Issue 50

N. Boychenko et alii, Frattura ed Integrità Strutturale, 50 (2019) 54-67; DOI: 10.3221/IGF-ESIS.50.07 66 Figure 13 : Creep SIF K cr distribution along the crack front in the temperature range taking into account damage accumulation. (1 – initial, 2 - intermediate, 3 - final crack fronts). C ONCLUSIONS n this study, a numerical analysis of an aircraft GTE compressor disc was conducted under operation loading conditions taking into account damage accumulation. Different combinations of disc rotation angular velocity, operating temperature, quarter elliptical crack form and size and elastic–plastic properties of the titanium alloy VT3-1 were compared. The constraint parameters in the form of the T z -factor, local stress triaxiality h and I n and cr n I -factor were analysed for the specified combinations of crack sizes and temperature conditions. The cr n I -factor, used as the foundation of the creep stress intensity factor, is sensitive to damage accumulation. The distributions of the governing parameters for the crack tip were represented along the crack front in the form of elastic, plastic and creep SIFs. A study under creep conditions were carried out taking into account the damage of material, revealing that elastic SIF is not sensitive to temperature. The principal advantage of the plastic and creep stress intensity factors is its sensitivity to real material properties and temperature. Damage accounting provides an opportunity to perform an objective carrying capacity assessment. Nonlinear SIFs are found to be attractive as a self-dependent unified parameter for the characterisation of fracture resistance under room and elevated temperatures. Based on the obtained numerical results of the present study, an ongoing work of the author will include crack growth rate and lifetime prediction. R EFERENCES [1] Makhutov, N.A., Vorobyev, A.Z., Gadenin M.M. at al. (1983). Prochnost' konstrukcij pri malociklovom nagruzhenii, Moscow: Nauka, 272p. [2] Zharoprochnye splavy dlja gazovyh turbin, edited by Shalin R.E. (1981). Moscow: Metallurgija, 479 p. [3] Shlyannikov, V.N., Zakharov, A.P., Yarullin, R.R. (2016). Structural integrity assessment of turbine disk on a plastic stress intensity factor basis, International Journal of Fatigue, 92 (part 1), pp. 234-245. DOI: 10.1016/j.ijfatigue.2016.07.016. [4] Kumar, R., Ranjan, V., Kumar, B., Ghoshal, S.K. (2018). Finite element modelling and analysis of the burst margin of a gas turbine disc using an area weighted mean hoop stress method, Engineering Failure Analysis, 90, pp. 425-433. DOI: 10.1016/j.engfailanal.2017.12.014. [5] Shlyannikov, V.N., Iltchenko, B.V., Stepanov, N.V. (2001). Fracture analysis of turbine disks and computational– experimental background of the operational decisions, Engineering Failure Analysis, 8 (5), pp. 461-475. DOI: 10.1016/S1350-6307(00)00041-8. [6] Shlyannikov, V.N., Yarullin, R.R., Zakharov, A.P. (2015). Fatigue life of power steam turbine disk material after loading history, Transactions of Academenergo, 3, pp. 78-91. I