PSI - Issue 35

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ScienceDirect

Procedia Structural Integrity 35 (2022) 150–158 Structural Integrity Procedia 00 (2021) 000–000 Structural Integrity Procedia 00 (2021) 000–000

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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 Structural components are subjected to variable thermomechanical loads during use. These loads can lead to fatigue failure therefore it is important to detect potential weak points in the structure already during early stages of the R&D process. Reliable results of the stress-strain response are of crucial importance during the structural analyses. In this paper, a metallic pipe bend is subjected to a variable thermomechanical load and its structural response is investigated. The loads reach beyond the yield stress of the material, therefore an elastoplastic stress-strain response is observed. Prandtl operator approach, implemented into the finite element analysis, is used to simulate the response of the pipe bend. The approach enables fast and accurate structural simulations using the material parameters gained from uniaxial low-cycle fatigue testing at few test temperatures. The approach considers a cyclic elastoplastic material behaviour with multilinear kinematic hardening at variable temperatures. Comparison with the commonly used Besseling model shows a comparable stress-strain path simulation, but ensures a 30 % shorter computational time. Fatigue lifetime estimation di ff ers for 4 % at the critical control point for the analysed thermomechanical load history. 2021 The Authors. Published by Elsevier B.V. T is is an open access article under the CC BY-NC-ND license (http: // creativec mmons.org / licenses / by-nc-nd / 4.0 / ) r-review unde responsibility of IWPDF 2021 Chair, Tuncay Yalc¸inkaya. Keywords: finite element method; thermomechanical loading; Prandtl operator; plasticity; fatigue; pipe bend 2nd International Workshop on Plasticity, Damage and Fracture of Engineering Materials Elastoplastic response of a pipe bend using Prandtl operator approach in a finite element analysis Domen Sˇ eruga a , Jernej Klemenc a , Simon Oman a , Marko Nagode a, ∗ a University of Ljubljana, Faculty of Mechanical Engineering, Ljubljana, Slovenia Abstract Structural components are subjected to variable thermomechanical loads during use. These loads can lead to fatigue failure therefore it is important to detect potential weak points in the structure already during early stages of the R&D process. Reliable results of the stress-strain response are of crucial importance during the structural analyses. In this paper, a metallic pipe bend is subjected to a variable thermomechanical load and its structural response is investigated. The loads reach beyond the yield stress of the material, therefore an elastoplastic stress-strain response is observed. Prandtl operator approach, implemented into the finite element analysis, is used to simulate the response of the pipe bend. The approach enables fast and accurate structural simulations using the material parameters gained from uniaxial low-cycle fatigue testing at few test temperatures. The approach considers a cyclic elastoplastic material behaviour with multilinear kinematic hardening at variable temperatures. Comparison with the commonly used Besseling model shows a comparable stress-strain path simulation, but ensures a 30 % shorter computational time. Fatigue lifetime estimation di ff ers for 4 % at the critical control point for the analysed thermomechanical load history. © 2021 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 IWPDF 2021 Chair, Tuncay Yalc¸inkaya. Keywords: finite element method; thermomechanical loading; Prandtl operator; plasticity; fatigue; pipe bend 2nd International Workshop on Plasticity, Damage and Fracture of Engineering Materials Elastoplastic response of a pipe bend using Prandtl operator approach in a finite element analysis Domen Sˇ eruga a , Jernej Klemenc a , Simon Oman a , Marko Nagode a, ∗ a University of Ljubljana, Faculty of Mechanical Engineering, Ljubljana, Slovenia

1. Introduction 1. Introduction

Pipe bends are integral parts of fluid and gas transport systems in power plants, oil refineries, automotive, nautical and aerospace industries, water supply or sewage systems (Roy et al. (2021); Yoon et al. (2017); Sˇ eruga et al. (2014); Nagode et al. (2012); Yu et al. (2021); Yazdekhasti et al. (2017)). In recent years, pipes and pipe bends have also become indispensable structural members of lightweight structures (Shim et al. (2016); Ancellotti et al. (2019)). Regardless of the application, variable thermal and mechanical loads act on the pipe bends during their lifetime due to the operating conditions or environmental e ff ects. Moreover, as pipe bends absorb higher mechanical loads as compared to straight pipes, they usually represent critical components in the pipeline networks (Roy et al. (2021)). The study of the elastoplastic behaviour of the pipe bends in the pipeline network during the typical operation or Pipe bends are integral parts of fluid and gas transport systems in power plants, oil refineries, automotive, nautical and aerospace industries, water supply or sewage systems (Roy et al. (2021); Yoon et al. (2017); Sˇ eruga et al. (2014); Nagode et al. (2012); Yu et al. (2021); Yazdekhasti et al. (2017)). In recent years, pipes and pipe bends have also become indispensable structural members of lightweight structures (Shim et al. (2016); Ancellotti et al. (2019)). Regardless of the application, variable thermal and mechanical loads act on the pipe bends during their lifetime due to the operating conditions or environmental e ff ects. Moreover, as pipe bends absorb higher mechanical loads as compared to straight pipes, they usually represent critical components in the pipeline networks (Roy et al. (2021)). The study of the elastoplastic behaviour of the pipe bends in the pipeline network during the typical operation or

∗ Corresponding author. Tel.: + 386-1-4771-507, Fax: + 386-1-4214-074 E-mail address: marko.nagode@fs.uni-lj.si ∗ Corresponding author. Tel.: + 386-1-4771-507, Fax: + 386-1-4214-074 E-mail address: marko.nagode@fs.uni-lj.si

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.2021.12.059 2210-7843 © 2021 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 IWPDF 2021 hair, Tuncay Yalc¸inkaya. 2210-7843 © 2021 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 IWPDF 2021 Chair, Tuncay Yalc¸inkaya.