PSI - Issue 39

ScienceDirect StructuralIntegrity Procedia 00 (2019) 000–000 StructuralIntegrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceD rect Available online at www.sciencedirect.com ScienceDirect

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

Procedia Structural Integrity 39 (2022) 599–607

© 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 CP 2021 – Guest Editors Abstract In the process of the material degradation under cyclic loading is usually distinguishing several stages such as crack initiation, crack growth and final fracture. The local stress stage is changing with the degradation process and especially during the crack growth stage. The convenient approach to predict the total fatigue life is usually based on two different problems: (1) use of a multiaxial criterion to estimate duration of the crack initiation; (2) used of Paris law to estimate the stable crack growth duration. However, during the evaluation of stress state a different crack opening modes can act. This change is clearly observed in the case of pure torsion loading. The propagated torsion crack combines normal and shear crack opening stages. The convenient approaches are not suitable to predict such fatigue behavior of structural elements. This paper is introducing a new approach to estimate the total fatigue life, including the crack initiation and propagation stages, with regards to crack opening mechanisms. The proposed approach is based on the modern model of the full SN curve, damage theory and takes into an account the normal and shear mechanisms of fatigue damage accumulation. The paper contains the result of numerical simulation for VHCF torsion tests prediction. © 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 CP 2021 – Guest Editors Keywords: VHCF; torsion; numerical simulation; damage theory; crack path; fatigue life prediction; crack opening. 1. Introduction In the process of the material fatigue failure is usually distinguished three different stages: (1) crack initiation; (2) crack propagation; (3) final failure. The final failure is usually appearing in the last semi-cycle of loading and do not contribute much to the total fatigue life. The contribution of crack initiation and crack propagation stages is depending 7th International Conference on Crack Paths The crack path prediction and fatigue durability estimation based on the damage function approach Ilia Nikitin a , Alexander Nikitin a, * a Institute for Computer Aided Desing RAS, 19/18, 2 nd Brestskaya st., Moscow, 123056, Russia Abstract In the process of the material degradation under cyclic loading is usually distinguishing several stages such as crack initiation, crack growth and final fracture. The local stress stage is cha ing with the degradatio proc ss and pecially during the crack g owth stage. The convenient approach to p dict th total fatigue life is usually b sed on two different problems: (1) use of a multiaxial criterion t estimate duration of th crack initiation; (2) used of Paris law to estimate the stable c ack growth d ration. However, during the evaluation of s ress state a differen crack opening modes can act. This chang i clearly obse ved in the case of pure torsion loading. The propagated torsion crack combines normal and shear cr k opening stage . The convenient approa hes are not suitable to predict such f tigue behavior of structural elements. This p pe is introducing a new approach to estimate the total fatigue life, inclu ing the crack initiation and propagation stages, with regards to c ack opening mechanisms. The proposed appro ch is based on the modern model of the full SN curve, d mage theory and takes int a account the normal and shear mech nisms of fatigue da ag accumulation. The paper contains th result of numerical simul ti n for VHCF torsion tests pr diction. © 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 CP 2021 – Guest Editors Keywords: VHCF; torsion; numerical simulation; damage theory; crack path; fatigue life prediction; crack opening. 1. Introduction In the process of the material fatigue failure is usually distinguished three different stages: (1) crack initiation; (2) crack pro agation; (3) fin l failure. Th inal fa lure is usually appearing in the last semi-cycle of loading and do not ontribute much to the tot tigu life. The contribution of crack initiation and crack propagation stages is depending 7th International Conference on Crack Paths The crack path prediction and fatigue durability estimation based on the damage function approach Ilia Nikitin a , Alexander Nikitin a, * a Institute for Computer Aided Desing RAS, 19/18, 2 nd Brestskaya st., Moscow, 123056, Russia

* Corresponding author. E-mail address: nikitin_alex@bk.ru * Corresponding author. E-mail address: nikitin_alex@bk.ru

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 CP 2021 – Guest Editors 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 CP 2021 – Guest Editors

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 CP 2021 – Guest Editors 10.1016/j.prostr.2022.03.133