PSI - Issue 39

Ilia Nikitin et al. / Procedia Structural Integrity 39 (2022) 599–607 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Conclusions The paper introduces the model for fatigue life and crack path prediction based on modern advances in fatigue and damage theory. The implementation of damage function in the stress state analysis allows to simulate the progressive damage and crack growth under arbitrary loading conditions. The proposed approach can be based on different multiaxial criteria. The proposed multi-mode model of fatigue damage developing capable to predict the locations of crack initiations and the type of crack opening. The numerical algorithm allows to take into an account the change in stress state during the crack nucleation and growth. The model was applied to the predict the crack path in smooth specimen loaded under pure torsion conditions. The results of numerical simulations show good agreement with the experimental data. The initial stage of crack growth was predicted in the Mode II with correct plane of main crack developing. The numerical procedure was capable to reproduce the bifurcation in crack path from maximum shear to maximum normal stress. The corresponding change in crack opening mechanism is also correctly simulated. Acknowledgements This work was supported by State Contract of Institute for Computer Aided Design RAS. Authors are thankful to Boris Stratula for his contribution in numerical simulations. References [1] Bathias C Paris P C 2004 Gigacycle fatigue in mechanical practice Dekker New York 328. [2] Shanyavskiy A A 1999 Fatigue in-service cracks growth in rotor blades of aircraft engines 7th International Fatigue Congress 1989–1994. [3] Shiozawa D Nakai Y Murakami T Nosho H 2011 Observation of Fatigue Crack Propagation Behavior under Torsional Loading by Using Synchrotron Radiation Micro-CT Imaging Procedia Engineering 10 1479- 484. [4] Davila C G Rose C A Murri G B and Jackson W C Langley 2020 Evaluation of Fatigue Damage Accumulation Functions for Delamination Initiation and Propagation William M. Johnston Science and Technology Corporation, Hampton, Virginia 1 - 38. [5] Gates N Fatemi A 2016 Multiaxial variable amplitude fatigue life analysis including notch effects Int. J. of fatigue 91 337–51. [6] Carpinteri A Spagnoli A Vantadori S 2011 Multiaxial assessment using a simplified critical plane based criterion Int. J. of Fatigue 33 969–976. [7] Burago N G Nikitin I S Nikitin A D Stratula B A 2019 Algorithms for calculation damage processes Frattura ed Integrità Strutturale 49 212– 24. [4] Nikitin I S Burago N G Zhuravlev A B and Nikitin A D 2020 Multimode Model for Fatigue Damage Development Mechanics of Solids 55(8) 298-306. [8] Nikitin A Bathias C Palin-Luc T 2015 A new piezoelectric fatigue testing machine in pure torsion for ultrasonic fatigue tests: application to forged and extruded titanium alloys Fatigue and Fracture of Engineering Materials and Structures Vol 38 Iss 11 pp 1294 - 1304. [9] Nikitin A Palin-Luc T Shanyavskiy A Crack initiation in VHCF regime on forged titanium alloy under tensile and torsion loading modes International Journal of Fatigue Vol 93 pp 318-325 [10] Nikitin A Palin-Luc T Shanyavskiy A Bathias C 2016 Comparison of crack paths in a forged and extruded aeronautical titanium alloy in torsion in gigacycle fatigue regime Engineering Fracture Mechanics Vol 167 pp 1125-1132