PSI - Issue 13

Mirko Maksimović et al. / Procedia Structural Integrity 13 (2018) 1888 – 1894 Author name / StructuralIntegrity Procedia 00 (2018) 000–000

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4. Conclusions During service of several structures such as aircrafts structures, crack directions are not often normal to the loading direction. In such practical cases the direction of crack growth is not obvious. Tests to predict the fatigue crack growth trajectory for mixed-mode cracks are not only costly, but they do not also explain how each structural component in a complex structure could be optimized with another so that fatigue life of the overall structure can be predicted within reasonable limits for establishing the periods of inspection. For determination crack growth trajectories the conventional Paris`s and SED fatigue crack growth rate equations are used. In this work, a computation procedure to predict the direction and the growth rate of a mixed mode fatigue crack, using mode-I and mode-II data from finite elements, has been attempted. Computation of the crack growth trajectory is compared with experimental results. Good agreement between computation and experimental trajectories is obtained. The residual fatigue life along mixed mode crack growth trajectory is determined analytic and experimental. Good agreement between residual life estimation with experiment is obtained too. Acknowledgments The authors would like to thank the Ministry of Education and Science of Serbia for financial support under the project numbers OI 174001 and TR 35045. References Boljanović S, Maksimović S, Analysis of the crack growth propagation process under mixed-mode loading, Engineering Fracture Mechanics , Volume 78 , Issue 8, May 2011, pp 1565-1576. Erdogan F, Sih GC. On the crack extension in plates under plane loading and transverse shear. Trans. ASME. J Basic Engng 1963;85:519–25. Gdoutos EE. Problems of mixed mode crack propagation. The Netherlands: Martinus Nijhoff, 1984. Journet B, Ohrloff N, Pavlou D, Pantelakis S, Scra L, Poole D, Smart J. Investigation on Al-Li alloys for damage tolerant applications. B/E-3250 project, task 4 (Flight Simulation), Final Report DCR/M-60365/F-93, AEROSPATIALE, Suresnes, France, 1993. Khan SMA, Khraisheh MK. Analysis of mixed mode crack initiation angles under various loading conditions. Engng Fract Mech 2000;67:397– 419. Maksimović S., Vasović I., Maksimović M., Đurić M. RESIDUAL LIFE ESTIMATION OF DAMAGED STRUCTURAL COMPONENTS USING LOW-CYCLE FATIGUE PROPERTIES; Third Serbian (28th Yu) Congress on Theoretical and Applied MechanicsVlasina lake, Serbia, 5-8 July 2011; Serbian Society of Mechanics, Belgrade; ISBN: 978-86-909973-3-6; COBISS:SR-ID 187662860; 2011; pp 605 – 617 Marija Blažić, Katarina Maksimović, Yasmina Assoul, DETERMINATION OF STRESS INTENSITY FACTORS OF STRUCTURAL ELEMENTS BY SURFACE CRACKS, Third Serbian Congress Theoretical and Applied Mechanics, Vlasina Lake, 5-8 July 2011, pp. 374-383, Organized: Serbian Society of Mechanics, ISBN 978-86-909973-3-6, COBISS:SR-ID 187662860, 531/534(082). Maksimovic S., Maksimovic K., Improved Computation Method in Residual Life Estimation of Structural Components, Theoretical and Applied Mechanics, Special Issue – Adress to Mechanics , Vol. 40 (S1), 2012, pp. 223-246, doi: 10.2298/TAM12S1247M. (ISSN 1450-5584). Msc/NASTRAN software code- Theoretical Manuals Pantelakis S, Kermanidis T, Pavlou D. Fatigue crack growth retardation assessment of 2024-T3 and 6061-T6 aluminum specimens. J Theor Appl Fract Mech 1995; 22:35–42. Pavlou DG. Prediction of fatigue crack growth under real stress histories. Engng Struct 2000;22:1707–13. Paris PC, Erdogan F. A critical analysis of crack propagation. Trans. ASME. J Basic Engng 1963;85:528–34. Sih GC, Barthelemy BM. Mixed-mode fatigue crack growth predictions. Engng Fract Mech 1980;13(3):439–51. Stamenkovic, D., Maksimović, K., Nikolić-Stanojević, V., Maksimovic. S., Stupar, S., Vasović, I., “Fatigue Life Estimation of Notched Structural Components” Strojniški vestnik - Journal of Mechanical Engineering 56(2010)12, 860-866. Shafique MA Khan, Khraisheh Marwan K. Analysis of mixed mode crack initiation angles under various loading conditions. Eng Fracture Mech 2000;67:397–419.

Theoharis PS, Andrianopoulos NP. The T-criterion applied to ductile fracture. Int J Fracture 1982;20:R125 30. Qian J, Fatemy A. Mixed mode fatigue crack growth: a literature survey. Engng Fract Mech 1996;55(6):969–90.