PSI - Issue 57

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ScienceDirect

Procedia Structural Integrity 57 (2024) 307–315 Structural Integrity Procedia 00 (2023) 000–000 Structural Integrity Procedia 00 (2023) 000–000

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© 2024 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 Fatigue Design 2023 organizers © 2023 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 scientific committee of the Fatigue Design 2023 organizers. Keywords: FEA; LEFM; Fatigue Crack Growth; welds Abstract Volvo CE currently uses the e ff ective notch stress method for assessing fatigue life in welded structures. For large structures such as frames, a sub modelling technique with a very fine mesh is necessary using millions of DOF. Stress tensors from unit load cases, estimated with FEA, are combined with time history loading from Multi Body Simulations of the complete machine operating on customer representative digitized test tracks. A critical plane approach (the Modified Wo¨hler Curve Method) is used to estimate the fatigue life. The usage of the e ff ective notch method implies a very time-consuming design process. An LEFM approach for weld roots would be even more time-consuming but would be a more natural approach since the weld root consists of crack like defects. To overcome the drawbacks with the current design process that involves usage of the e ff ective notch method, a hybrid method is defined using pre-calculated geometry factors for di ff erent crack sizes and weld geometries. The geometry factors as a function of crack size, and the weld geometry, are stored in a database. From the unit load cases the structural stress using a coarse mesh in the weld is extracted. Together with the geometry factors, the stress intensity factors may be estimated and used with Paris law to calculate the fatigue life of welds. A comparison between the e ff ective notch method, LEFM and the new hybrid method is carried out for typical fillet welds is presented in this paper. © 2023 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 scientific committee of the Fatigue Design 2023 organizers. Keywords: FEA; LEFM; Fatigue Crack Growth; welds Fatigue Design 2023 (FatDes 2023) A simplified fracture mechanics method for fatigue life analysis of weld roots Magnus Andersson a , Per-Olof Danielsson a a Volvo Construction Equipment, Carl Lihnells va¨g, SE-363 41 Braås, Sweden Abstract Volvo CE currently uses the e ff ective notch stress method for assessing fatigue life in welded structures. For large structures such as frames, a sub modelling technique with a very fine mesh is necessary using millions of DOF. Stress tensors from unit load cases, estimated with FEA, are combined with time history loading from Multi Body Simulations of the complete machine operating on customer representative digitized test tracks. A critical plane approach (the Modified Wo¨hler Curve Method) is used to estimate the fatigue life. The usage of the e ff ective notch method implies a very time-consuming design process. An LEFM approach for weld roots would be even more time-consuming but would be a more natural approach since the weld root consists of crack like defects. To overcome the drawbacks with the current design process that involves usage of the e ff ective notch method, a hybrid method is defined using pre-calculated geometry factors for di ff erent crack sizes and weld geometries. The geometry factors as a function of crack size, and the weld geometry, are stored in a database. From the unit load cases the structural stress using a coarse mesh in the weld is extracted. Together with the geometry factors, the stress intensity factors may be estimated and used with Paris law to calculate the fatigue life of welds. A comparison between the e ff ective notch method, LEFM and the new hybrid method is carried out for typical fillet welds is presented in this paper. Fatigue Design 2023 (FatDes 2023) A simplified fracture mechanics method for fatigue life analysis of weld roots Magnus Andersson a , Per-Olof Danielsson a a Volvo Construction Equipment, Carl Lihnells va¨g, SE-363 41 Braås, Sweden

1. Background and introduction 1. Background and introduction

Construction equipment such as articulated and autonomous haulers, see Fig. 1, operate in high duty applications. The main part of the load carrying structure consists of welded structures and fatigue is a potential failure mode. As several loads often interact both in a positive and negative way time based load signals are used with a multi-axial stress approach in the fatigue design analysis. The load signals come mainly from customer representative test tracks Construction equipment such as articulated and autonomous haulers, see Fig. 1, operate in high duty applications. The main part of the load carrying structure consists of welded structures and fatigue is a potential failure mode. As several loads often interact both in a positive and negative way time based load signals are used with a multi-axial stress approach in the fatigue design analysis. The load signals come mainly from customer representative test tracks

∗ Magnus Andersson. Tel.: + 46-470 54 8180. E-mail address: magnus.k.andersson@volvo.com ∗ Magnus Andersson. Tel.: + 46-470 54 8180. E-mail address: magnus.k.andersson@volvo.com

2452-3216 © 2024 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 Fatigue Design 2023 organizers 10.1016/j.prostr.2024.03.033 2210-7843 © 2023 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 scientific committee of the Fatigue Design 2023 organizers. 2210-7843 © 2023 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 scientific committee of the Fatigue Design 2023 organizers.