PSI - Issue 42

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

ScienceDirect

Procedia Structural Integrity 42 (2022) 1137–1144 Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 0 ( 0 9) 000–000

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

© 2022 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 scientific committee of the 23 European Conference on Fracture – ECF23 Abstract The paper deals with the numerical analysis of damage and fracture mechanisms in steel sheets. Newly developed H-specimens are taken from thin sheets and are tested under di ff erent biaxial loading conditions. Results of numerical simulations of a series of biaxial experiments are presented showing also the e ff ect of non-proportional loading paths on inelastic deformation behavior and on damage processes. In this context, an anisotropic continuum damage model is presented based on yield and damage conditions as well as evolution laws for plastic and damage strain rates. Di ff erent stress-state-dependent branches of the damage criteria are taken into account corresponding to various damage and failure processes on the micro-scale depending on the stress triaxiality and the Lode parameter. Experiments with the biaxially loaded H-specimen have been performed. Results for proportional and corre sponding non-proportional loading histories are discussed. During the experiments strain fields in critical regions of the specimens are analyzed by digital image correlation (DIC) technique. Numerical simulations of the experiments have been performed and nu merical results are compared with experimental data. Furthermore, based on the numerical analysis evolution of stress variables is examined and stress distributions in critical specimens areas are detected allowing prediction of stress-state-dependent damage and fracture mechanisms. The numerical results also demonstrate the e ffi ciency of the experimental program and the new specimens geometries covering stress states in the shear-tension regime as well as the e ff ect of the loading histories on inelastic deformation and damage behavior in steel sheets. c 2020 The Authors. Published by Elsevier B.V. is is an open access article under the CC BY- C-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) r-review unde responsibility of 23 European Conference on Fracture – ECF23 . Keywords: Ductile metals; Steel sheets; Biaxial experiments; Numerical simulation; Non-proportional loading 23 European Conference on Fracture – ECF23 Nu erical analysis of da age and fracture in steel sheets undergoing non-proportional loading paths Michael Bru¨nig a, ∗ , Moritz Zistl a , Ste ff en Gerke a a Institute for Mechanics and Structural Analysis, University of the Bundeswehr Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany Abstract The paper deals with the numerical analysis of damage and fracture mechanisms in steel sheets. Newly developed H-specimens are taken from thin sheets and are tested under di ff erent biaxial loading conditions. Results of numerical simulations of a series of biaxial experiments are presented showing also the e ff ect of non-proportional loading paths on inelastic deformation behavior and on damage processes. In this context, an anisotropic continuum damage model is presented based on yield and damage conditions as well as evolution laws for plastic and damage strain rates. Di ff erent stress-state-dependent branches of the damage criteria are taken into account corresponding to various damage and failure processes on the micro-scale depending on the stress triaxiality and the Lode parameter. Experiments with the biaxially loaded H-specimen have been performed. Results for proportional and corre sponding non-proportional loading histories are discussed. During the experiments strain fields in critical regions of the specimens are analyzed by digital image correlation (DIC) technique. Numerical simulations of the experiments have been performed and nu merical results are compared with experimental data. Furthermore, based on the numerical analysis evolution of stress variables is examined and stress distributions in critical specimens areas are detected allowing prediction of stress-state-dependent damage and fracture mechanisms. The numerical results also demonstrate the e ffi ciency of the experimental program and the new specimens geometries covering stress states in the shear-tension regime as well as the e ff ect of the loading histories on inelastic deformation and damage behavior in steel sheets. 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 23 European Conference on Fracture – ECF23 . Keywords: Ductile metals; Steel sheets; Biaxial experiments; Numerical simulation; Non-proportional loading 23 European Conference on Fracture – ECF23 Numerical analysis of damage and fracture in steel sheets undergoing non-proportional loading paths Michael Bru¨nig a, ∗ , Moritz Zistl a , Ste ff en Gerke a a Institute for Mechanics and Structural Analysis, University of the Bundeswehr Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany

1. Introduction 1. Introduction

Demands on reduction in energy consumption as well as improvement in safety, in lifetime and in cost e ffi ciency of engineering products have led to various research activities to produce high quality metals. The main request is to enhance material strengths in order to reduce localization of inelastic deformations and to avoid damage and fracture of structural elements under di ff erent loading scenarios. Thus, development of material models as well as Demands on reduction in energy consumption as well as improvement in safety, in lifetime and in cost e ffi ciency of engineering products have led to various research activities to produce high quality metals. The main request is to enhance material strengths in order to reduce localization of inelastic deformations and to avoid damage and fracture of structural elements under di ff erent loading scenarios. Thus, development of material models as well as

2452-3216 © 2022 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 scientific committee of the 23 European Conference on Fracture – ECF23 10.1016/j.prostr.2022.12.145 ∗ Corresponding author. Tel.: + 49-89-60043415 ; fax: + 49-89-60044549. E-mail address: michael.bruenig@unibw.de 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 u der re ponsibility of 23 European Conference on Fracture – ECF23 . ∗ Corresponding author. Tel.: + 49-89-60043415 ; fax: + 49-89-60044549. E-mail address: michael.bruenig@unibw.de 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 23 European Conference on Fracture – ECF23 .