PSI - Issue 28

Y. Matvienko et al. / Procedia Structural Integrity 28 (2020) 584–590 Author name / Structural Integrity Procedia 00 (2019) 000–000

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implemented in Formula (6) without doubts. Figure 4b graphically illustrates damage accumulation for two different stress ranges.

6. Conclusion A new experimental approach for quantitative description of low-cycle fatigue damage accumulation is developed and implemented. The proposed destructive method employs preliminary low-cycle fatigue loading of specimens with holes and further inserting a sequence of narrow notches under constant external load. To quantify the effect of the stress ratio and stress range on damage accumulation in the vicinity of holes, the fracture mechanics parameters has been used. A measurement of deformation response caused by local material removing in the form of a notch is carried out by electronic speckle-pattern interferometry and transferred to fracture mechanics parameters. In this case, these notches serve to estimate a fatigue damage accumulation level similar to a probe hole for residual stress energy release in the hole-drilling method. Equality of square of areas lying under dependence of normalized SIF distributions versus lifetime, which are constructed for different parameters of cycles, provides the damage accumulation function in an explicit form. These functions are obtained for different stress ratios as well as stress ranges. Acknowledgements The authors acknowledge the support of the Russian Science Foundation (project N 18-19-00351). Coffin, L., 1954. Study of the effects of cyclic thermal stresses on ductile metals. Trans. ASME 76, 931-950. Collins, J., 1993. Failure of Materials in Mechanical Design: Analysis, Prediction, Prevention, 2 nd edition. NY, Chichester, Brisbane, Toronto, Singapure: John Wiley & Sons, pp. 672. Lalanne, C., 2014. Fatigue Damage. John Wiley & Sons, Ltd, London, Hoboken, pp. 535. Manson, S., 1953. Behavior of materials under conditions of thermal stress. HEAT transfer, Symp. Univ. Mech., Eng. Res. Inst., p. 9-75. Matvienko, Yu., Pisarev, V., Eleonsky, S., 2019. The effect of low-cycle fatigue on evolution of fracture mechanics parameters in residual stress field caused by cold hole expansion, Frattura ed Integrita Strutturale 47, 303-320. Pisarev, V., Matvienko, Yu., Eleonsky, S., Odintsev, I., 2017. Combining the crack compliance method and speckle interferometry data for determination of stress intensity factors and T-stresses, Engineering Fracture Mechanics 179, 348–374. Zerbst, U., Klinger, C., Clegg, R., 2015. Fracture mechanics as a tool in failure analysis – prospects and limitations, Engineering Failure Analysis, 55, 376-410. References