PSI - Issue 18

Available online at www.sciencedirect.com 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 ScienceDirect

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ScienceDirect

Procedia Structural Integrity 18 (2019) 663–670

25th International Conference on Fracture and Structural Integrity Influence of critical plane definition on fatigue lifetime estimation under variable amplitude nonproportional multiaxial loading. Matus Margetin a *, Miloslav Kepka b a Slovak University of Technology, Faculty of Mechanical Engineering, Institute of applied mechanics and mechatronics, Námestie slobody 17, 812 31 Bratislava, Slovak republic b Regional Technological Institute, Research Center of the Faculty of Mechanical Engineering, University of West Bohemia, Univerzitni 2732/8, 30614 Pilsen, Czech Republic Abstract In real operation, most of load bearing parts are commonly loaded with multiaxial variable amplitude loading. Fatigue lifetime estimation of such a component consists of multiple tasks. One of the most important problem to solve is how to handle multiaxiality of loading signal. Nowadays, the most commonly used way is use of multiaxial fatigue criterion based on critical plane theory. These criterions are based on assumption that fatigue lifetime of a component is determined by combination of shear and normal stresses (strains) in particular plane (critical plane). The definition of such a plane varies depending on different used criterions. While fatigue lifetime of component loaded with proportional loading signal can be estimated based on damage accumulated in critical plane, during the fatigue lifetime estimation under variable amplitude nonproportional loading the damage in noncritical plane has to be considered as well. This, however, leads to inaccuracy of the final results as multiaxial criterions often incorrectly calculate damage in noncritical plane. The aim of this paper is to discuss the influence of critical plane definition on fatigue lifetime estimation under variable amplitude nonproportional multiaxial loading. The results from fatigue lifetime estimations of component loaded by modeled signal using multiple different multiaxial criterions (with different critical plane definition) are presented and critically discussed. 25th International Conference on Fracture and Structural Integrity Influence of critical plane definition on fatigue lifetime estimation under variable amplitude nonproportional multiaxial loading. Matus Margetin a *, Miloslav Kepka b a Slovak University of Technology, Faculty of Mechanical Engineering, Institute of applied mechanics and mechatronics, Námestie slobody 17, 812 31 Bratislava, Slovak republic b Regional Technological Institute, Research Center of the Faculty of Mechanical Engineering, University of West Bohemia, Univerzitni 2732/8, 30614 Pilsen, Czech Republic Abstract In real operation, most of load bearing parts are commonly l aded with ultiaxial variable amplitude loading. Fatig e lifetime estimation of such a component consists of ultiple tasks. One of th most important problem to s lve is how to handle multiaxiality of loading sig al. Nowadays, the ost commonly sed way is use f multiaxial fatigue criterion based on critical pl e theory. These criterio s are based on assumption that fatigue lifetime of a component is determined by combi ation of shear and normal stresses (strains) in particular lane (critical plane). The definiti n of such pl e varies depending on different used criterions. While fatigue lifetime of component loaded with proportional loading signal can be estimated based on damage accumulated in critical plane, during the fatigu lifetime estimation under variable amplitude onproportional lo ding the damage i noncritical plane has to be considered as well. This, however, leads to inaccuracy of the final results as multiaxial criterions often incorrectly calculate damage in noncritical plane. The aim of this paper is to discuss the infl ence of critical plane d finition on fatigue lifetime estimation un er variable amplitude nonproportional multiaxial loading. The results from fatigue lifetime estimations of component loaded by model signal using multiple different multiaxial criterions (with different critical plane definition) are presented and critically discussed.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

Keywords: multiaxial; fatigue; critical plane; nonproportional loading Keywords: multiaxial; fatigue; critical plane; nonproportional loading

* Corresponding author. Tel.: +421 903 294 884. E-mail address: matus.margetin@stuba.sk * Correspon ing author. Tel.: +421 903 294 884. E-mail address: matus.margetin@stuba.sk

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2019.08.214