University of Sakarya, Sakarya 54050, Turkey b Department of Mechanical Engineering, Yildiz Technical University, Istanbul 34349, Turkey c Department of Mechanical Engineering, Bilec ik Şeyh Edebali University , Bilecik 11230, Turkey Keywords: Hole expansion; failure prediction; plastic work; finite element method; anisotropic yield function 1. Introduction Recently, to reduce car weight and CO 2 emissions, several alternative materials have been used in automotive industry. Among them, advanced high strength steels (AHSS) stand out because they not only decrease the car weight

* Corresponding author. Tel.: +0-264-295-5850. E-mail address: firat@sakarya.edu.tr

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 IWPDF 2021 Chair, Tuncay Yal ç inkaya 10.1016/j.prostr.2021.12.051 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 IWPDF 2021 Chair, Tuncay Yalçinkaya 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 IWPDF 2021 Chair, Tuncay Yalçinkaya * Corresponding author. Tel.: +0-264-295-5850. E-mail address: firat@sakarya.edu.tr